Download Nickel Copper Chromite Cobalt Deposits Werner Rex Bug Lakes

Ontario Geological Survey
Open File Report 5975
Geology of
Nickel-Copper-Chromite
Deposits and Cobalt-Copper
Deposits at Werner–Rex–Bug
Lakes, English River
Subprovince, Northwestern
Ontario
1998
ONTARIO GEOLOGICAL SURVEY
Open File Report 5975
Geology of nickel-copper-chromite deposits and cobalt-copper deposits at
Werner–Rex–Bug Lakes, English River Subprovince, Northwestern Ontario
by
J.R. Parker
1998
Parts of this publication may be quoted if credit is given. It is recommended that
reference to this publication be made in the following form:
Parker, J.R. 1998. Geology of nickel-copper-chromite deposits and cobalt-copper
deposits at Werner–Rex–Bug Lakes, English River Subprovince, Northwestern
Ontario; Ontario Geological Survey, Open File Report 5975, 178p.
e Queen’s Printer for Ontario, 1998
e Queen’s Printer for Ontario, 1998.
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Cette publication est disponible en anglais seulement.
Parts of this report may be quoted if credit is given. It is recommended that reference be made in the following form:
Parker, J.R. 1998. Geology of nickel-copper-chromite deposits and cobalt-copper deposits at
Werner–Rex–Bug Lakes, English River Subprovince, Northwestern Ontario; Ontario Geological Survey,
Open File Report 5975, 178p.
iii
Contents
Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
xi
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Location and Access . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Mineral Exploration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Previous Geological Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1
1
1
3
3
Regional Geological Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4
General Geology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Metasedimentary Migmatite . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Mafic Gneiss . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Intermediate to Felsic Intrusive Rocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tonalite-Trondhjemite-Granodiorite Suite . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Massive Granodiorite-Granite Suite . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Peraluminous Granitoid Suite . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Ultramafic to Mafic Igneous Rocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Ultramafic Rocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Mafic Rocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Relationship between Ultramafic and Mafic Rocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Structural Geology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Foliations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Lineations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Folds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Faults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Metamorphism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Amphibolite Facies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Granulite Facies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Alteration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Mineralization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Magmatic Mineral Deposits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Nickel-Copper Sulphide Mineralization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Disseminated Sulphide Mineralization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Remobilized Sulphide Mineralization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Chromite Mineralization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Remobilized Sulphide Mineralization in Migmatite, Pegmatite and Gneiss . . . . . . . . . . . . . . . . . . . . . . . . .
Cobalt-Copper Skarnoid Deposits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Werner Lake Cobalt-Copper Zone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Skarnoid Rocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Mineralization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Loon’s Nest Lake Zone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Skarnoid Rocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Mineralization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Classification of the Skarnoid Deposits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5
5
5
7
7
8
8
9
9
12
14
15
15
15
15
16
17
17
17
20
22
22
22
22
23
24
25
25
26
26
28
29
30
30
30
Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Genesis of the Werner–Rex–Bug Lakes Stratiform Intrusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Relationship with the Bird River Sill . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Genesis of Cobalt-Copper Skarnoid Deposits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
32
32
33
34
Recommendations for Mineral Exploration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
37
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Appendix 1: Descriptions of Mineral Deposits and Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
39
91
Metric Conversion Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178
v
FIGURES
1.
Location of the Werner-- Rex-- Bug lakes study area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
44
2.
Location of mineral deposits in the Werner-- Rex-- Bug lakes study area . . . . . . . . . . . . . . . . . . . . . . . . . . .
45
3.
Simplified regional geology of the Werner-- Rex-- Bug lakes study area . . . . . . . . . . . . . . . . . . . . . . . . . . .
46
4.
Chondrite-normalised REE patterns for mafic gneiss from Rex and Bug lakes . . . . . . . . . . . . . . . . . . . . .
47
5.
SiO2-TiO2 igneous/sedimentary discrimination diagram for mafic gneiss from Rex and Bug lakes and
typical metasedimentary rocks from the English River Subprovince . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
48
6.
Chondrite-normalised REE patterns for ultramafic rocks at Almo, Werner and Rex lakes . . . . . . . . . . . .
49
7.
A spider-diagram for primitive mantle-normalised REE and trace element patterns for the Upper and
Lower ultramafic suites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
50
8.
Chondrite-normalised REE patterns for gabbroic rocks from Almo, Werner and Rex lakes . . . . . . . . . . .
51
9.
A spider-diagram for primitive mantle-normalised REE and trace element patterns for gabbros from
Almo, Werner and Rex lakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
52
10.
Chondrite-normalised REE patterns for leucogabbro and anorthositic rocks at Rex and Bug lakes . . . . .
53
11.
A spider-diagram for primitive mantle-normalised REE and trace elements for leucogabbro or
anorthositic gabbro from Rex and Bug lakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
54
12.
Ternary diagrams of Fe2O3-MgO-Al2O3 and CaO-MgO-Al2O3 for ultramafic rocks, gabbros and
leucogabbros at Almo, Werner and Rex lakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
55
13.
MgO variation diagrams showing general enrichments and continuous compositional variations of
selected major element oxides from ultramafic rocks, gabbros and leucogabbros at Almo,
Werner and Rex lakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
56
MgO variation diagrams showing general enrichments and continuous compositional variations of
selected incompatible trace and rare earth elements from ultramafic rocks, gabbros and
leucogabbros at Almo, Werner and Rex lakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
57
MgO variation diagrams showing general depletion and continuous compositional variations of
selected compatible trace elements from ultramafic rocks, gabbros and leucogabbros at
Almo, Werner and Rex lakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
58
16.
Distribution of granulite grade rocks in the Werner-- Rex-- Bug lakes study area . . . . . . . . . . . . . . . . . . . .
59
17.
Chondrite-normalised REE patterns for orthopyroxene-cordierite-biotite-plagioclase rocks at
Rex and Bug lakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
60
18.
AFM plot after Reinhardt (1987) of orthopyroxene, cordierite and garnet-bearing rocks from
Rex and Bug lakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
61
19.
A plot of Cu/Au versus Cu/Ag for data from skarnoid deposits at Werner Lake and Loon’s
Nest Lake . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
62
20.
Cu-Au and Cu-Ag plots for data from skarnoid deposits at Werner Lake and Loon’s Nest Lake . . . . . . .
63
21.
Ag-Au and Co-Au plots for data from skarnoid deposits at Werner Lake and Loon’s Nest Lake . . . . . . .
64
22.
Location and general geology of the Bird River area in Manitoba . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
65
14.
15.
TABLES
1.
Major oxide geochemistry and Zr and Y values for mafic gneiss, metasedimentary
migmatite and mafic intrusive rocks at Bug Lake . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
66
2.
Rare earth element geochemistry for mafic gneiss, metasedimentary migmatite and
mafic intrusive rocks at Bug Lake . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
67
3.
Trace element geochemistry for mafic gneiss, metasedimentary migmatite and
ultramafic-mafic intrusive rocks at Bug Lake . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
68
4.
Major oxide geochemistry for gabbros and mafic gneiss at Almo-- Gordon-- Werner-- Rex lakes . . . . . . . .
69
5.
Rare earth element geochemistry for gabbros and mafic gneiss at
Almo-- Gordon-- Werner-- Rex lakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
70
vii
6.
Trace element geochemistry for gabbros and mafic gneiss at Almo-- Gordon-- Werner-- Rex lakes . . . . . . .
71
7.
Trace element geochemistry for gabbros and mafic gneiss at
Almo-- Gordon-- Werner-- Rex lakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
72
8.
Major oxide geochemistry for metasedimentary migmatites and granitoid rocks at
Almo-- Gordon-- Werner-- Rex lakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
73
9.
Rare earth element geochemistry for metasedimentary migmatite and granitoid rocks at
Almo-- Gordon-- Werner-- Rex lakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
74
10.
Trace element geochemistry for metasedimentary migmatite and granitoid rocks at
Almo-- Gordon-- Werner-- Rex lakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
75
11.
Trace element geochemistry for metasedimentary migmatite and granitoid rocks at
Almo-- Gordon-- Werner-- Rex lakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
76
12.
Major oxide geochemistry for the lower and upper ultramafic intrusive suites at
Almo-- Gordon-- Werner-- Rex lakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
77
13.
Rare earth element geochemistry for the lower and upper ultramafic intrusive suites at
Almo-- Gordon-- Werner-- Rex lakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
78
14.
Trace element geochemistry for the lower and upper ultramafic intrusive suites at
Almo-- Gordon-- Werner-- Rex lakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
79
15.
Trace element geochemistry for the lower and upper ultramafic intrusive suites at
Almo-- Gordon-- Werner-- Rex lakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
80
16.
Major oxide geochemistry for strongly altered ultramafic intrusive rocks and
orthopyroxene-cordierite rocks at Almo-- Gordon-- Werner-- Rex lakes . . . . . . . . . . . . . . . . . . . . . . . . . . . .
81
17.
Rare earth element geochemistry for strongly altered ultramafic intrusive rocks
and orthopyroxene-cordierite rocks at Almo-- Gordon-- Werner-- Rex lakes . . . . . . . . . . . . . . . . . . . . . . . . .
82
18.
Trace element geochemistry for strongly altered ultramafic intrusive rocks and
orthopyroxene-cordierite rocks at Almo-- Gordon-- Werner-- Rex lakes . . . . . . . . . . . . . . . . . . . . . . . . . . . .
83
19.
Trace element geochemistry for strongly altered ultramafic intrusive rocks and
orthopyroxene-cordierite rocks Almo-- Gordon-- Werner-- Rex lakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
84
20.
Major oxide and rare earth element geochemistry for skarnoid rocks at Werner
and Loon’s Nest lakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
85
21.
Trace element geochemistry for skarnoid rocks at Werner and Loon’s Nest lakes . . . . . . . . . . . . . . . . . .
86
22.
Trace element geochemistry for skarnoid rocks at Werner and Loon’s Nest lakes . . . . . . . . . . . . . . . . . .
87
23.
Geological characteristics of the Werner Lake cobalt mine and Loon’s Nest Lake occurrence . . . . . . . .
88
24.
Stages in the evolution of skarnoid deposits at the Werner Lake cobalt mine and
Loon’s Nest Lake occurrence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
88
25.
UTM co-ordinates (Grid Zone 15; NAD 27) for all samples collected and analyzed
from the Werner-- Rex-- Bug lakes study area. Northings and eastings obtained from
digitized 1:50 000 EMR topographic maps (52L/6 and 52L/7) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
89
GEOLOGICAL MAPS
Map P.3313 — Revised – Almo Lake Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
back pocket
Map P.3314 — Revised – Gordon Lake Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
back pocket
Map P.3315 — Revised – Werner Lake Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
back pocket
Map P.3316 — Revised – Upper Fortune Lake Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
back pocket
Map P.3317 — Revised – Rex Lake Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
back pocket
Map P.3380 — Revised – Bug Lake Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
back pocket
ix
Abstract
The Werner--Rex--Bug lakes area is located about 80 km north-northwest of Kenora near the Manitoba--Ontario provincial boundary and is situated within the Neoarchean English River metasedimentary
subprovince. The study area extends for approximately 32 km from Almo, Gordon and Werner lakes
in the west to Rex and Bug lakes in the east. Past mineral exploration and mining in the area has focussed on copper, cobalt and magmatic nickel-copper-platinum group element sulphide mineralization
hosted by ultramafic rocks and mafic gneiss. A cobalt mining operation was established at Werner
Lake by Canmine Resources Corporation in 1996.
The study area is underlain by a metasedimentary migmatite assemblage composed of quartz-feldspar-biotite gneiss derived from metasedimentary rocks and intruded by a succession of syn- to latetectonic felsic intrusive rocks including: tonalite-trondhjemite-granodiorite batholiths and plutons
(Marijane batholith, Gone Lake pluton); peraluminous granitoid rocks; granodiorite-granite sills; and
late-tectonic pegmatite dikes. The migmatite assemblage also hosts a small proportion of economically important syn-tectonic, deformed and altered, ultramafic and mafic igneous rocks and associated
mafic gneiss. The majority of rocks in the area have been affected by amphibolite to granulite grade
metamorphism.
The generally east-striking Werner--Rex lakes fault extends along the contact between the metasedimentary migmatite assemblage to the north and tonalite-trondhjemite-granodiorite batholiths to the
south. The fault is transected by crossfaults and breaks up into several fault splays that cut the migmatite assemblage and tonalitic rocks. The area is dominated by an east-striking fabric related to a
regional D2 deformation event and tight D2 folding that occurs locally in the metasedimentary migmatite assemblage.
The mineralogy, textures and geochemistry of ultramafic-mafic intrusive rocks at Werner--Rex-Bug lakes are characteristic of plutonic intrusions that have been modified by alteration, metasomatism and metamorphism. The ultramafic to mafic rocks consist of small, isolated bodies or lenses of
olivine-orthopyroxene-chromite cumulates and associated discontinuous bodies of gabbro, porphyritic
gabbro and anorthositic gabbro. The close spatial association between these rocks infers that they
evolved from the same magma source. This inference is supported by chemical trends and variations
that are consistent with fractional crystallization. The early evolution of the magma was controlled by
fractional crystallization of olivine, orthopyroxene, and chromite that produced ultramafic chromite
cumulates and caused the magma to become depleted in MgO and enriched in SiO2. Plagioclase was
subsequently fractionated out of the magma to form gabbro and anorthosite. These ultramafic-mafic
rocks may have been part of a single, syn-tectonic, ultramafic-mafic stratiform intrusion. The intrusion
was tectonically disrupted and boudinaged into small lenses and pods that were aligned along regional
faults and distributed throughout the metasedimentary migmatite. The ultramafic-mafic rocks at
Werner--Rex--Bug lakes are similar to the ultramafic-mafic rocks in the stratiform Bird River sill in
Manitoba.
Disseminated to semimassive magmatic nickel-copper-platinum group element sulphide and chromite mineralization is confined to ultramafic-mafic lenses and pods. A portion of the sulphide mineralization has been remobilized and disseminated into gneissic country rocks and felsic intrusive rocks
during deformation, metasomatism and anatexis.
High grade cobalt-copper deposits are hosted by magnesian iron replacement skarnoids in narrow,
east-striking deformation zones at intrusive contacts with porphyritic granite-granodiorite intrusions.
The term skarnoid refers to “skarn-like rocks of uncertain or complex origin” (Einaudi and Burt 1982)
and is a descriptive term for fine-grained, iron-poor, calcsilicate rocks which reflect the compositional
control of the protolith (Meinert 1992). Meinert (1992) states that, “skarnoid is intermediate between
a purely metamorphic hornfels and a purely metasomatic, coarse-grained skarn.” The mineralogy of
skarnoid rocks is not dominated by garnet or pyroxene and, therefore, does not have the typical mineralogy that defines a rock as a skarn (Meinert 1992). The skarnoids identified in the study area are interpreted to have formed by an invading metasomatic, hydrothermal fluid that replaced a serpentinized
and deformed ultramafic protolith. The magnesium enrichment of the skarnoid is directly related to
the high magnesium content of the original ultramafic rock. Cobalt-copper sulphide mineralization
xi
may have been derived from a combination of sources including serpentinized ultramafic rocks and
surrounding metasedimentary rocks.
There is a possibility for the discovery of other ultramafic-mafic intrusions within the migmatite
assemblage. Ultramafic-mafic bodies have been discovered in the metasediments up to 10 km north of
the Werner--Rex lakes fault and have been recognized along other regional faults. Regional surficial
sediment sampling conducted by Morris (1996) has identified abundant concentrations of spinel and
associated Ni, Cu, Zn, Pb and Co anomalies in humus and B and C horizon tills elsewhere in the
western English River Subprovince that may indicate the presence of other buried mineral deposits.
The fact that ultramafic-mafic bodies are widely scattered throughout the metasedimentary migmatite assemblage and distributed along several regional fault systems enhances the possibility of discovering more potentially economic nickel-copper and cobalt sulphide deposits in the English River
Subprovince. Surficial sediment sampling combined with ground and airborne geophysical surveys,
prospecting and detailed geological mapping may be effective in locating other ultramafic-mafic intrusive rocks.
xiii
Geology of
Nickel-Copper-Chromite Deposits and
Cobalt-Copper Deposits at
Werner–Rex–Bug Lakes,
English River Subprovince,
Northwestern Ontario
By J.R. Parker1
1Geologist, Precambrian Geoscience Section, Ontario Geological Survey, Sudbury
Ministry of Northern Development and Mines.
Manuscript approved for publication by A.J. Fyon, Senior Manager, Precambrian Geoscience Section, Ontario
Geological Survey, March, 1998.
Introduction
This Open File Report is a summary of results from 1:4800 scale detailed bedrock mapping in the
Werner--Rex--Bug lakes area of the Neoarchean English River Subprovince (Parker 1993, 1994,
1995a-e). The purpose of the mapping was to gain a better understanding of the structural and lithological controls on base and precious metal mineralization within the English River metasedimentary
subprovince and to document alteration associated with the mineralization. This project was conducted in conjunction with a 1:50 000 scale regional bedrock mapping project (Beakhouse 1993,
1994, 1997).
This report provides a summary of the major characteristics of the local and regional geology and
the mineral deposit types. Geochemical data from samples collected during this project are tabulated
in Tables 1 to 22, inclusive. Locational data (UTM) for each sample are tabulated in Table 25. Descriptions of mineral deposits, located in the study area, are included in Appendix 1.
LOCATION AND ACCESS
The Werner--Rex--Bug lakes area is situated about 80 km north-northwest of Kenora, adjacent to the
Manitoba--Ontario provincial boundary, in the English River Subprovince (Figure 1). The study area
extends for approximately 32 km from Almo, Gordon and Werner lakes in the west to Rex and Bug
lakes in the east (NTS 52 L\6NW, 7NW and 7NE).
The west part of the map area is accessible via Manitoba provincial highways 313 and 315 from
Lac du Bonnet, Manitoba and by the Gordon Lake mine road that crosses the Manitoba--Ontario provincial boundary north of Davidson Lake. Reynar, Almo, Gordon and Werner lakes are all accessible
from the mine road. The mine road extends for about 23 km from the Manitoba--Ontario border to the
north shore of Werner Lake, but is only accessible by truck to the south shore of Gordon Lake. The
remainder of the road must be accessed on foot or by ATV (all-terrain vehicle). Rex and Bug lakes are
accessible by floatplane.
An extensive area of forest, east of Werner Lake, was burned over in 1983 and subsequently
blown-down. As a result, access and travel at Rex Lake, Upper and Lower Fortune lakes and Bug
Lake is difficult and dangerous.
MINERAL EXPLORATION
The location of mineral occurrences, prospects and mines at Werner, Rex and Bug lakes are indicated
on Figure 2. Information on past mineral exploration work, included in this report, was taken from
assessment and mineral deposit files at the Kenora Resident Geologist’s office, unless otherwise indicated.
Mineral exploration at Werner--Rex--Bug lakes was initiated shortly after copper-nickel sulphide
mineralization was discovered at Maskwa, Manitoba in 1917 (Trueman 1971). The first recorded
mineral exploration work was conducted west of Werner Lake when M. Carlson discovered cobaltcopper mineralization in 1920. Kenora Prospectors and Miners Ltd. acquired the Carlson property in
1928 and developed test pits, trenches and a shallow shaft. The property became known as the Werner
Lake cobalt mine when seventy tons of cobalt ore, containing about 20 000 pounds of cobalt, was
mined and shipped to the Var--Lac--Oid Chemical Co. of Norwood, Ohio in 1932. In 1940 the property was leased to Norman B. Davis who operated the mine until it closed in 1944. The ore was handcobbed until 1942 when a small 25-ton/day mill was installed at the mine site. A 2-compartment shaft
was developed and deepened and a 42-foot adit was completed. A total of 123 386 pounds of cobalt
was shipped between 1940 and 1944. Total mine production was 143 386 pounds of cobalt with an
average grade of 2.2% Co and 0.75% Cu (Derry 1931; Chown 1955; Carlson 1958).
H. Byberg and A. Vanderbrink discovered nickel-copper mineralization in ultramafic rocks on the
southwest shore of Gordon (Lynx) Lake in 1942. Prospectors working for Dome Exploration Canada
Ltd. made similar discoveries at Werner and Loon’s Nest lakes also in 1942. Noranda Mines Ltd. optioned the Gordon Lake property and conducted extensive ground geophysical surveys and diamond
1
drilling during World War II. Rexora Mining Corporation Ltd. acquired the east part of the Gordon
Lake property in 1948 while the International Nickel Company of Canada Ltd acquired the west part.
Both companies conducted diamond drilling and geophysical surveys on their claims. Rexora had
outlined 2 mineralized zones with small tonnages, these were: the Rexora No.5 zone at Werner Lake
with 35 000 tons averaging 0.78% Ni and 0.42% Cu; and the Rexora No.2 zone on the southwest
shore of Gordon Lake with 140 000 tons averaging 1.53% Ni and 0.73% Cu (Taylor 1950; Carlson
1958). Falconbridge Nickel Mines Ltd. optioned the Rexora properties and conducted more diamond
drilling and ground geophysical surveys until 1949 (Taylor 1950; Carlson 1958; Scoates 1972).
In 1952 Quebec Nickel Corporation acquired all the ground formerly explored by Noranda, INCO,
Rexora and Falconbridge. Quebec Nickel conducted an extensive surface diamond drilling program
followed by the sinking of 2 shafts with considerable underground exploration and development. The
Quebec Nickel Corporation merged with the Eastern Smelting and Mining Corporation to form Eastern Mining and Smelting Corporation Ltd. in 1955, but the name was changed to the Nickel Mining
and Smelting Corporation Ltd. in 1958. The company was reorganized in 1963 to form Metal Mines
Ltd. and reorganized again in 1967 to form Consolidated Canadian Faraday Ltd. The Gordon Lake
Mine commenced production in 1962 and produced 1 370 285 tons averaging 0.92% Ni, 0.47% Cu,
0.004 ounce platinum per ton and 0.023 ounce palladium per ton until 1969 when underground operations were terminated and the shafts were closed. In 1971 it was reported that the mine had reserves
of 170 420 tonnes averaging 0.85% Ni and 0.35% Cu (Taylor 1950; Carlson 1958; Scoates 1972;
Mineral Deposit and Assessment Files, Resident Geologist’s office, Kenora).
In 1953 C. Alcock discovered nickel-copper mineralization in peridotite lenses at Almo (Tigar)
Lake. The properties were explored by Selco Exploration Co. Ltd. until 1954 when Norpax Oils and
Mines Ltd acquired them. Norpax developed a shaft and conducted extensive underground and surface exploration on the property. In 1962 the property was optioned to Nickel Mining and Smelting
Corporation Ltd. (Carlson 1958) and reserves of 1 010 000 tons averaging 1.2% Ni and 0.5% Cu were
reported (Canadian Mines Handbook 1963, p.215). Limited exploration work was conducted on this
property during the 1980’s.
Several companies conducted mineral exploration at Reynar, Rex and Upper and Lower Fortune
lakes, between 1942 and 1960, but no significant mineral discoveries were reported. Several mining
companies explored the Almo, Gordon, Werner and Rex lakes areas for platinum group elements during the mid-1980’s.
Prospectors working for Steep Rock Iron Mines Ltd. discovered copper sulphide mineralization at
Bug Lake between 1958 and 1961. During 1962 and 1963 Steep Rock Iron Mines Ltd. completed
geological mapping, trenching, stripping, sampling and magnetic, electromagnetic and self-potential
ground geophysical surveys at Bug Lake. In 1964 the Bug Lake property was acquired by Rio Tinto
Canadian Exploration Ltd. who conducted induced polarization ground geophysical surveys and diamond drilled 15 holes totalling 2955.5 feet. The diamond drilling tested several copper occurrences
located north of Bug Lake. Two diamond-drill holes totalling 555 feet were also diamond drilled on
the copper occurrences southeast of Bug Lake. Numerous mineralized sections were intersected in the
diamond drilling including: 0.61% Cu across 11.5 feet; 1.37% Cu across 17.7 feet; 2.09% Cu across
7.7 feet; and 1.44% Cu across 22.5 feet. Noranda Exploration Ltd. acquired the Bug Lake property
and conducted geological mapping, lithogeochemical surveys and magnetic and electromagnetic
ground geophysical surveys between 1985 and 1988. Samples taken from the trenches by Noranda
analysed up to 12% Cu from grab samples and 1.98% Cu across 17 feet from chip samples.
Since 1994, Canmine Resources Corporation has been conducting an intensive exploration program for copper, cobalt and gold at Werner, Rex and Bug lakes. The company has flown airborne
geophysical surveys over the entire area, conducted ground geophysical surveys and completed over
75 000 feet of diamond drilling. The company is presently focussing its attention on the cobalt mineralization at the West cobalt zone occurrence. Approximately 3100 tonnes of mineralized material was
shipped to Sudbury for metallurgical testing and the company announced plans to initiate underground
development in 1996. Diamond drilling outlined approximately 14 000 tonnes averaging 1.57% Co,
0.26% Cu and 0.113 ounce gold per ton at the West cobalt zone (Canada Stockwatch, February 23,
1996, p.11). The company commenced underground mining operations in late 1996 by developing a
ramp into the West zone and extracting about 10 000 tonnes of cobalt ore before the end of 1997. A
2
total of 847 feet of underground ramping, drifting and raising was completed. Underground chip sampling gave the following cobalt values: 3.0% Co, 15% Co, 15.7% Co, 18.5% Co and 20% Co (Canmine Resources Corporation, News Release, October 23, 1997).
PREVIOUS GEOLOGICAL STUDIES
D.R. Derry conducted a reconnaissance survey of a large area from Minaki to Sydney Lake and examined rocks in the vicinity of Reynar, Werner, Rex and Rowdy lakes in 1929 (Derry 1931). J.F.
Wright examined and described the geology at the Werner Lake cobalt mine for the Geological Survey
of Canada in 1931 (Wright 1932). E.O. Chisholm (1949) described the copper-nickel and cobalt occurrences at Almo, Gordon, Werner and Rex lakes and H.D. Carlson conducted 1: 31 680 scale bedrock mapping of the Werner--Rex lakes area during the summers of 1954 and 1955 (Carlson 1958).
E.R. Rose conducted a mineralogical and geochemical study of the Gordon Lake nickel deposit in
1956 for the Geological Survey of Canada (Rose 1958).
Thesis studies were conducted at the Werner Lake cobalt mine (Chown 1955), at the Rexora nickel-copper properties (Taylor 1950) and at the Gordon Lake Mine (Scoates 1963, 1972).
During 1987 C.E. Blackburn (Blackburn et al. 1988) and G.E. Lawson and P. Zuberec (1987) conducted reconnaissance surveys of the nickel-copper and cobalt occurrences in the Werner--Rex lakes
area.
G.P. Beakhouse conducted regional 1:50 000 scale bedrock mapping of the Werner--Rex lakes area
in 1992, 1993 and 1994 (Beakhouse 1993, 1994, 1997) and T. Morris completed Quaternary mapping
and sampling at Almo, Werner and Rex lakes (Morris 1996). A study of the copper mineralization at
Bug Lake was conducted in August 1993 (Parker 1993, Parker and Laporte 1993). The present study
was conducted during the summer of 1994.
ACKNOWLEDGEMENTS
The author thanks N. Laporte and C. McFarlane for able assistance in the field during the summers of
1993 and 1994, respectively. Thanks also to C.E. Blackburn and M. Guderyan, Kenora Resident
Geologist’s office, for logistical support and the use of their facilities and equipment; Bob Heinrichs at
Gordon Lake for logistical support and hospitality; W. Ferreira and T. Ellwood of Canmine Resources
Corporation for their support; and to G. P. Beakhouse for critically reviewing this report.
Unless otherwise noted, all data for geochemical analyses presented in this report were provided
by the Geoscience Laboratories, Ontario Geoservices Centre in Sudbury. Several minerals described
in this report were identified using X-ray diffraction (XRD) analysis conducted by S. Miller at the
Geoscience Laboratories.
3
Regional Geological Setting
The study area is underlain by a migmatite assemblage composed of quartz-feldspar-biotite gneiss derived
from metasedimentary rocks and intruded by a complex succession of syn-tectonic tonalite-trondhjemitegranodiorite batholiths and plutons; syn-tectonic peraluminous granitoid rocks; syn- to late-tectonic granodiorite-granite sills; and late-tectonic pegmatite dikes. The migmatite assemblage also hosts a small
proportion of economically important syn-tectonic, deformed and altered, ultramafic and mafic igneous
rocks and associated mafic gneiss (Beakhouse 1997; Figure 3).
Metamorphic grade within the metasedimentary migmatite assemblage ranges from amphibolite
grade at Almo, Gordon and Werner lakes in the west to granulite grade at Upper and Lower Fortune
lakes, Rex Lake and Bug Lake in the east. Metasedimentary and igneous rocks at Rex and Bug lakes
contain mineral assemblages that include abundant but variable amounts of coarse-grained garnet, cordierite and orthopyroxene.
The generally east-striking Werner--Rex lakes fault extends along the contact between the metasedimentary migmatite assemblage to the north and tonalite-trondhjemite-granodiorite batholiths to the
south at Almo, Gordon and Werner lakes (see Figure 3). The fault is transected by crossfaults at Almo
and Werner lakes and breaks up into several fault splays that cut the migmatite assemblage and tonalitic rocks at Werner and Rex lakes (Carlson 1958; Parker 1995a-e). The area is dominated by an eaststriking fabric related to a regional D2 deformation event (Breaks 1991) and tight D2 folding that occurs locally in the metasedimentary migmatite assemblage.
Inclusions of gabbro, anorthosite and ultramafic rocks as well as deformed mafic dikes occur in
the highly strained tonalitic rocks south of the Werner--Rex lakes fault. Numerous mafic and ultramafic tectonic inclusions or boudins are also distributed throughout the metasedimentary migmatite assemblage. Isolated ultramafic pods occur within or adjacent to the Werner--Rex lakes fault and host
nickel-copper sulphide mineralization, chromite and platinum group elements. Strongly metasomatized and altered ultramafic rocks host cobalt-copper sulphide mineralization at Werner Lake.
4
General Geology
METASEDIMENTARY MIGMATITE
An east-striking assemblage of metasedimentary rocks and derived migmatite is located north of the
Werner--Rex lakes fault (see Figure 3). The assemblage consists of quartzofeldspathic gneisses interpreted as metamorphosed turbiditic wackes and pelitic rocks with very minor discontinuous units of
calcsilicate and magnetite-rich pelite layers. Numerous granitoid stocks and plutons interrupt the continuity of the metasedimentary assemblage.
The majority of the metasedimentary migmatite assemblage consists of equigranular, granoblastic,
and “sugary-textured” wacke composed of quartz + feldspar + biotite. The wackes are moderately to
strongly foliated and fine- to coarse-grained. The wacke is buff brown-grey or rusty orange-brown on
weathered surfaces with a low colour index ranging between 5 and 35. The wacke is weakly to
strongly porphyroblastic with garnet, cordierite and orthopyroxene in areas of moderate to high-grade
metamorphism.
Wacke is interlayered with minor pelitic rocks that are equigranular, granoblastic and strongly foliated; dark brown-grey on weathered surfaces; and biotite-rich with aluminous porphyroblastic minerals such as garnet and cordierite. The pelitic layers are coarse grained and porphyroblastic in areas of
moderate- to high-grade metamorphism and may host abundant garnet with accessory biotite and cordierite. Thin (< 10 cm) garnetiferous layers with abundant biotite, dark green-black amphibole and
abundant disseminated magnetite represent thin units of iron-rich pelitic rocks.
Metamorphism and deformation have obliterated most primary sedimentary structures. Bedding
cannot be determined with certainty and it’s not obvious whether the banding-layering observed in
outcrop is a metamorphic feature or sedimentary in origin. The metasedimentary migmatite commonly consists of interlayered garnet-rich and garnet-poor mineral assemblages. The size of garnet porphyroblasts also varies from layer to layer. This variation is interpreted to be indicative of primary
sedimentary bedding where garnet-rich assemblages are derived from iron-rich metasediments interlayered with iron-poor feldspathic wackes represented by garnet-poor layers. Therefore, variation in
iron content and bulk composition between metasedimentary rocks reflects layering in areas of highgrade metamorphism.
Calcsilicate rocks were observed at Bug and Rex lakes and consist of small (< 0.5 m), greenwhite, elliptical nodules, lenses or layers of medium- to coarse-grained magnetite + plagioclase +
green diopside.
Metatexite is a common migmatite type in the study area and contains between 10 and 50% stromatic granitoid leucosome localized along foliation parallel layers (Breaks and Bond 1993). The
leucosome is produced by partial or differential melting of metasediments during anatexis and consists
of sodic and/or potassic feldspar + quartz + biotite and may be highly peraluminous with large, purple
cordierite crystals (up to 20 cm x 11 cm in size) and/or garnet crystals. Leucosome may contain orthopyroxene in areas of granulite metamorphism. Leucosome patches and veins commonly have biotite or garnet-biotite selvages that vary in width from 3 to 30 cm along the margins of the veins.
Geochemical data for samples collected from the metasedimentary migmatite are tabulated in
Tables 1, 2, 3, 8, 9, 10 and 11.
MAFIC GNEISS
Mafic gneiss is concordant with the metasedimentary migmatite assemblage but is always closely affiliated with ultramafic-mafic intrusive rocks. The gneiss forms a thin (< 150 m thick), discontinuous,
arcuate unit that extends for about 8 km along the Werner--Rex lakes fault from Rex Lake to Bug Lake
(see Figure 3). The mafic gneiss is interlayered with gabbroic and anorthositic rocks at Rex and Fortune lakes and is adjacent to anorthositic rocks at Bug Lake. The gneiss is also widespread as a minor
component of the metasedimentary migmatite (Beakhouse 1993, 1997) and occurs as thin (< 20 cm to
15 m), discontinuous lenses and layers.
5
The mafic gneiss consists of medium- to coarse-grained, granoblastic to gneissic rocks composed
of variable amounts of plagioclase (30 to 60%) + magnetite (5 to 15 %) + amphibole (20 to 50%) +
biotite (20 to 50%) + quartz. The gneiss is rusty orange-brown to buff grey-brown on weathered surfaces with a colour index ranging from 20 to 50. The mafic gneiss exhibits layering at Bug and Rex
lakes where dark green-black amphibole-rich layers alternate with white-grey feldspar-rich layers; and
fine-grained layers alternate with medium- to coarse-grained layers. The layering commonly has
gradational contacts from one layer to the next. The small amount of quartz and abundance of mafic
minerals in the mafic gneiss are characteristic features that distinguish it from wacke and pelitic rocks.
The mafic gneiss is weakly to strongly porphyroblastic in areas of high-grade metamorphism and
commonly contains orthopyroxene, garnet and cordierite. In general, the gneiss hosts less garnet and
more abundant cordierite and orthopyroxene than the metasedimentary migmatite which is indicative
of elevated MgO content (Dallmeyer 1972; Schreurs and Westra 1985) in the mafic gneiss. Cordierite-rich and cordierite-poor mineral assemblages are interlayered within individual outcrops of mafic
gneiss inferring a variation in magnesium content that may be indicative of: 1) primary layering; or 2)
localized magnesium enrichment due to hydrothermal alteration. The gneiss may contain 50 to 90%
cordierite or garnet and hosts irregular and discontinuous patches of cordierite + orthopyroxene + plagioclase + garnet + biotite leucosome. The mafic gneiss commonly contains 0-10% leucosome, which
is typical of mafic rocks in areas of high-grade metamorphism (Breaks and Bond 1993).
The mafic gneiss at Bug Lake is characterized by 41.9 to 49.8% SiO2, 12.1 to 15.5% Al2O3, 3.4
to 13.2% MgO, 0.63 to 1.52% TiO2, 4-23 ppm Y and 81-173 ppm Zr with Zr/Y = 4.7-22.5 (see Table
1). The mafic gneiss at Rex Lake is characterized by 52.46 to 57.23% SiO2, 11.2 to 14.1% Al2O3,
5.47 to 9.61% MgO, 0.64 to 0.81% TiO2, 7-19 ppm Y and 81-105 ppm Zr with Zr/Y = 4.2-13 (Tables
4 and 7). The mafic gneiss at Rex Lake has an intermediate composition with less variation in Y, Zr
and TiO2 concentrations compared to mafic gneiss at Bug Lake. Chondrite-normalised REE (rare
earth elements) for mafic gneiss (Figure 4) are 30 to 100 times ordinary chondrites and define moderately steep patterns with enriched light REE and depleted heavy REE with strong troughs from Gd to
Tm. The REE patterns show that mafic gneiss at Rex Lake is generally more evolved than mafic
gneiss at Bug Lake. Most mafic gneiss samples show essentially the same type of REE patterns (see
Figure 4) with consistent differences in total REE abundance indicating a continuity in chemical
trends among the samples. REE and trace element data for mafic gneiss are presented in Tables 1, 2,
3, 4, 5, 6 and 7.
The REE patterns also display inconsistent Eu anomalies that vary from weak negative to moderately positive (see Figure 4) and indicate possible Eu2+ mobility during alteration and replacement of
primary mafic minerals (Sun and Nesbitt 1978). The enriched light REE and variable Eu anomalies
may be an affect of alteration, metasomatism and REE mobility during high grade metamorphism
(Pan and Fleet 1996) and metamorphic reactions with felsic intrusive rocks. Light REE enrichment
may also be due to crustal contamination. Many rocks contain REE-rich accessory minerals such as
zircon, monazite and apatite, which may explain the enrichment of light REE (Pan and Fleet 1996). A
sample of granulite grade mafic gneiss from Bug Lake contains anomalously high light REE such as
566.3 ppm La and 645 ppm Ce (see Table 2, sample 93JRP-120).
Bulk chemical features of mafic gneiss indicate that it is chemically distinct from typical wackes
and pelites in the English River Subprovince. Typical wackes have an excess of Na2O over K2O
while pelitic rocks always contain greater than 17% Al2O3 (Breaks and Bond 1993). In comparison,
mafic gneiss commonly has Al2O3 concentrations consistently less than 17% with an excess of K2O
over Na2O manifested by abundant biotite or low modal plagioclase and high modal amphibole (see
Tables 1 and 4). An igneous/sedimentary discrimination diagram (Tarney 1976) of TiO2-SiO2 (Figure
5) shows mafic gneiss samples plotted with average English River wackes and pelites from Zealand
Township (data provided by F.W. Breaks, Geoscientist, Ontario Geological Survey, 1997) and volcaniclastic metasedimentary rocks from Pakwash Lake (data from Van De Kamp and Beakhouse 1979).
The majority of mafic gneiss samples plot in the igneous field of the diagram (see Figure 5) indicating
that the gneiss is either an igneous rock or an immature metasedimentary rock derived from igneous
rocks.
The mafic gneiss has been interpreted as metamorphosed and altered mafic metasedimentary rock
and/or tuff and/or metamorphosed gabbroic rock (Beakhouse 1993, 1994). The author interprets the
6
mafic gneiss as a metamorphosed and altered intermediate to mafic intrusive rock for the following
reasons:
1)
2)
3)
4)
5)
The majority of mafic gneiss is almost always spatially associated with ultramafic-mafic
intrusive rocks.
The gneiss is commonly quartz-poor and enriched in mafic minerals.
The gneiss is chemically distinct from typical English River wackes and pelites.
Chondrite-normalised REE patterns for the mafic gneiss show consistent differences in
total REE abundance indicating continuity in chemical tendencies among the samples.
The gneiss is mineralogically and texturally similar to gabbroic rocks at Almo, Gordon
and Bug lakes.
INTERMEDIATE TO FELSIC INTRUSIVE ROCKS
Tonalite-Trondhjemite-Granodiorite Suite
The Marijane batholith and Gone Lake pluton are interpreted (Breaks 1991) to be part of a syn-tectonic igneous suite of tonalitic to granodioritic rocks that were emplaced within the metasedimentary
migmatite assemblage at about 2698 Ma (Breaks 1991; Corfu et al. 1995). The Marijane batholith is
also interpreted to be coeval with the Maskwa batholith in Manitoba (Trueman 1980).
The Marijane batholith is an extensive, linear mass that extends east from Manitoba to the west
end of Rex Lake (see Figure 3). The south margin of the batholith is adjacent to the English River-Winnipeg River Subprovince boundary. The Werner--Rex lakes fault extends along the north contact
of the batholith and cuts the contact in a few locations. The north margin of the batholith is comprised
of medium-grained, equigranular, leucocratic, tonalitic to granodioritic rocks consisting of plagioclase
+ quartz + potassic feldspar + amphibole + biotite with accessory apatite, zircon, chlorite, sericite and
magnetite. Rare, large (< 1.5 cm), magnetite + actinolite clots were observed at several locations.
The tonalite is locally porphyritic with abundant, 0.5 to 2 cm, euhedral to subhedral, plagioclase phenocrysts. The tonalitic rocks are buff-grey with patchy pink areas on weathered surfaces.
The batholith is very strongly foliated and variably mylonitized in proximity to the Werner--Rex
lakes fault and contains many “streaky” and patchy gneissic areas along the south shore of Almo
Lake. The batholith contains xenoliths of metasedimentary rock and amphibolite along its margins.
The batholith also contains several dark, ovoid, mafic to ultramafic xenoliths and remnants of gabbroic rocks “plastered” along faces of tonalitic outcrops on the south shore of Gordon Lake (footwall of
Werner--Rex lakes fault).
The Marijane batholith hosts a few irregular, patchy areas of abundant disseminated cordierite and
garnet porphyroblasts (< 2 cm in size) in foliated tonalitic rocks at Werner and Rex lakes. The occurrence of cordierite + garnet is unusual in tonalitic rocks and is due to pre-metamorphic hydrothermal
alteration of feldspar that was subsequently replaced by cordierite + garnet during metamorphism.
Similar patchy alteration occurs at Rex Lake but includes narrow garnet-cordierite veins and dark
patches of orthopyroxene + magnetite (Beakhouse 1994, 1997; G.P. Beakhouse, personal communication, 1994).
Geochemical data for 2 samples collected from the Marijane batholith are tabulated in Tables 8, 9,
10 and 11.
The Gone Lake pluton is a discrete, ovoid body of leucocratic, medium-grained, equigranular, granodioritic rocks consisting of quartz, plagioclase, potassic feldspar, biotite, amphibole and magnetite.
The north and east margins of the pluton are exposed along the south shore of Rex Lake and the west
shore of Bug Lake, respectively (see Figure 3). The pluton is enclosed within granulite grade metasedimentary migmatite (Breaks 1991). Foliation and banding within the migmatite has been deflected
around the external margins of the pluton. The Gone Lake pluton has been reported by Breaks (1991)
to contain orthopyroxene-bearing charnockitic rocks commonly restricted to granulite grade metamorphic zones (Condie and Allen 1984; Windley 1982; Kramers and Ridley 1989).
At Bug Lake, a north-northwest-striking fault extends along the east contact of the Gone Lake pluton where the pluton is moderately to strongly foliated. The pluton also contains diffuse pegmatitic
7
phases and foliation parallel pegmatitic veins. The marginal rocks of the pluton host xenoliths of mafic gneiss, anorthosite and garnet-cordierite-bearing metatexite at Bug Lake and xenoliths of anorthosite at Rex Lake.
Metamorphosed alteration assemblages were recognized in strongly foliated granodioritic rocks of
the Gone Lake pluton at Bug Lake. The alteration consists of thin (< 6 cm), foliation parallel layers of
garnet + biotite + magnetite + cordierite.
Massive Granodiorite-Granite Suite
Granodiorite-granite intrusions are considered to be part of a syn-tectonic igneous suite emplaced
between 2698 Ma and 2560 + 40 Ma (Breaks 1991; Corfu et al. 1995). Several large intrusions are
situated north of Almo and Werner lakes, at Upper Falls Lake and at the Werner Lake cobalt mine (see
Figure 3).
These rocks form linear, east-trending, sill-like bodies enclosed within the metasedimentary migmatite assemblage. The intrusions commonly consist of leucocratic, pink weathering, medium- to
coarse-grained, granodiorite to granite with equigranular phases and potassium feldspar megacrystic
(porphyritic) phases. The rocks have a simple mineralogy consisting of potassium feldspar, plagioclase, quartz and biotite with accessory epidote, magnetite, sericite and rare amphibole.
Granodiorite-granite intrusions are commonly massive to weakly foliated with the exception of
intrusions adjacent to the Werner--Rex lakes fault. Exposures of granodiorite-granite on the Gordon
Lake mine road, between the Werner Lake cobalt mine and the Werner--Rex lakes fault, are strongly
foliated and strongly epidotized along late fractures and joints. Gabbroic and metasedimentary xenoliths were observed in some intrusions.
The granite-granodiorite intrusions are spatially and possibly genetically related to the cobalt-copper deposits at Werner and Loon’s Nest lakes (see Cobalt-Copper Skarnoid Deposits in this report).
The East cobalt zone at the north end of Werner Lake is enclosed within a granodiorite-granite sill.
The intrusion is weakly altered in the vicinity of these deposits.
Peraluminous Granitoid Suite
The syn- to late-tectonic peraluminous granitoid suite consists of relatively small, tabular S-type
granitoid masses produced by regional anatexis (melting) of clastic metasedimentary rocks during low
pressure, high temperature metamorphism (Breaks 1991). Large areas of peraluminous granitoid
rocks are located north of Rex Lake, at Bug Lake and at Upper and Lower Fortune lakes.
In general, peraluminous granitoid rocks in the English River Subprovince have distinctive petrochemical features that include high normative corundum; high initial Sr ratios; general dominance of
Fe2+ over Fe3+; high O18 isotope values; absence of amphibole; and the presence of aluminous accessory minerals such as cordierite and garnet (Breaks and Bond 1993). The peraluminous granitoid
suite was emplaced within the English River Subprovince at approximately 2691 Ma during the development of a dominant east-striking regional fabric (Corfu et al. 1995; Breaks 1991). Peraluminous
granitoids are commonly massive to weakly foliated but may be strongly foliated and host narrow
(less than 1 m) faults and mylonite zones in the vicinity of the Werner--Rex lakes fault.
The peraluminous granitoids have been mapped as diatexites and were produced by high-grade
anatexis resulting in complete melting of the metasedimentary country rocks (Breaks and Bond 1993).
The diatexite in the study area has a massive, plutonic, granitoid appearance with distinctive chalky
white weathered surfaces and an average medium to coarse grain size (although grain size is extremely
variable) with numerous irregular patchy pegmatoid phases. The diatexites do not contain continuous
migmatitic banding or stromatic structures. The diatexite commonly consists of plagioclase, quartz,
biotite and magnetite with randomly disseminated, accessory aluminous minerals such as garnet and
cordierite. Garnet and cordierite are uncommon in most granitic rocks but are distinctive constituents
of the peraluminous granite suite (Breaks and Bond 1993). Garnet porphyroblasts (1 to 3 cm in size)
are strongly poikilitic and tend to be concentrated in slightly coarser grained phases of diatexite. Garnets are also distributed in small clusters of crystals giving the diatexite a “clotty” appearance. Garnet
clusters may also contain cordierite, biotite, plagioclase, quartz and sillimanite (G.P. Beakhouse, personal communication, 1997). Magnetite may be disseminated throughout the diatexite or occur as
large, irregular semi-massive clots in coarse-grained phases.
8
Homogeneous and inhomogeneous diatexites are transitional phases based on the abundance of
remnant material leftover from the melting of the original clastic metasedimentary rocks (Breaks and
Bond 1993). Inhomogeneous diatexite is the most abundant phase in the study area and has a chaotic
or turbulent appearance consisting of granitoid and pegmatoid material with variable quantities (10 to
40%) of remnant wacke and pelitic paleosome and mafic to ultramafic enclaves (Breaks and Bond
1993). The paleosome enclaves vary in size from large rafts to small blocks and are strongly foliated,
contorted and plastically deformed. The enclaves may have reaction rims; distinct boundaries; or may
be partially assimilated with diffuse boundaries. Homogeneous diatexite consists of massive granitoid
material with 0 to10% remnant paleosome enclaves (Breaks and Bond 1993). Contacts between metatexite and the 2 phases of diatexite are gradational, diffuse and irregular. The abundance of inhomogeneous diatexite and general lack of distinct contacts suggests that the masses of anatectic melt did not
move far from the original site of melting and amalgamation (Breaks and Bond 1993).
Geochemical data for 1 sample from the peraluminous granitoid rocks are tabulated in Tables 8, 9,
10 and 11.
ULTRAMAFIC TO MAFIC IGNEOUS ROCKS
Ultramafic Rocks
Isolated lenses, layers and podiform bodies of syn-tectonic ultramafic rocks are distributed along the
Werner--Rex lakes fault and its associated splays. Ultramafic pods also occur as discontinuous chains
or isolated bodies that are concordant with lithologic layering throughout the metasedimentary migmatite assemblage (see Figure 3).
The ultramafic pods have variable sizes ranging from less than 0.5 m to 180 m in length. The
pods at the Gordon Lake Mine are 180 m x 45 m x 180 m (Scoates 1972) and are the largest ultramafic bodies documented in the study area. Exposures of ultramafic rocks commonly appear as small,
rounded, protruding outcrops with dark green and rusty weathered surfaces. The rocks are fine- to
coarse-grained, dark grey or black on fresh surfaces and tend to be quite hard. Ultramafic pods and
lenses, situated along the Werner--Rex lakes fault at Gordon Lake, are elongated parallel to the strike
of the fault and are elliptical, north-dipping, northwest-plunging bodies that have greater vertical than
lateral extent (Scoates 1972). The interior of the ultramafic pods are relatively undeformed with a
weak preferred orientation of platy and acicular minerals. Platy biotite crystals, along the margins of
the pods, show strong preferred orientations parallel to sheared contacts. The ultramafic rocks are
commonly associated with gabbroic and anorthositic rocks and host magmatic nickel-copper-platinum
group element sulphide mineralization and chromite.
Scoates (1972) classified the majority of the ultramafic rocks at Gordon are classified as hornblende peridotites, peridotitic hornblendites and peridotites (Scoates 1972). Scoates (1972) examined
the weakly altered cores of large ultramafic pods at the Gordon Lake Mine and reported that the primary igneous mineralogy consists of olivine (Fo73.8 to Fo85.1 ; average Fo79.8) + orthopyroxene (En76
to En92 ; average En85.5) + hornblende + chrome spinel with minor clinopyroxene.
Original mineralogy and primary igneous textures in the majority of ultramafic pods have been
obscured and modified by replacement reactions and re-equilibration between mineral phases that developed during initial cooling and serpentinization; regional metamorphism; intrusion of felsic intrusive rocks; and retrograde serpentinization. The altered ultramafic rocks are essentially composed of
metamorphic amphibole; secondary magnetite and serpentine; biotite; serpentinized orthopyroxene;
and remnant chrome spinel. The rocks contain variable amounts of other secondary minerals such as:
chlorite, clinochlore, talc, phlogopite, hercynite (dark green iron spinel), hematite and calcite.
Secondary amphiboles replace primary pyroxene and previously serpentinized ultramafic rock.
The most common amphibole is dark green actinolite-tremolite that occurs as elongate, acicular crystals and radiating patches of crystals with grain sizes ranging from 1 mm to 10 cm. Samples of ultramafic rock from waste dumps at the Gordon Lake Mine contain actinolite crystals up to 30 cm in
length. Other amphiboles such as hornblende occur as stubby black crystals while anthophyllite occurs as long lath-like crystals with feathery terminations (Scoates 1972). All amphiboles are variably
altered to chlorite and serpentine. Orthopyroxene occurs as stubby or blocky, dark brown to black
9
crystals with ragged boundaries due to serpentinization. Coarse-grained, chloritic, biotite is concentrated along the margins of ultramafic pods or in alteration halos adjacent to granitic pegmatite dikes
and peraluminous pegmatoid veins that intrude the ultramafic rocks.
Alteration of the ultramafic rocks has been caused by the addition of water and other volatiles resulting in the replacement of mafic silicate minerals, such as olivine and pyroxene, by serpentine minerals. The ultramafic rocks experienced at least 2 separate serpentinization events consisting of 1) an
original serpentinization during initial cooling (Scoates 1972); and 2) a later, higher temperature serpentinization after peak regional metamorphism (Scoates 1972). Serpentine minerals from the original serpentinization, consisting of chrysotile and bastite (after pyroxene), were recognized by Scoates
(1972) in the weakly altered cores of large pods at the Gordon Lake Mine. In most cases, however,
the original serpentinization cannot be recognized due to subsequent metamorphism and metasomatism.
Antigorite is the predominant serpentine mineral in strongly altered recrystallized ultramafic rocks
(Scoates 1972). Antigorite has a high thermal stability (Cerny 1968; Winkler 1976; Coats and Buchan
1979) and may have formed under upper greenschist-lower amphibolite conditions (Coats and Buchan
1979; Whittaker 1986) during the second, higher temperature serpentinization that post-dated peak
regional metamorphism. The serpentine minerals are black-green or green-grey on fresh surfaces and
chalky white or pale green on weathered surfaces. The ultramafic rocks are extensively serpentinized,
however, the intensity of serpentinization is variable and ranges from incipient to total replacement
with large interlocking patches of antigorite. Antigorite veinlets and fracture-fillings (< 2 mm to 4
mm thick) are common and transect chromite layers and all mineral assemblages. Other minerals that
accompany antigorite are talc, bastite, biotite-phlogopite and chlorite.
Magnetite is common and abundant in the ultramafic rocks and occurs in thin stringers and veins;
irregular patches or clumps; and as disseminated angular grains that appear as black or dark grey
knobs on weathered surfaces. Hematite also occurs in ultramafic rocks intersected in diamond-drill
core at the Norpax prospect at Almo Lake (Assessment files 52L06NE K-2, T-1, R-1); at the Dome
No.3 occurrence at Werner Lake (Assessment file 52L07NW D-1); and the Radioactive Minerals occurrence at Rex Lake (Assessment file 52L07NE R-1; DDH FO-4). At Rex Lake, specular hematite is
disseminated or occurs as “patches” and “seams” in the ultramafic rocks (Assessment file 52L07NE
R-1; DDH FO-4).
Carbonate does not occur in any of the exposed ultramafic rocks. However, Scoates (1972) observed calcite in joints and in the central parts of serpentine veinlets at the Gordon Lake Mine. Abundant calcite stringers and calcite-filled slips and shears were intersected in peridotite in a diamond-drill
hole at the Werner Lake West Arm occurrence (Assessment file 52L07NW E-2 (A-4, B-1); DDH
1971-17).
A common characteristic of the ultramafic rocks is the presence of symmetric, mono- or bimineralic, metasomatic, contact alteration or reaction zones. These zones occur along the margins of the
ultramafic pods and in alteration halos adjacent to pegmatite dikes and peraluminous pegmatoid veins
that intrude the ultramafic rocks (Scoates 1972). The reaction zones of large ultramafic pods surround
a serpentinized but relatively unaltered core, however, unaltered cores are absent in smaller pods. The
outer contact reaction zones consist of coarse-grained, variably chloritic biotite selvages that range
from a few centimetres to 1.5 m thick and are developed between the ultramafic rocks and the felsic
country rocks. The outer biotite zones are formed by high temperatures of metasomatism or addition
of K2O from adjacent country rocks with high K2O contents (Bowes et al. 1964; Fowler et al. 1981).
Peridotite pods also host marginal biotite-garnet zones at the Alcock-Mosher A and A1 showings and
the Norpax prospect at Almo Lake (Assessment files 52L06NE N-1 and R-1); at the Dome No.3 occurrence on Werner Lake (Assessment file 52L07NW D-3); and at the Frederick No.1 occurrence on
Rex Lake (Assessment files 52L07NE Q-1 and Q-2).
Detailed work by Scoates (1972) has shown that the biotitic outer zones have a sharp contact with
an inner zone of medium- to coarse-grained amphibole that grades into the serpentinized ultramafic
mineral assemblage. The amphibole zones range from a few centimetres to 2 m thick (Scoates 1972)
and may have formed by the addition of alumina from felsic country rocks (Fowler et al. 1981; Curtis
and Brown 1969). A talc zone may occur between the amphibole zone and the serpentinized ultramafic rock. Sulphide minerals may be disseminated along the biotite zone-amphibole zone interface
10
(Scoates 1972). Similar contact reaction zones or “blackwall zones” have been documented in metamorphosed ultramafic rocks by numerous workers including Bowes et al. (1964), Curtis and Brown
(1969), Erslev (1980), Fowler et al. (1981), Fox and Van Berkel (1988), Loferski (1986), Peltonen
(1995), Sanford (1982) and Springer (1974).
Scoates (1972) studied chemical variation between the unaltered centre and the altered margin of
the A-peridotite at the Gordon Lake Mine and found that there was a general increase in SiO2, Al2O3,
CaO, Fe2O3, Na2O, K2O, MnO and TiO2 and a decrease in MgO and FeO from the centre to the margin of the ultramafic pod. Scoates (1972) noted significant additions of Na2O and K2O in the marginal ultramafic rocks. Curtis and Brown (1969), Fowler et al. (1981) and Loferski (1986) have documented similar geochemical variations in other metamorphosed ultramafic rocks. In general, contact
reaction zones or “blackwall zones” are interpreted to have formed by the migration of silica, alumina
and potassium from the country rocks into the ultramafic rocks (Fowler et al. 1981; Curtis and Brown
1969) with the exchange of magnesium from the ultramafic rocks into the country rocks. Magnesium
is released during serpentinization of the ultramafic rocks and commonly causes chloritization of surrounding country rocks (Cerny 1968).
Some ultramafic rocks in the study area show enriched Rb and K2O values, such as those in samples 94JRP-1069 (71.7 ppm Rb, 1.82% K2O) and 94JRP-1078 (9.8 ppm Rb, 0.24% K2O) (Tables 12
and 15). The Rb and K2O enrichments are due to the addition of Rb and K (in biotite) to the ultramafic rocks during the intrusion of pegmatite dikes, peraluminous pegmatoid and associated metasomatism.
In summary, the development of contact reaction zones is due to recrystallization of ultramafic
rocks by a combination of metasomatic and metamorphic reactions between the ultramafic rocks,
felsic country rocks, pegmatites and peraluminous intrusive rocks. An attempt to establish equilibrium between diverse rock compositions resulted in chemical interaction between the ultramafic and
felsic rocks (Erslev 1980; Loferski 1986; Scoates 1972; Springer 1974). The extreme compositional
diversity between the 2 rock types prevented the formation of hybrid rocks with intermediate compositions (Scoates 1972).
REE (rare earth elements) patterns (Figure 6) define 2 distinct suites of ultramafic cumulate rocks
situated along the Werner--Rex lakes fault.
The lower ultramafic suite is characterized by 23.3 to 27.5% MgO, 0.10 to 0.43% TiO2,
11830-56210 ppm Cr (average 36715 ppm Cr), 447-6000 Ni (average 2473 ppm Ni), <5-664 ppb Pd,
<10-166 ppb Pt, 4-8 ppm Y and 7-17 ppm Zr with Zr/Y = 1.8-2.4 and low total REE abundances
(Tables 12, 13 and 15). The lower ultramafic suite contains 6.26 to 10.28% Al2O3; 13.86 to 40.33%
SiO2; and 0.76 to 5.04% CaO (see Table 12) with CaO/Al2O3 = 0.07 - 0.49. Chondrite-normalised
REE are generally 1 to 2 times chondrites and define patterns that are weakly concave with slightly
enriched light REE and slightly depleted heavy REE (see Figure 6). The heavy REE patterns show
distinct troughs from Gd to Tm that may be due to heavy REE partitioning into primary igneous amphibole. The REE patterns also have variable, moderate to strong negative Eu anomalies (Eu/Eu* =
0.3-0.8) that indicate preferential mobility of Eu2+ during serpentinization and recrystallization (Sun
and Nesbitt 1978; Frey 1984). An ultramafic pod on the north shore of Rex Lake (see Table 13; sample 94JRP-1039) is an exception because it has a distinctive bowl-shaped REE pattern, a weak positive Eu anomaly (Eu/Eu* = 1.2) (see Figure 6), low Cr values (ie: 166 ppm Cr) and generally lower
total REE abundances than other rocks in the suite. A spider diagram with mantle-normalised REE
and trace element patterns (Figure 7) shows a variable trough at Nb and slight enrichment of light
REE.
The upper ultramafic suite is characterized by 16 to 23.4% MgO, 0.26 to 0.41% TiO2,
2602-36400 ppm Cr (average 10111 ppm Cr), 1124-6700 ppm Ni (average 3359 ppm Ni), 88-746 ppb
Pd, 25-143 ppb Pt, 9-10 ppm Y, and 18-23 ppm Zr with Zr/Y=1.8-2.5 (see Tables 12 and 15). The
upper ultramafic suite contains 7.34 to 10.64% Al2O3; 29.13 to 40.97% SiO2; and 4.24 to 7.82% CaO
(see Table 12) with CaO/Al2O3 = 0.40 - 0.92. The upper ultramafic suite has relatively low total REE
contents that are slightly enriched compared to the lower suite. Chondrite-normalised REE are 2.5 to
4 times chondrites and define relatively flat patterns with slightly enriched light REE and depleted
heavy REE with distinct troughs from Gd to Tm (see Figure 6). The REE patterns display an inconsistent Eu anomaly (Eu/Eu* = 0.7-1.5) that varies from weak negative to weak positive (see Figure 6).
11
The fact that both positive and negative Eu anomalies occur in similar samples from the same suite of
rocks suggests that the Eu anomalies are due to mobility of Eu2+ during hydrous alteration of olivine
and pyroxene producing serpentine or tremolite-chlorite assemblages (Sun and Nesbitt 1978; Frey
1984; Barnes et al. 1988). A spider diagram with mantle-normalised REE and trace elements (see
Figure 7) shows a general enrichment of light REE and a distinct trough at Nb.
A comparison of the geochemical characteristics for the two suites suggests that the upper ultramafic suite is more evolved than the lower ultramafic suite. This observation is supported by a general
increase of CaO, K2O and Na2O concentrations and a corresponding decrease in MgO and Fe2O3 from
the lower to the upper suite (see Table 12). Average Al2O3 content is generally consistent and ranges
from 7.7 to 8.0% from the lower to upper suite, respectively. A few Al2O3 values are greater than
10% in rocks from both suites. The increase in the CaO/Al2O3 ratio from the lower to upper suite (see
above) is due to a significant increase in CaO (see Table 12). Most samples from the two suites show
essentially the same type of REE patterns on the chondrite-normalised and primitive mantle-normalised diagrams (see Figures 6 and 7). Consistent differences in total REE abundance within and between the 2 suites are consistent with progressive fractional crystallization. The enrichment in light
REE and the pronounced trough at Nb, a characteristic of both ultramafic suites, is a distinctive signature for all magmas that have been contaminated by crustal rocks (Wilson 1989). Inconsistent and
variable positive and negative europium anomalies between similar samples in a single suite of rocks
is indicative of europium mobility during hydrous alteration and serpentinization of ultramafic rocks
(Sun and Nesbitt 1978; Frey 1984; Barnes et al. 1988).
Geochemical data for ultramafic rocks are provided in Tables 12 to 15 and 16 to 19, inclusive.
Mafic Rocks
Narrow lenses and layers of gabbroic rocks are spatially associated with ultramafic pods and are distributed along the Werner--Rex lakes fault and associated fault splays at Seal, Almo, Gordon, Werner,
Rex, Bug and the Fortune lakes. Outcrops of ultramafic and gabbroic rocks occur together although
contacts between the two rock types were not observed. Numerous discontinuous, isolated bodies of
gabbro are concordant with lithologic layering in the metasedimentary migmatite assemblage.
Gabbros at Almo, Gordon and Werner lakes are non-magnetic, dark grey-black, moderately to
strongly foliated and fine- to medium-grained with a granoblastic, granular, recrystallized texture.
The primary igneous mineralogy and textures of the gabbros have been modified, obscured and replaced by a mineral assemblage of dark green hornblende; recrystallized plagioclase; and variable
amounts of biotite. Dark green hornblende may occur as large, 1 cm porphyroblasts in a fine-grained
plagioclase matrix. The gabbros are weakly to moderately altered with variably chloritized amphibole
and biotite; variably sericitized feldspar; and aggregates of tremolite and clinozoisite.
The gabbros include small (3 cm x 1 cm) foliation parallel lenses of coarse-grained, black-dark
green amphibole and small pods and lenses of ultramafic rock. The gabbros may contain diffuse or
discontinuous alternating layers defined by variations in grain size, texture and mineral content, such
as: granoblastic plagioclase-rich bands alternating with lepidoblastic bands of black or dark green amphibole. Porphyritic gabbro, at Almo Lake and the Rexora No.3 prospect, hosts white-pale green,
subhedral, plagioclase phenocrysts that range in abundance (3 to 15%) and grain size (1 to 9 cm). A
gabbro, at the Radioactive Minerals occurrence on Rex Lake, contains 25 to 80% disseminated and
semi-massive magnetite and is the only magnetite-bearing gabbro identified in the study area. A diamond-drill hole (Assessment file 52L07NE R-1, DDH FO-4) intersected 1 to 5 cm thick magnetite
layers in the gabbro with some layers up to 100 cm thick. This gabbro also contains coarse, diffuse,
pegmatitic patches composed of plagioclase + orthopyroxene + amphibole + biotite. The pegmatitic
patches may be rimmed with dark amphibole selvages.
Foliation parallel pegmatoid and granitic pegmatite dikes intrude the majority of gabbros; have
irregular contacts; and are generally less than 1 m thick. The pegmatoid is most common and consists
of chalky white plagioclase + biotite + quartz with plagioclase commonly embedded in a biotite matrix. The pegmatoids have thick (1 to 20 cm) biotite selvages or alteration halos at their contacts. The
biotite selvages were formed by the addition of K2O to the gabbroic wall rocks from the pegmatoid
dikes. Biotite alteration commonly invades the gabbro along discrete foliation planes and becomes
12
more diffuse away from the margins of the pegmatoid dikes. The granitic pegmatite consists of pink
potassic feldspar, quartz and minor biotite. Granitic pegmatite dikes may have biotite selvages and
moderate to strong, pervasive, epidote alteration halos extending for several metres from the contacts.
Gabbros are always epidotized adjacent to granitic pegmatite.
Leucogabbro or anorthositic gabbro occurs as large, discontinuous lenses at Rex, Bug and Fortune
lakes where it is associated with ultramafic pods and other gabbroic rocks. The leucogabbro is distributed along the Werner--Rex lakes fault and associated fault splays but is not as widely distributed in
the metasedimentary migmatite assemblage as the ultramafic rocks and other gabbros. Leucogabbro
was not identified in the study area west of Rex Lake.
Leucogabbro is commonly massive and very coarse-grained with a distinctive chalky white or
grey weathered surface. It dominantly consists of large, recrystallized crystals of white plagioclase
with medium- to coarse-grained interstitial amphibole + biotite and orthopyroxene + clinopyroxene +
biotite in granulite grade rocks. The leucogabbro may host interlayered granulitic lenses or pods composed of plagioclase + orthopyroxene + clinopyroxene + quartz. Total mafic mineral content in the
leucogabbro rarely exceeds 20%.
The leucogabbro at Bug Lake is massive to strongly foliated and occurs as a thin, discontinuous,
arcuate unit that extends along the east margin of the Gone Lake pluton. The leucogabbro is variably
epidotized with epidote in veins; on fractures; and in clots and pods. The leucogabbro is closely associated with mafic gneiss, however, contacts between these 2 rock types were not observed. A contact
between leucogabbro and metasedimentary migmatite was observed southeast of Bug Lake, unfortunately, the contact is sheared and folded. Intrusive contacts between the leucogabbro and the Gone
Lake pluton are exposed at Bug Lake. Leucogabbro xenoliths occur within the margin of the Gone
Lake pluton at Bug and Rex lakes.
The leucogabbro at Rex Lake is variably foliated and closely associated with ultramafic pods and
gabbro. It is intruded and strongly epidotized by pink pegmatite dikes and peraluminous, garnetiferous pegmatoid. At one location, on the north shore of Rex Lake, the leucogabbro contains a metamorphosed alteration assemblage that consists of abundant (70%) disseminated cordierite porphyroblasts
(< 2 cm in size) and 5% fine-grained garnet porphyroblasts that replace previously altered feldspar.
Abundant biotite and accessory hercynite accompany the cordierite-garnet assemblage. The alteration
is situated at a contact between the leucogabbro and peraluminous diatexite. Large (2 m x 1.5 m) foliated and folded enclaves of leucogabbro occur within the north margin of the Gone Lake pluton at
Rex Lake. An outcrop of foliated leucogabbro, also on the north shore of Rex Lake, contains narrow
bands or layers of coarse-grained, dark green-black amphibole and magnetite. These ultramafic layers
may represent original igneous layers of pyroxene within the leucogabbro.
A large body of leucogabbro, associated with ultramafic pods and other gabbroic rocks, is located
southwest of Upper Fortune Lake. This body has been affected by granulite grade metamorphism and
is very coarse-grained, variably deformed and intruded by pink pegmatite dikes, plagioclase + biotite
+ quartz pegmatoid and peraluminous, garnetiferous pegmatoid. Fine- to medium-grained sections of
leucogabbro are completely recrystallized with a distinct granular or sugary texture.
The gabbros are characterized by 44.3 to 49.5% SiO2, 7.27 to 15.7% Al2O3, 6.5 to 12.0% MgO,
0.53 to 1.25% TiO2, 131-864 ppm Cr, 64-343 ppm Ni, 13-28 ppm Y and 18-72 ppm Zr with Zr/Y =
1.27-2.8 (see Tables 1, 2, 3, 4, 5 and 7). Chondrite-normalised REE are 10 to 12 times chondrites
and define relatively flat patterns with enriched light REE and depleted heavy REE with weak troughs
from Gd to Tm (Figure 8). The REE (rare earth element) patterns display inconsistent Eu anomalies
that vary from weak negative to weak positive (see Figure 8) and indicate possible Eu2+ mobility during alteration (Sun and Nesbitt 1978). A spider diagram of gabbros with mantle-normalised REE and
trace elements (Figure 9) shows enrichment of light REE and a pronounced trough at Nb indicative of
crustal contamination of the parent magma. Two samples (see Table 5; 94JRP-1015 and 94JRP-1026)
from a gabbro on the north shore of Rex Lake show anomalous light and heavy REE enrichment and
negative Eu anomalies (see Figure 8) that may also be an effect of intense alteration associated with
the intrusion of felsic dikes or sills.
The leucogabbro or anorthositic gabbro is characterized by 41.9 to 48.9% SiO2, 23.3 to 28.8%
Al2O3, 2.1 to 4.9% MgO, 0.10 to 0.26% TiO2, 70-546 ppm Cr, 90-183 ppm Ni, 2.1-7.4 ppm Y, 17-24
13
ppm Zr with Zr/Y = 2.7-8.1 (see Tables 1 to 7, inclusive) and low LREE/HREE ratios such as (La/
Lu)N = 0.96-13.23. Chondrite-normalised REE define steeply sloping patterns with light REE enrichment, flat or strongly depleted heavy REE, moderate to strong positive Eu anomalies and REE abundances that vary from 10 to 20 times chondrites (Figure 10). The positive Eu anomalies indicate that
the leucogabbros are cumulates with Eu partitioning into plagioclase (Cullers and Graf 1984). Depletion of heavy REE in sample 94JRP-1041(see Figure 10 and Table 5) may be due to strong alteration
metamorphosed to a cordierite-biotite-garnet assemblage. Depletion of heavy REE in sample
93JRP-119 (see Figure 10 and Table 2) may be due to strong deformation and associated chloritization
of mafic minerals. A spider diagram with mantle-normalised REE and trace elements (Figure 11)
shows enrichment of light REE and a pronounced trough at Nb except for sample 94JRP-1041 which
is strongly altered. As mentioned above, the trough at Nb is indicative of crustal contamination of the
parent magma.
Geochemical data for the gabbros are presented in Tables 1 to 3 and 4 to 7, inclusive.
Boudinaged, discontinuous and metamorphosed mafic dikes/sills intrude the mafic gneiss and
metasedimentary migmatite at Bug Lake. The majority of the dikes are less than 1 m wide, mediumgrained and dark green-brown or green-grey with an unusual mottled coloration on weathered surfaces. The dikes are commonly foliation parallel but several dikes transect foliation and layering in the
country rocks. The dikes are composed of amphibole, biotite and orthopyroxene and may contain
pale-green fibrous, felted masses of tremolite and chlorite. Some dikes have unusual gradational contacts with the country rocks while others have sharp contacts with reaction selvages. Several dikes
have thick, fine-grained margins with coarse-grained cores.
Relationship between Ultramafic and Mafic Rocks
The mineralogy, textures and geochemistry of ultramafic-mafic intrusive rocks at Werner–Rex–Bug
lakes are characteristic of plutonic intrusions that have been modified by alteration and metamorphism. Although most primary igneous textures have been obscured some possible remnant mineral
layering has been recognized in the gabbro and leucogabbro. Mineral layering in ultramafic pods has
been documented by the author; by Scoates (1972); and by Falconbridge Ltd. (Assessment file
52L07NE R-1). Magnetite layers in gabbro and chromite layers in peridotite were documented by
Falconbridge Ltd. at Rex Lake (Assessment file 52L07NE R-1). The close spatial association between olivine-orthopyroxene-chromite cumulates, gabbro, porphyritic gabbro and leucogabbro/anorthosite suggests that these rocks may have evolved from the same magma source. This inference is
supported by chemical trends and variations, such as:
1) Ultramafic-mafic rocks have the same general trends in their REE patterns (see Figures 6 to
11) such as enriched light REE, depleted heavy REE and a pronounced trough at Nb
suggesting that the gabbro and ultramafic rocks evolved from a single magma
contaminated by crustal material (Wilson 1989).
2) Major element analyses plotted on ternary diagrams of CaO-MgO-Al2O3 and
Fe2O3-MgO-Al2O3 (Figure 12) show a well developed, continuous fractionation trend
from ultramafic rocks to leucogabbro or anorthositic gabbro.
3) The ultramafic-mafic rocks show continuous compositional variations in most major, trace
and rare earth elements, such as: a general depletion of MgO associated with corresponding
enrichments in Al2O3, SiO2, Na2O, K2O and CaO from ultramafic to anorthositic rocks
(Figure 13); enrichment of incompatible trace and rare earth elements (ie: Ti, Zr, Y and La)
with decreasing MgO (Figure 14); and depletion of compatible trace elements such as Ni, Cr
and Co with decreasing MgO (Figure 15).
These chemical trends are consistent with early fractional crystallization and accumulation of olivine, orthopyroxene and chromite that would have advanced the evolution of the magma towards MgO
depletion and Al2O3, SiO2, Na2O and CaO enrichment (Lesher and Arndt 1995; Yang et al. 1995).
Subsequent fractionation of plagioclase and pyroxene from the magma formed gabbro, leucogabbro
and anorthosite. Therefore, the ultramafic-mafic rocks may have been part of a single stratiform intrusion that evolved from a single magma source..
Most chromite ores in stratiform intrusions occur in ultramafic rocks with olivine, orthopyroxene
and chromite as cumulus minerals (Duke 1983) which is characteristic of chromite-bearing ultramafic
14
rocks at Werner--Rex--Bug lakes. Results of sulphur isotope studies for massive breccia ore at the
Gordon Lake Mine (Scoates 1972) confirm a magmatic origin of the sulphide ores and show that the
sulphur is “indigenous to the ultramafic rocks” and may represent “unaltered mantle sulphur”.
Scoates (1972) recognized that the ultramafic rocks at Gordon Lake resembled differentiates of a stratiform mafic intrusion and concluded that the ultramafic rocks and associated sulphide mineralization
were products of fractional crystallization from a single tholeiitic magma source. Blackburn and Vogg
(1988) suggested that the ultramafic pods were originally part of mafic-ultramafic, sill-like intrusions
that were faulted and boudinaged subsequent to their emplacement.
STRUCTURAL GEOLOGY
Foliations
A dominant, regional, east-striking foliation occurs throughout the study area and consists of a combination of parallel, planar structural features, such as: compositional layering; stromatic layering;
grain size variation; and preferred orientation of platy minerals in metasedimentary migmatite, mafic
gneiss and syn-tectonic intrusive rocks. The foliation is vertical or steeply dipping to the north but
may dip steeply south in close proximity to the Werner--Rex lakes fault. Localized deflection of the
foliation around the east margin of the Gone Lake pluton was observed at Bug Lake where the foliation strikes north to north-northwest and dips moderately to the east. Breaks (1991) cautions that a
distinction between S1 and S2 foliations within the English River Subprovince cannot be made with
confidence on a regional scale and that the dominant regional foliation is,“ best regarded as a composite of bedding (S0 ), S1 and S2”. Therefore, the foliation referred to in this report is a combination of
planar tectonic elements. The S2 foliation was only recognized locally where it is axial planar to D2
folds.
An east-northeast-striking, vertical, S2 mineral foliation is axial planar to tight folds at Rex and
Almo lakes. At Bug Lake, an east-striking, vertical to north-dipping, axial planar S2 foliation is associated with gentle open folding. Quartz-feldspar leucosome has been intruded along the S2 foliation at
Almo, Rex and Bug lakes and is consistent with observations (Breaks 1991) that the S2 fabric has controlled the emplacement and orientation of peraluminous granitic leucosome in many parts of the English River Subprovince.
Small tectonic, elliptical, winged inclusions (Hanmer and Passchier 1991) of ultramafic rock, in
metasedimentary migmatite north of Bug Lake, are commonly lozenge-shaped or “fish-shaped” with
their long axes oriented within the angular range 900 < α < 1800. These inclusions can be used as
shear sense indicators (Hanmer and Passchier 1991) and, in almost all cases at Bug Lake, display a
sinistral shear sense.
Lineations
Mineral and slickenside lineations are poorly developed in the study area where planar structural features dominate over linear features. Lineations occur locally along the Werner--Rex lakes fault at
Almo Lake and trend west-northwest or west-southwest with subhorizontal or shallow west-plunges.
West-northwest- and northwest-trending mineral and slickenside lineations with shallow west-plunges
were also mapped along the Werner--Rex lakes fault at Reynar Lake (Beakhouse 1997). Mineral lineations along the north shore of Rex Lake are northeast-trending with moderate to shallow east and
northeast plunges. Mineral lineations at Bug Lake are southeast-trending with consistent moderate
plunges to the east and southeast.
Folds
Folding of the metasedimentary migmatite assemblage and mafic gneiss is common throughout the
study area but is best developed along the north shore of Rex Lake where dominant, tight, S-style
symmetric folds with east-northeast-striking axial planar foliations (S2) plunge moderately to the
northeast and east-northeast. Many of these folds contain asymmetric, second-order, parasitic folds
along their limbs. Mafic and ultramafic intrusions on the north shore of Rex Lake are also affected by
this folding. The east plunge of folds is a consistent structural feature observed throughout the major15
ity of the English River Subprovince and is related to the regional D2 deformation (Breaks 1991).
Beakhouse (personal communication, 1994) observed interference folds in metatexite, on the northeast
shore of Rex Lake, where possible D1 folds are refolded by D2 folds. Beakhouse (1997) also mapped
an east-striking anticlinal fold axis at the west end of Rex Lake.
Small Z- and S-drag folds (Z-styles dominate over S-styles) with east and northeast-striking axial
planes are common throughout the metasedimentary migmatite assemblage north of the Werner--Rex
lakes fault. The folds have shallow west- to northwest-plunges west of Gordon Lake and shallow
east- to northeast-plunges east of Gordon Lake. This folding may be related to deformation along the
Werner--Rex lakes fault or may be a combination of D2 folding and post-D2 fault-related folding. At
Bug Lake, small Z- and S-drag folds (Z-styles dominate over S-styles) with north-striking axial planes
are common as well as small open folds with east-striking axial planes and moderate to shallow east
plunges.
Faults
The Werner--Rex lakes fault is a regional-scale, generally west-striking, vertical to steeply north-dipping structure that transects the English River Subprovince and extends for more than 30 km from the
Manitoba--Ontario provincial boundary to Rex Lake. The fault is subparallel to the English River
Subprovince boundary and separates tonalite-trondhjemite-granodiorite batholiths to the south from
the metasedimentary migmatite assemblage in the north (see Figure 3). The fault is less than 6 m
wide at Almo, Gordon and Werner lakes but is enclosed within an approximately 1 km wide transpressive zone of brittle-ductile deformation consisting of very highly strained and variably mylonitized
metasedimentary migmatites, mafic gneiss, granitoid/pegmatoid rocks and ultramafic-mafic intrusive
rocks. Scoates (1972) observed the fault in underground exposures at the Gordon Lake Mine and described it as a 0.3 to 4.5 m wide band of chlorite schist with horizontal to subhorizontal slickenside
lineations.
Ultramafic pods distributed along the length of the fault are described (Scoates 1963; Carlson
1958) as north dipping, northwest-plunging, pipe-shaped bodies that are elongated in an easterly direction and have a greater vertical than lateral extent. The geometry of the ultramafic pods and the shallow west plunge of mineral and slickenside lineations and Z-drag folds along the Almo–Gordon lakes
portion of the Werner--Rex lakes fault is evidence for transpressive dextral sense of shear along the
fault with north-side up displacement to the east.
The Werner--Rex lakes fault “horsetails” or breaks up into several first and second order splays at
the east end of Werner Lake (see Figure 3 and Map P.3315–Revised, back pocket). A major south
splay strikes southeast from Werner Lake through to Rex Lake and is coincident with the contact between the Marijane batholith and the metasedimentary migmatite assemblage. At Rex Lake the south
splay strikes east-northeast and extends through the metasedimentary migmatite assemblage (see Figure 3 and Map P.3317--Revised, back pocket). At Bug Lake a north to north-northwest-striking fault
extends along the east contact of the Gone Lake pluton. A north splay strikes east from Werner Lake
through Loon’s Nest Lake to Upper and Lower Fortune lakes (see Figure 3 and Map P.3316--Revised,
back pocket) and transects the metasedimentary migmatite assemblage. In the west, the Werner--Rex
lakes fault strikes west-southwest from Almo Lake and extends south of Reynar Lake through to Davidson Lake (Carlson 1958).
Northeast- and northwest-striking crossfaults have been interpreted to transect the Werner--Rex
lakes fault in the vicinity of the Norpax prospect at Almo Lake and at the Werner Lake cobalt mine
(Carlson 1958). There is little evidence to confirm the presence of these faults other than coincident
topographic depressions, however, Scoates (1972) observed crossfaults in underground exposures at
the Gordon Lake Mine that transect the Werner--Rex lakes fault and ultramafic-mafic rocks within the
fault. Some retrograde metamorphism is related to the late crossfault structures (Scoates 1972).
Narrow (< 1m) east-striking mylonite bands and shear zones occur within metasedimentary migmatite and all granitoid rocks. These structures are sub-parallel to the Werner--Rex lakes fault and are
probably related to post-D2 deformation along the fault.
Minor, narrow, dextral and sinistral strike-slip faults striking northeast and northwest are distributed north and south of the Werner--Rex lakes fault. These are relatively late-tectonic brittle-ductile
structures.
16
METAMORPHISM
Amphibolite Facies
Metamorphic grade within the metasedimentary migmatite assemblage increases from amphibolite to
dominantly granulite grade from west to east across the study area (Figure 16). The area from Almo
Lake to Werner Lake has been affected by regional amphibolite grade metamorphic conditions. The
author was unable to identify any discrete contact metamorphic effects imposed by various individual
intrusions due to the overprinting of regional metamorphism; extensive migmatization; retrograde alteration; and poor exposure of contacts between rock types. The north contact of the Marijane batholith and the east and north contacts of the Gone Lake pluton are strongly deformed and bounded by
faults, therefore, contact metamorphic aureoles imposed by these intrusions are difficult to recognize.
Mineral assemblages characteristic of regional amphibolite grade metamorphism are best observed
in metasedimentary migmatite and mafic intrusive rocks at Almo, Gordon and Werner lakes. Metamorphosed gabbroic rocks are granoblastic and consist of relatively unaltered prograde mineral assemblages of plagioclase + dark green hornblende + brown biotite with relatively weak retrograde alteration to actinolite-tremolite, clinozoisite, chlorite and sericite. The paleosome of the metatexitic metasedimentary migmatite is composed of granoblastic, recrystallized quartz + feldspar + brown biotite +
red poikilitic garnet (almandine) porphyroblasts. Garnet content can exceed 80% of the paleosome, as
in outcrops near the tailings dam on the west shore of Gordon Lake, and is commonly accompanied
by biotite + magnetite + cordierite. Minor, small, cordierite and orthopyroxene porphyroblasts were
observed in some garnetiferous metatexite at Almo and Gordon lakes and may represent small areas of
locally higher metamorphic conditions.
Ultramafic rocks were initially affected by hydration to serpentine during initial cooling which
was followed by regional amphibolite grade metamorphism and associated zonal metasomatism. This
was followed by a period of relatively high-temperature, retrograde serpentinization resulting in the
formation of antigorite (Scoates 1972; Whittaker 1986; Winkler 1976) which overprints prograde mineral assemblages.
Granulite Facies
Granulites are anhydrous, coarse-grained, granular, orthopyroxene-bearing metamorphic rocks formed
at high temperatures and pressures of the granulite facies. Granulites are produced by specific metamorphic conditions, resulting from anomalous crustal thickening and heating episodes, that affected
limited portions of the crust during limited periods of time (Newton 1986). Granulite grade metamorphism consists of pressure-temperature controlled solid-state dehydration of rocks that includes infiltration of external CO2-rich fluids, possibly from the mantle, which may induce dehydration and
metasomatism (Passchier et al. 1990; Pattison 1991). Dehydration reactions lead to the growth of anhydrous orthopyroxene, after hydrous amphibole, and the progressive decrease in the modal abundance of biotite. Orthopyroxene is formed by reactions between biotite and quartz; hornblende and
quartz; biotite, sillimanite and quartz; or hornblende, garnet and quartz (Winkler 1976; Holt and
Wightman 1983; Newton 1986). The amphibolite-granulite metamorphic boundary is defined by the
first appearance of orthopyroxene (hypersthene) which is the definitive granulite mineral (Winkler
1976; Newton 1986).
Low-pressure (0.4 to 0.6 GPa), high temperature (770oC or more) regional granulite grade metamorphism affected parts of the English River Subprovince between 2692 Ma and 2660 + 20 Ma
(Breaks 1991) during the emplacement of the granite-granodiorite suite and the peraluminous granitoid suite. The majority of rocks in the east part of the study area have been affected by granulite
metamorphism. Granulitic rocks are distributed in small lens-shaped zones less than1 km long and
300 m wide at Loon’s Nest and Upper Fortune lakes; or as larger, more extensive areas at Lower Fortune, Rex and Bug lakes (Figure 16). The granulitic rocks are spatially associated with faults and fault
splays which suggests that CO2-rich fluids passed from the mantle into the upper crustal rocks along
these permeable fault structures. Abundant granulitic rocks are also distributed around the north and
east margin of the Gone Lake pluton. The pluton contains orthopyroxene-bearing charnockitic rocks
(Breaks 1991) commonly restricted to granulite grade metamorphic zones (Condie and Allen 1984;
17
Kramers and Ridley 1989). Granulite grade rocks are commonly cordierite-rich and intermixed with
amphibolite grade rocks and migmatites. These are characteristic features of some transitional zones
between upper amphibolite and granulite terranes (Dallmeyer 1972; Newton 1986; Pattison 1991; Nijland 1993). Country rocks commonly host crosscutting or foliation parallel veins and patches of anhydrous, granulite mineral assemblages. The granulite grade rocks are granoblastic to gneissic, medium- to coarse-grained, massive to strongly foliated and composed of relatively fresh prograde mineral assemblages of iron-magnesium-aluminium silicates such as orthopyroxene, clinopyroxene, almandine garnet, cordierite, potassium feldspar, plagioclase, hercynite + remnant biotite and hornblende.
Typical field and mineralogical features of the granulites in the study area are:
1) Presence of cordierite, almandine garnet, magnetite + biotite and the absence of prograde
muscovite.
2) Orthopyroxene is commonly confined to mafic and intermediate rocks and is less
common in felsic, quartz-rich rocks.
3) Presence of associated anorthositic rocks and rocks with charnockitic affinities such as the
Gone Lake pluton (Breaks 1991).
4) The presence of peraluminous leucosome veins and patches with anhydrous mineralogy,
such as: orthopyroxene + cordierite + feldspar + biotite + quartz; orthopyroxene +
cordierite + feldspar + garnet + biotite + quartz; orthopyroxene + garnet + quartz +
feldspar; and orthopyroxene + feldspar +quartz.
Granulitic wacke and interlayered pelitic rocks are typically coarse grained and consist of quartz,
feldspar, reddish-brown biotite, disseminated magnetite, abundant red almandine garnet, blue-purple
cordierite and rare orthopyroxene. Garnet is commonly intergrown with coarse biotite and occurs as
thick concentrations in large irregular patches or layers. Individual garnet porphyroblasts appear as
disseminated, subhedral crystals (up to 3 cm in diameter) that are packed with inclusions and rimmed
with mafic-depleted halos of plagioclase and quartz. The garnet content can range from less than 5 to
90% of the paleosome, however, garnet content and crystal size is highly variable from layer to layer
within the paleosome.
Granulitic anorthositic gabbro, gabbro and ultramafic rocks are composed of variable amounts and
combinations of orthopyroxene, clinopyroxene, plagioclase, hornblende, biotite-phlogopite, hercynite,
magnetite, cordierite and garnet. The majority of gabbros at Rex and Fortune lakes have been affected
by upper amphibolite to granulite grade metamorphism and are recrystallized, medium- to coarsegrained and weakly to strongly deformed without any preserved igneous textures. These gabbros contain a secondary mineral assemblage of orthopyroxene + clinopyroxene + plagioclase + amphibole +
biotite and may contain interstitial quartz and some rare interlayered granulitic lenses composed of
plagioclase + orthopyroxene + clinopyroxene + quartz. Similar granulite grade metagabbros have
been documented in the Grenville Subprovince (Pattison 1991).
The strongly deformed and recrystallized granulite grade leucogabbro at Upper Fortune Lake is
intermixed with more mafic gabbroic phases in complex, chaotic textures that suggest mobility, plastic
deformation and contortion due to partial melting. Some sections of leucogabbro have brecciated or
net-veined appearances with orthopyroxene + clinopyroxene + amphibole concentrated in a network of
narrow, criss-crossing, discrete veins in white, recrystallized, plagioclase-rich rock. Plagioclase + orthopyroxene + clinopyroxene veins were also noted. Similar textures have been described (Pattison
1991) in granulite grade metagabbros in the Grenville Subprovince and are interpreted to result from a
combination of metasomatism, dehydration and partial melting of the gabbros during granulite metamorphism.
Granulitic mafic gneiss consists of a mineral assemblage of magnetite + plagioclase + brown
hornblende + biotite + orthopyroxene + cordierite + garnet. The granulitic mafic gneiss hosts abundant, coarse (0.5 to 2 cm), blocky, subhedral, black-dark brown orthopyroxene porphyroblasts with
mafic-depleted halos of plagioclase. Abundant, coarse-grained biotite and large cordierite and red garnet porphyroblasts commonly accompany the orthopyroxene. Garnet content and crystal size is notably smaller in the granulitic mafic gneiss compared to the metasedimentary migmatite. The cordierite
occurs in narrow (<1 m) foliation parallel layers or in fine- to medium-grained, patchy aggregates that
18
include orthopyroxene + plagioclase + quartz + garnet + biotite. Cordierite may also occur as large
(< 1 to 4 cm in diameter) subhedral, indigo-blue crystals disseminated throughout the mafic gneiss.
Cordierite content may exceed 50% with local concentrations up to 90%.
Coarse orthopyroxene + cordierite + biotite + plagioclase + K-feldspar + magnetite + garnet rocks
intruded by cordierite + plagioclase + orthopyroxene + biotite leucosome veins are distributed in irregular, discontinuous pods and layers along the north shore of Rex Lake and at the Perkins and North
occurrences at Bug Lake. The orthopyroxene-cordierite rocks are almost always associated with ultramafic and mafic intrusive rocks. The orthopyroxene-cordierite-dominated assemblage is indicative of
low pressure conditions during granulite metamorphism (Passchier et al. 1990; Riccio 1981).
The orthopyroxene-cordierite rocks at Bug Lake are characterized by 42.4 to 49.8% SiO2, 12.1 to
15.1% Al2O3, 11.2 to 13.8% MgO, 0.63 to 0.86% TiO2, 6-23.4 ppm Y, 98-142 ppm Zr with Zr/Y =
4.8-20.8 while similar rocks at Rex Lake are characterized by 43.1 to 57.5% SiO2, 14.4 to 17.4%
Al2O3, 5.9 to 15.2% MgO, 0.57 to 1.22% TiO2, 13-21 ppm Y, 57-133 ppm Zr with Zr/Y = 3.2-10.2
(Tables 1, 2, 16, 17 and 19). Some of the orthopyroxene-cordierite rocks also have high chromium,
nickel and copper values such as sample 95JRP-1053 (see Table 18). The general bulk chemistry of
the rocks suggests that the protolith was dominantly mafic. Chondrite-normalised REE define steeply
sloping patterns with light REE enrichment, depleted heavy REE with variable patterns, weak to moderate positive and negative Eu anomalies and REE abundances that vary from 10 to 300 times chondrites (Figure 17). Several REE patterns in Figure 17 are similar in appearance to REE patterns for
ultramafic and gabbroic rocks in the study area (see Figures 6 and 8), especially sample 94JRP-1059
(see Table 17), which has a REE pattern that is identical to ultramafic rocks in the upper ultramafic
suite. Pan and Fleet (1996) have shown that enriched light REE and variable Eu anomalies in granulitic rocks are most likely effects of alteration, metasomatism and REE mobility during granulite
metamorphism. Many rocks contain REE-rich accessory minerals such as zircon, monazite and apatite, which may explain the enrichment of light REE.
Orthopyroxene + cordierite + plagioclase + K-feldspar + garnet rocks have been documented in
southwestern Oregon where they have been interpreted as metagabbros (Foose 1986). Amphibole +
spinel + magnetite + orthopyroxene hornfelses as well as cordierite + anthophyllite hornfelses in New
South Wales, have also been interpreted as metasomatized and metamorphosed mafic and ultramafic
rocks (Irving and Ashley 1976). Reinhardt (1987) has documented dolerites (diabase) that have been
converted to massive cordierite rocks in metasedimentary gneisses in Queensland, Australia.
Geochemical data for the orthopyroxene-cordierite rocks are tabulated in Tables 1, 2, 3 and 16 to
19, inclusive.
Hercynite, a green iron-rich spinel, commonly occurs in cordierite-rich granulite grade mafic
rocks as well as some of the orthopyroxene-cordierite rocks. The presence of hercynite in cordieritebearing rocks is typical of very high temperatures under low to medium pressure metamorphic conditions (Passchier et al.1990). A single outcrop of an unusual massive, dark grey, fine- to mediumgrained apatite + feldspar + biotite + cordierite + hercynite rock is located on the north shore of Bug
Lake. The rock contains up to 75% hercynite, low silica (29.87% SiO2), very high alumina (36.47%
Al2O3 ) and relatively high phosphorous (1.2% P2O5) (see Table 1, sample 93JRP-92; see Figure 4).
The outcrop has a curious brecciated texture with dark grey-green, subrounded hercynite-rich pods or
nodules in a white-weathering plagioclase-rich matrix. A large irregular patch of diffuse, disseminated biotite was also observed in the outcrop. Chondrite-normalised REE from the hercynite-rich
rock defines a steeply sloping pattern with light REE enrichment, depleted heavy REE and a moderate
negative Eu anomaly (see Figure 4). The REE pattern is similar to other REE patterns from mafic
gneiss at Rex and Bug lakes (see Figure 4).
The highest grade pelitic rocks in the English River Subprovince contain hercynite enveloped by
cordierite suggesting temperatures of 7500C (Breaks 1991). Calcsilicate rocks at Loon’s Nest Lake
contain hercynite coexisting with calcite and forsterite. This mineral assemblage is also indicative of
high temperature metamorphism (Passchier et al. 1990).
19
ALTERATION
The abundance of cordierite + orthopyroxene + garnet-rich mineral assemblages in granulite grade
metasedimentary migmatite and mafic gneiss at Rex and Bug lakes was initially described as possible
metamorphic equivalents of pre-metamorphic, chloritic alteration (Parker 1993, 1994; Beakhouse
1993, 1994). It was postulated that the abundance of aluminosilicate minerals may represent some
type of metamorphosed alteration associated with sedimentary exhalative (SEDEX) sulphide deposits.
However, alteration associated with SEDEX-type deposits dominantly consists of tourmalinization,
silicification, siderite alteration and chlorite-albite-pyrite alteration (Morganti 1981; Leitch and Turner
1994) and evidence for these alteration types was not identified in the study area. The possibility that
cordierite + orthopyroxene + garnet-bearing rocks are granulite grade equivalents of cordierite + orthoamphibole + garnet assemblages found in metamorphosed, amphibolite grade, hydrothermal, seafloor alteration zones associated with volcanogenic massive sulphide (VMS) deposits is also unlikely.
Several observations suggest that the cordierite + orthopyroxene + garnet-bearing rocks are not high
grade equivalents of cordierite + orthoamphibole assemblages and do not represent pre-metamorphic
alteration, these are:
1)
2)
3)
4)
5)
6)
7)
8)
Unusual and anomalous bulk compositions, consisting of large silica and alkali mass losses
and corresponding iron and magnesium mass gains typical of VMS-associated
hydrothermal alteration (Barrett and MacLean 1994), are not obvious in the bulk
chemistry of rocks at Rex and Bug lakes.
There is no spatial or genetic correlation between the abundance of cordierite +
orthopyroxene + garnet-bearing rocks and the occurrence of sulphide mineralization. The
majority of mineral occurrences in the study area consist of original or remobilized magmatic
sulphide mineralization that is not accompanied by hydrothermal alteration.
The absence of metavolcanic rocks and lack of evidence for any volcanic activity in the
study area suggests that the cordierite + orthopyroxene + garnet-bearing rocks were not
derived from a synvolcanic, seafloor alteration assemblage or volcanic protolith.
No examples of amphibolite grade cordierite + orthoamphibole-bearing rocks were
identified in the study area.
Cordierite is commonly poikilitic and does not show any evidence of recrystallization.
Grains of remnant hornblende are present in orthopyroxene but remnant orthoamphiboles
(ie: anthophyllite, gedrite) were not identified.
Accessory gahnite (zincian spinel) and sphalerite were not identified in the
orthopyroxene-cordieriterocks. Gahnite is a common constituent of cordierite +
orthoamphibole rocks associated with copper-zinc VMS-deposits at Manitouwadge
(James et al. 1978); in Finland (Schreurs and Westra 1985); and in South Africa (Spry 1987).
Various combinations of cordierite, orthopyroxene, biotite and garnet occur in
metamorphosed alteration assemblages in syn-tectonic intrusive rocks such as:
anorthositic gabbro; and tonalite-trondhjemite-granodiorite rocks of the Marijane
batholith and Gone Lake pluton.
The above observations, especially point 8, suggest that alteration occurred during metasomatism
and metamorphism after the intrusion of the Gone Lake pluton and Marijane batholith but before peak
regional metamorphism. In general, the bulk chemistry of cordierite-bearing rocks at Rex and Bug
lakes does show weak to moderate reduction in alkalis, due to the alteration of feldspar, and moderately elevated MgO content compared to cordierite-poor equivalent rock types. As described previously,
the presence of cordierite is a function of the magnesium content of the host rocks (Dallmeyer 1972).
Magnesium migration from ultramafic-mafic rocks into the surrounding country rocks during pre-peak
metamorphic serpentinization (Cerny 1968) may explain the elevated MgO content and cordierite
abundance in the country rocks. The introduction of magnesium results in the formation of chlorite in
the country rocks (Cerny 1968) which forms cordierite during high grade metamorphism. Also, many
of the rocks containing orthopyroxene and cordierite are interpreted to be derived from magnesium-rich serpentinized and metasomatized mafic gneiss and mafic or ultramafic rocks.
The compositions of orthopyroxene + cordierite + garnet-bearing rocks from Rex and Bug lakes
have been plotted on an AFM diagram (Figure 18). The compositions of the majority of rocks lie in
20
the field defined by cordierite + orthoamphibole rocks derived from altered volcanic protoliths as
compiled by Reinhardt (1987). High grade orthoamphibole-bearing rocks associated with VMS-deposits at Manitouwadge also plot within the cordierite + orthoamphibole field (Zaleski et al.1995).
The AFM diagram illustrates that although orthopyroxene + cordierite-bearing rocks do not represent
pre-metamorphic alteration they do show chemical characteristics that are similar to altered volcanic
rocks, such as elevated MgO and reduced alkalis.
Granitic rocks at the margins of the Marijane batholith and Gone Lake pluton display small outcrop-scale areas of alteration. The alteration occurs in areas of granulite metamorphism and includes:
disseminated cordierite and garnet porphyroblasts in irregular patchy areas (Marijane batholith; Werner Lake); cordierite + garnet veins and diffuse orthopyroxene + magnetite patches (Marijane batholith;
Rex Lake); and garnet + biotite + magnetite + cordierite in narrow foliation parallel veins (Gone Lake
pluton; Bug Lake). Abundant cordierite with biotite, hercynite-spinel and minor garnet also occurs in
strongly foliated anorthositic gabbro adjacent to peraluminous diatexite (Rex Lake). Similar types of
alteration have been documented in other granulite terranes (Pattison 1991) and are interpreted to have
formed during dehydration and metasomatism of the host rocks by the infiltration of carbon dioxiderich fluids during high grade metamorphism. Quartzofeldspathic veins containing variable amounts of
garnet, cordierite, orthopyroxene and biotite are common throughout the granulite grade country
rocks. Similar veins in granulites have been documented by Pattison (1991) in the Grenville Subprovince and are considered to have formed during dehydration and associated metasomatism of the
country rocks.
As described previously, ultramafic rocks have been affected by two periods of hydrous alteration:
1) an early serpentinization that resulted in the replacement of mafic silicate minerals by serpentine
minerals; and 2) a late, high temperature retrograde serpentinization resulting in the replacement of
prograde metamorphic minerals by antigorite. The ultramafic rocks were also affected by prograde
metamorphism, metasomatism and associated intrusion of felsic intrusive rocks that resulted in the
formation of marginal, mono- or bimineralic contact reaction or “blackwall” zones. These zones were
formed by an exchange of elements between the felsic and ultramafic rocks in an attempt to establish
equilibrium between the two rock types.
Potassic alteration halos adjacent to pegmatoid veins and dikes/sills commonly consist of biotitic
selvages along the edges of the veins or biotitization of the country rocks. Medium- to coarse-grained
biotite extends outwards from the veins along foliation planes in the country rocks until it becomes
diffuse and fades away. Granitic pegmatite dikes are accompanied by epidote alteration haloes that
extend for several metres from the margins of the dikes. Epidote alteration on late fractures is also
common adjacent to the Gone Lake pluton and late-tectonic granite-granodiorite intrusions.
Late retrograde sericitization and chloritization is localized along fractures, on foliation surfaces
and in narrow mylonite zones and is associated with late movements along the Werner--Rex lakes fault
and other fault structures in the study area.
Alteration associated with cobalt sulphide mineralization is described in the “Mineralization” section of this report. No significant alteration is associated with magmatic sulphide mineralization in
the ultramafic rocks. Minor retrograde chloritization and some possible, localized silicification is associated with remobilized sulphide mineralization.
21
Mineralization
Detailed descriptions of each mineral deposit in the study area are presented in Appendix 1 and their
locations are indicated on 6 maps in the back pocket of this report. The following descriptions of
mineralization types in the study area is a summary or overview of some of their major characteristics.
MAGMATIC MINERAL DEPOSITS
Nickel-Copper Sulphide Mineralization
Variable amounts of magmatic nickel-copper sulphide mineralization (Scoates 1972) are confined to
serpentinized, metamorphosed, metasomatized and recrystallized ultramafic pods distributed throughout the Werner--Rex--Bug lakes area. Gabbroic rocks host minor, disseminated and patchy copper sulphide mineralization at the Gordon Lake Mine and at the Radioactive Minerals occurrence at Rex
Lake.
There are two types of sulphide mineralization in the study area: 1) disseminated nickel-copper
sulphide mineralization in ultramafic rocks; and 2) remobilized magmatic sulphide mineralization.
The majority of information regarding these types of sulphide mineralization at the Gordon Lake Mine
has been summarized from Scoates (1972).
DISSEMINATED SULPHIDE MINERALIZATION
Two types of disseminated sulphide mineralization have been identified and described by Scoates
(1972) at the Gordon Lake Mine 1) disseminated diffuse mineralization and 2) disseminated interstitial mineralization. These two sub-types are described below.
Disseminated, diffuse sulphide mineralization consists of 5 to 15% total sulphide minerals in recrystallized and altered ultramafic pods. It is the most common style of mineralization in the study
area. Fine-grained, subhedral to anhedral, sulphide mineral grains with ragged, irregular, grain boundaries occur in: 1) irregular, patchy, unevenly distributed disseminations; 2) in narrow (< 1 cm), discontinuous, sulphide stringers; and 3) in delicate “net textures” (Scoates 1972). Scoates (1972) noted
that sulphide grains at the Gordon Lake Mine commonly have globule or droplet shapes. Sulphide
minerals are also disseminated along hairline fractures; on foliation partings; and at contacts between
biotite-amphibole marginal zones and less altered serpentinized cores within the ultramafic pods. Sulphide minerals dominantly consist of pyrrhotite and chalcopyrite with minor pentlandite, cubanite and
violarite (Scoates 1963, 1972). Pentlandite is always closely associated with pyrrhotite. Cubanite
occurs as inclusions in chalcopyrite and pentlandite (Scoates 1972).
Disseminated, interstitial sulphide mineralization occurs in relatively unaltered cores of ultramafic
pods. Sulphide minerals are medium-grained and commonly interstitial to amphibole and orthopyroxene with little evidence for sulphide replacement of silicate minerals (Scoates 1972). Pyrrhotite is the
most common sulphide mineral and is commonly intergrown with pentlandite. Scoates (1972) reported that pyrrhotite is also interstitial to chromite grains and may occur as small inclusions in the
chromite. Chalcopyrite occurs as irregular, discrete grains or in patches associated with pyrrhotite and
pentlandite. Magnetite grains commonly occur along the rims of the sulphide minerals (Scoates
1972). Analyses of disseminated interstitial sulphide ores from the A-peridotite orebody, at the Gordon Lake Mine, gave numerous, low to moderate Rh, Pd and Pt values. The highest values that were
reported are: 0.23 ounce rhodium per ton; 4.40 ounces palladium per ton and 0.34 ounce platinum per
ton (Scoates 1963, Table 40, p.150).
Very little disseminated interstitial sulphide mineralization was observed by the author since the
majority of ultramafic pods are altered, recrystallized and contain diffuse sulphide minerals. Coarsegrained ( < 1 cm) interstitial pyrrhotite was observed at the Rexora No.3 and 4 occurrences and interstitial chalcopyrite and pyrite was identified at the Radioactive Minerals occurrence at Rex Lake.
Grab samples of disseminated sulphide mineralization, collected by the author, from exposed mineralized ultramafic pods in the study area, analyzed between less than 5 and 1145 ppb Pd (average 309
22
ppb Pd); less than 10 and 425 ppb Pt (average 85.6 ppb Pt); 104 to 378.1 ppm Co (average 173 ppm
Co); 0.004 to 0.67% Ni (average 0.23% Ni); 0.01 to 4.4% Cu (average 0.38% Cu); and 55.1 to 278
ppm Zn (average 127.3 ppm Zn) (see Tables 14 and 18).
REMOBILIZED SULPHIDE MINERALIZATION
Remobilized, brecciated sulphide mineralization (Scoates 1972) was encountered at the Norpax prospect and Gordon Lake Mine and consists of discontinuous, linear, sinuous, bands of semi-massive sulphide minerals. The remobilized breccia zones are parallel to the Werner--Rex lakes fault.
The B-breccia zone at the Gordon Lake Mine is situated 3 to 12 m south of the fault and is
approximately 600 m long in the upper levels of the mine; 90 m long on the 1650-level; and has a vertical dimension of 400 m (Scoates 1972). Therefore, the B-breccia zone has a crude wedge-shape in
longitudinal section with the apex pointing downward (Scoates 1972). Scoates (1972) describes the
B-breccia zone as a series of discontinuous breccia sulphide zones ranging in width from a few centimetres to 3 m. The zone is foliation parallel and conformable with enclosing gneissic rocks and has
sharp and distinct contacts that are marked by thin biotite selvages in the wall rocks. The B-breccia
zone transects the A-peridotite orebody and terminates at the bottom of the A-peridotite. Tongues of
massive sulphide protrude from the peridotite into the B-breccia zone (Scoates 1972). The B-breccia
zone also has a close spatial association with pegmatite dikes. The zone truncates pegmatite dikes and
is also intruded by pegmatite. The pegmatites commonly host disseminated sulphide mineralization
(Scoates 1972).
The B-breccia zone is dominantly composed of pyrrhotite, pentlandite and chalcopyrite with minor pyrite, marcasite, molybdenite and cassiterite. The sulphide minerals are variably distributed
throughout the zone. The breccia ore does not contain magnetite; has more abundant pentlandite; and
more abundant pyrite than the disseminated ore (Scoates 1972). The breccia ore displays a well-developed ball-texture consisting of rounded and subrounded to subangular fragments of a wide variety
of rocks types embedded in a sulphide matrix. Fragments dominantly consist of granodiorite to quartz
diorite and range from a few millimetres to 4 cm in size. Amphibolite and pegmatite inclusions are
0.6 m to 0.9 m long and 0.3 m to 0.6 m wide (Scoates 1972). This texture is indicative of solid-state
sulphide remobilization that results from the detachment, fragmentation, rolling and grinding of wall
rock and brittle sulphide minerals in a ductile sulphide groundmass (Plimer 1987). The ball-texture is
similar to a protomylonite which is defined as a coherent crush-breccia composed of greater than 50%
megascopically visible fragments separated by finely ground material (Higgins 1971). Lenses of massive sulphide in the A and G peridotite pods at the Gordon Lake Mine also display mineral textures
that are similar to the B-breccia zone.
The average composition of massive sulphide ore in the B-breccia zone is: 37.93% S, 6.99% Ni,
0.08% Cu and 55.0% Fe (Scoates 1972). Analyses of the sulphide ores from the B-breccia zone gave
numerous high Rh, Pd and Pt values such as: 0.97 ounce rhodium per ton; 6.96 ounces palladium per
ton and 2.74 ounces platinum per ton (Scoates 1963, Table 40, p.150).
Remobilized, brecciated sulphide mineralization at the Norpax prospect also occurs within a linear
zone parallel to the Werner--Rex lakes fault. The zone was reported to be 3 to 8 m wide with a strike
length of about 200 m (Carlson 1958). Sulphide mineralization consists of semi-massive to disseminated pyrrhotite, pentlandite, chalcopyrite, pyrite and violarite (Carlson 1958). The semi-massive sulphide minerals have a well developed, strong, ball-texture consisting of rounded fragments of wall
rock (tonalite, pegmatite, ultramafic rock) embedded in a groundmass of fine-grained pyrrhotite. The
sulphide minerals are also remobilized and injected along fractures and thick veins. Sulphide minerals
are hosted in strongly biotitic, amphibolitized mafic and ultramafic rocks and late biotite-feldsparquartz pegmatite dikes. Sulphide mineralization intersected in diamond-drill core (Assessment files
52L06NE N-1, R-1) is described as: 2 to 10% disseminated chalcopyrite and pyrrhotite in biotitic
rocks and peridotite; and seams of pyrrhotite and pentlandite in biotite gneiss. Pegmatite dikes were
reported to host disseminated chalcopyrite (Assessment file 52L06NE N-1, R-1).
Underground development work at the Norpax prospect indicated that mineralization had an average grade of 1.32% Ni and 0.85 % Cu on the 250-foot level and an average grade of 1.23% Ni and
0.99% Cu on the 375-foot level (Carlson 1958). Grab samples from the waste rock dump analyzed as
high as 7000 ppb Pd and 210 ppb Pt (Blackburn et al. 1988).
23
Seams, zones or veins of remobilized massive and ball-texture sulphide mineralization occurs in
ultramafic rocks at Rex and Bug lakes. The ball-texture veins consist of rounded fragments of silicate
minerals and wall rock in a pyrrhotite-pyrite-rich groundmass. More massive sulphide veins consist
of anhedral polycrystalline aggregates of chalcopyrite and pyrite with minor pyrrhotite. The chalcopyrite-rich veins have narrow chloritic alteration halos and commonly occur where ultramafic rocks have
been intruded by pegmatite dikes. Sulphide mineralization is also commonly remobilized along fractures and foliation surfaces and disseminated within the pegmatites. Minor, disseminated molybdenite
was observed on fractures and foliation surfaces in ultramafic rocks adjacent to pegmatite dikes. Disseminated molybdenite also occurs with pyrite in narrow biotitic shear zones in ultramafic rock at the
Radioactive Minerals occurrence on Rex Lake.
One to 4 cm thick remobilized sulphide veinlets and narrow mineralized zones consisting of greater than or equal to 25% combined chalcopyrite, pyrite and minor molybdenite are hosted by biotitic,
amphibolitized ultramafic rocks at the North occurrence at Bug Lake. The veinlets and zones are foliation parallel but may also transect foliation as narrow extension veins. Some veins contain elongate,
fibrous amphibole crystals with a constant preferred orientation that is perpendicular to the vein walls.
Mineral fibres with preferred orientations are common in extensional veins and indicate vertical opening of the veins (Robert et al. 1994). The majority of the veins are discontinuous, folded and strongly
deformed. Chalcopyrite appears to have migrated outwards from the veins and is intergrown with silicate minerals. Grab samples, collected by the author, from remobilized sulphide veins at the North
occurrence analyzed from 0.74 to 12.3% Cu (average 3.8% Cu); 84.2 to 1304 ppm Ni (average 653
ppm Ni); 143 to 266 ppm Co (average 189 ppm Co); 17 to 650 ppm Mo (average 341.2 ppm Mo);
169 to 568 ppb Au (average 308.5 ppb Au); and 3 to 22 ppm Ag (average 9.3 ppm Ag) (see Table 3).
Metal ratio and sulphur isotope work by Scoates (1963, 1972) demonstrated an “intimate genetic
relationship” between the remobilized sulphide ores in the B-breccia zone and the disseminated interstitial sulphide mineralization in the A-peridotite orebody at the Gordon Lake Mine. Scoates (1972)
considered the sulphur in the B-breccia zone to be “indigenous to the ultramafic rocks” and “magmatic in origin”. This indicates that the B-breccia zone consists of original magmatic sulphide mineralization that was reconstituted and remobilized from ultramafic host rocks during alteration, metamorphism, deformation and intrusion of felsic rocks. The sulphide mineralization experienced mineralogical changes; lost its primary form; and migrated into structurally controlled zones parallel to the
Werner--Rex lakes fault. Felsic intrusive rocks contributed molybdenite and cassiterite to the remobilized sulphide mineral assemblage. The abundance of pyrite and marcasite in the B-breccia zone may
also be due to alteration of pyrrhotite to pyrite during remobilization (Panayiotou 1980; Peltonen
1995). The same processes affected the sulphide mineralization at the Norpax prospect and the mineral occurrences at Rex and Bug lakes. Similar remobilized magmatic nickel-copper sulphide mineralization has been documented in deformed, altered and metamorphosed ultramafic-mafic intrusive
rocks in Finland (Peltonen 1995; Papunen et al. 1979).
Chromite Mineralization
Chromite mineralization occurs in variable amounts in almost all of the ultramafic pods at Almo, Gordon, Werner and Rex lakes. The chromite is difficult to recognize on irregular weathered surfaces but
is easily identified in slabbed samples. The chromite commonly occurs in thick (4 to 8 cm), widely
spaced, remnant layers with irregular boundaries. The chromite layers are separated by ultramafic
rock hosting disseminated chromite or small, irregular chromite patches. A 0.5 m thick, massive
chromite layer in peridotite was intersected in a diamond-drill hole at the Radioactive Minerals occurrence at Rex Lake (Assessment file 52L07NE R-1; DDH FO-4). Chromite layers are composed of 50
to 90% closely spaced to tightly packed cumulus chromite grains intergrown with interstitial altered
olivine, orthopyroxene or amphibole. Chromite occurs as fine-grained (< 0.1 mm to 0.5 mm),
rounded, anhedral to subhedral grains that are partially altered to magnetite. Magnetite occurs along
the rims of chromite grains and in transecting magnetite veinlets. Stowe (1994) reported that subsolidus exchange during cooling, serpentinization and metamorphism of the ultramafic rocks may also
modify original chromite composition. Scoates (1972) determined that the composition of chrome
spinels in the A-peridotite at the Gordon Lake Mine, “ lie in the general field of picotites”. Picotite is
a dark brown, chromium-bearing variety of hercynite (an iron spinel).
24
Grab samples, collected by the author from the majority of ultramafic pods in the study area, analyzed between 166 ppm Cr and 2.7% Cr (average 7757 ppm Cr) and 0.01 and 8.03% Cr2O3 (average
2.65% Cr2O3). The highest chromium values were obtained at the Rexora No.5 prospect at Werner
Lake (see Tables 12, 14, 16, 18, ).
REMOBILIZED SULPHIDE MINERALIZATION IN MIGMATITE,
PEGMATITE AND GNEISS
This type of sulphide mineralization is copper-rich and hosted within granulite grade gneisses and
felsic intrusive rocks, such as: mafic gneiss; metasedimentary migmatite; orthopyroxene-cordierite
rocks; biotite + garnet + amphibole schists interlayered with migmatite; and pegmatite or peraluminous pegmatoid. The mineralization consists of sulphide veins; disseminated sulphide minerals on
fractures and foliation surfaces; patchy, diffuse, disseminated sulphide minerals; and diffuse or interstitial disseminated sulphide minerals in pegmatite.
The disseminated mineralization is made up of 5 to 15% total sulphide minerals in patchy, irregular sections consisting of fine-grained, subhedral to anhedral grains of chalcopyrite and pyrite with
minor pyrrhotite and molybdenite. Chalcopyrite may form clotty coarse-grained aggregates intergrown with garnet and biotite in diatexite. Disseminated sulphide minerals are also concentrated in
quartz-rich sections of pegmatite and consist of medium- to coarse-grained chalcopyrite and pyrite
interstitial to quartz and feldspar.
Remobilized sulphide veins are identical in mineralogy and form to those that occur in ultramafic
rocks, however, the veins consist of massive, coarse aggregates of chalcopyrite and minor pyrite and
do not exhibit ball-textures. The sulphide veins are foliation parallel and 1 to 15 cm wide. In some
cases, chalcopyrite has migrated outwards from the veins and is disseminated amongst silicate minerals in the wall rocks. Very little alteration accompanies the sulphide mineralization with the exception
of minor chloritization of mafic minerals in the wall rocks and local silicification associated with pegmatite-hosted sulphide mineralization at the Frederick occurrences at Rex Lake.
Remobilized sulphide mineralization also occurs in migmatites and gneisses at the Sogemines and
Stratmat occurrences at Upper and Lower Fortune lakes; at the Bug Lake copper occurrences; and at
the Dome No.1 occurrence at Loon’s Nest Lake. Scoates (1972) described massive lenses of chalcopyrite, 8 mm to 20 cm wide and 3 m long, occurring in horizontal joint sets in metasedimentary migmatite at the Gordon Lake Mine. The migmatite at the mine also hosts small lenticular pods (0.6 m x
0.3 m x 0.3m) of coarse-grained hornblendite containing disseminated pyrite, chalcopyrite, pyrrhotite
and molybdenite (Scoates 1972). Samples collected by the author from remobilized sulphide mineralization at the Bug Lake, Dome No.1, Frederick, Sogemines and Stratmat occurrences analyzed from
8.05 ppm to 12.4% Cu (average 1.6% Cu); less than 40 to 451 ppm Ni (average 118.9 ppm Ni); less
than 5 to 831 ppm Co (average 87 ppm Co); less than 8 to 144 ppm Mo (average 13.7 ppm Mo); less
than 3 to 697 ppb Au (average 132.3 ppb Au); and less than 2 to 19 ppm Ag (average 4.3 ppm Ag)
(see Tables 3, 6, 10 and 18).
The sulphide mineralization has a close spatial association with nearby deformed, altered, granulite grade ultramafic-mafic intrusive rocks that are interlayered with metasedimentary migmatite. Extensive alteration, high grade metamorphism and deformation of the ultramafic and mafic intrusive
rocks, combined with the intrusion of felsic pegmatite dikes, caused remobilization and mineralogical
changes in the original magmatic sulphide mineralization. The copper-rich sulphide mineralization
subsequently migrated into structures within surrounding migmatitic country rocks. Similar remobilized sulphide mineralization has been documented by Peltonen (1995) and Papunen et al.(1979) in
Finland where migmatitic rocks, adjacent to small ultramafic cumulate bodies, host nickel-copper sulphide mineralization.
COBALT-COPPER SKARNOID DEPOSITS
Assemblages of calcsilicate rock with amphibole-rich layers and veins and biotite-garnet schist, at the
Werner Lake cobalt mine, West and East cobalt zones and at Loon’s Nest Lake, are referred to as skarnoid in this report. Table 23 summarizes and compares the characteristics of the skarnoids at Werner
25
and Loon’s Nest lakes. The term skarnoid refers to “skarn-like rocks of uncertain or complex origin”
(Einaudi and Burt 1982) and is a descriptive term for fine-grained, iron-poor, calcsilicate rocks which
reflect the compositional control of the protolith (Meinert 1992). Meinert (1992) states that, “skarnoid
is intermediate between a purely metamorphic hornfels and a purely metasomatic, coarse-grained
skarn.” The mineralogy of skarnoid rocks is not dominated by garnet or pyroxene and, therefore, does
not have the typical mineralogy that defines skarns (Meinert 1992).
Werner Lake Cobalt-Copper Zone
Cobalt-copper sulphide mineralization is erratically distributed within the Werner Lake cobalt-copper
zone: a 1 to 30 m wide, east-striking, deformation zone of mixed lithologies that include stratabound
skarnoid deposits. The cobalt-copper zone extends for a strike length of 4.14 km from the north shore
of Almo Lake to the northwest shore of Werner Lake (Map P.3313–Revised, back pocket) and was
first described by Derry (1931) as a “replacement vein” in a “garnet-rich band which may be traced for
a mile or more along the strike”. The zone hosts the Werner Lake cobalt mine, the West and East zone
cobalt occurrences and some minor showings of disseminated copper sulphide mineralization in ultramafic rocks.
The cobalt-copper zone consists of a linear, sinuous, anastomosing band of strongly foliated biotite-garnet schist intermixed with foliation parallel, granitoid and pegmatoid leucosome veins of
quartz + plagioclase + biotite and quartz + potassium feldspar + biotite + garnet. The leucosome
veins are folded, discontinuous, irregular and strongly contorted in some locations. The biotite-garnet
schist is also interlayered with strongly foliated amphibolitized gabbro, mafic gneiss, metatexite, and
small (0.5 to 2 m in size) pods or boudins of dark green-black, biotitic, ultramafic rock.
The cobalt-copper zone at Almo Lake is enclosed within inhomogeneous, garnetiferous diatexite
with paleosome enclaves of wacke, mafic gneiss, amphibolitized gabbro and biotitic ultramafic rock.
The cobalt-copper zone, enclosed within the diatexite, is barren of sulphide mineralization with the
exception of some minor (5%), fine-grained, disseminated chalcopyrite and pyrrhotite in a small ultramafic pod (see Map P.3313--Revised, back pocket).
The cobalt-copper zone at Werner Lake extends between a granite-granodiorite intrusion to the
south and metatexite to the north (see Map P.3313--Revised, back pocket). The metatexite consists of
moderately to strongly foliated wacke and pelitic paleosome with inclusions of mafic gneiss, amphibolitized gabbro and ultramafic pods. The granite-granodiorite intrusion is buff-grey to pink weathering, massive and porphyritic with potassium feldspar phenocrysts ranging from 1 to 6 cm in size. The
intrusion is foliated along its north margin and contains diffuse pegmatitic phases and scattered xenoliths of wacke and gabbro. The granite-granodiorite contains minor, fine-grained, disseminated pyrite
and is weakly sericitic, chloritic, carbonatized and variably epidotized at the Werner Lake cobalt mine.
The portion of the cobalt-copper zone, adjacent to the granite-granodiorite intrusion, hosts high
grade cobalt-copper sulphide mineralization in lenses and layers of calcsilicate, amphibole-rich layers
and veins and biotite-garnet schist at the Werner Lake cobalt mine and West cobalt zone occurrence.
The intrusion intrudes and cuts off the cobalt-copper zone on the northwest shore of Werner Lake at
the East cobalt zone occurrence (see Map P.3313--Revised, back pocket).
SKARNOID ROCKS
The skarnoid at the Werner Lake cobalt mine and West cobalt zone occurrence is situated at a sheared
intrusive contact with the granite-granodiorite in the footwall (south side) and metatexite in the hanging wall (north side). The intrusive contact is parallel or subparallel to layering in the metatexite and
skarnoid assemblage. Skarn is commonly confined to narrow but vertically extensive zones where
intrusive contacts are subparallel to layering or bedding planes (Meinert 1992), therefore, the skarnoid
at Werner Lake may have similar geometry. Foliation and layering in the skarnoid rocks strike about
2600 and dip steeply north. Size of the skarnoid is difficult to determine due to poor exposure and
excavation during mining, however, the mineralized zone was reported to be 2 to 4 m wide (Wright
1932; Chown 1955; Carlson 1958).
Chown (1955) identified three main rock units in the mineralized zone at the Werner Lake cobalt
mine and West cobalt zone: 1) a marginal biotite-garnet schist or gneiss on the north side of the min26
eralized zone; 2) an amphibolite on the south side of the zone; and 3) a “quartz-poor biotite-feldspar
schist” (mafic gneiss?) that occurs between the biotite-garnet schist and the amphibolite. The “biotitefeldspar” schist was described as the host of the high grade ore (Chown 1955). Biotite-feldspar schist
was not identified by the author, instead, the author found a quartz-poor calcsilicate rock containing
high grade cobalt mineralization. The author identified a marginal biotite-garnet schist along the
hanging wall of the mineralized zone and medium to coarse amphibolite (mafic gneiss?, gabbro?) on
the footwall.
Calcsilicate rocks occur in narrow discontinuous layers and lenses and are pale green-grey, massive, fine- to medium-grained and dominantly composed of white-grey calcite. A subtle layering or
banding can be seen in some of the calcsilicate rocks. The rocks contain a prograde mineral assemblage calcite + forsterite (magnesian olivine) + magnetite + hercynite-spinel that is strongly retrograded to antigorite, chondrodite, clinochlore (magnesian chlorite) and clinozoisite (iron-poor epidote). A few narrow layers of calcite + magnetite + diopside were identified by the author at the West
cobalt zone but diopside was not recognized at the mine. Chondrodite and hercynite were not recognized in the calcsilicate rocks from the West cobalt zone.
In thin section, the rock is granoblastic with large polygonal grains of calcite; radiating patches of
antigorite pseudomorphs after equant olivine; disseminated anhedral magnetite intergrown with calcite
and olivine; minor subhedral green hercynite containing magnetite lamellae and magnetite on rims and
fractures; and rare aggregates of pale yellow chondrodite formed by the alteration of olivine. Antigorite pseudomorphs commonly occur as rosettes with spike-like blades radiating outward from a central
core with fine-grained magnetite rimming the margins of the original olivine or occurring along fractures within the olivine grains. Radiating blades of antigorite may form coronas around partially altered olivine grains. Antigorite also occurs in discontinuous, fracture controlled veins. Narrow discontinuous fracture-controlled veinlets of amphibole, clinochlore and clinozoisite transect the calcsilicate assemblage and are associated with sulphide minerals. The calcsilicate rock displays the characteristics (Einaudi et al. 1991; Mueller et al. 1991) of a skarn-like, high temperature, prograde mineral
assemblage that has been overprinted and retrograded by low-temperature hydrous mineral assemblages (amphibole, clinozoisite, clinochlore) associated with sulphide mineralization.
Large blocks of calcsilicate, in the dump at the mine, contain 8 to 20 cm thick bands or layers of
dark green, very coarse-grained amphibole. In thin section, narrow amphibole veinlets and fractures
transect the calcsilicate rocks. Amphibole layers at the West cobalt zone are foliation parallel and subparallel to the margins of the mineralized zone. The amphibole layers are dense and massive consisting of large (4 cm x 10 cm), euhedral to subhedral, dark green crystals of magnesian hastingsite intergrown with coarse, dark green to black magnesian hornblende and interstitial tremolite, magnetite,
quartz, feldspar, hercynite and sulphide minerals. The amphibole layers are variably retrograded to
clinochlore and clinozoisite. A fine-grained, pale green, 2 to 6 cm wide, metasomatic reaction zone or
alteration front, consisting of clinozoisite + magnetite + clinochlore, occurs at the interface between an
amphibole layer and biotite-garnet schist at the West cobalt zone. Diffuse clinozoisite-clinochlore alteration extends outward from either side of the reaction zone with the most intense alteration in the
biotite-garnet schist. The amphibole layers or veins represent an assemblage of hydrous silicate minerals that overprint the earlier biotite-garnet schist and calcsilicate assemblage.
The marginal biotite-garnet schist is strongly foliated with coarse (up to 2 cm in diameter), red,
subhedral to euhedral porphyroblasts of magnesian almandine garnet embedded in a coarse biotite matrix with minor interstitial quartz. The garnet occurs in clotty aggregates or as disseminated crystals
ranging in abundance from 15 to 95% of the rock. The schist is commonly intruded by foliation parallel granitoid and pegmatoid leucosome and variably altered to clinochlore and clinozoisite associated
with disseminated sulphide mineralization.
All of the rock types described above are variably foliated and deformed. Coarse-grained amphibole layers and calcsilicate rocks at the cobalt mine are massive and do not appear to have a foliation.
Chown (1955) observed drag-folded layers of sulphide mineralization at the cobalt mine. Amphibole
and calcsilicate rocks at the West cobalt zone are strongly deformed and foliated. Some calcsilicate
layers at the West zone also appear to be boudinaged into long discontinuous lenses. Mineralized
lenses at the West zone are reported to plunge 450 to the east in underground exposures (Canmine Resources Corporation, News Release, October 22, 1997).
27
Host rocks at the East cobalt zone consist of a strongly deformed, contorted, mixed assemblage of
strongly epidotized, chloritic, coarse-grained biotite-garnet schist and coarse amphibole. The calcsilicate rocks were not recognized at this occurrence. The rocks contain almost solid layers of massive
magnetite and large garnets up to 3 or 4 cm in size.
MINERALIZATION
Chown (1955) reported that the mineralized zone at the Werner Lake cobalt mine consisted of disseminated sulphide minerals that enclosed small, irregular lenses of massive sulphide mineralization situated on either side of the mineralized zone. Carlson (1958) reported that the largest mineralized lens
at the cobalt mine was 3 m x 1.2 m x 1.5 m in size. Assessment file reports (Assessment File
52L07NW S-1) describe the cobalt and copper sulphide mineralization as “spotty and erratic”. The
assessment reports indicate that the best sulphide mineral lenses were high grade but not more than a
few feet long and under a foot in width (Assessment File 52L07NW S-1). The sulphide lenses are
also described as “stopping and starting suddenly” and “jumping from side to side of the garnetiferous
zone” (Assessment File 52L07NW S-1). Diamond drilling conducted at the cobalt mine by Canmine
Resources Corporation intersected 3 mineralized, en echelon lenses (Canmine Resources Corporation,
News Release, February 23, 1996; W. Ferreira, Canmine Resources Corporation, personal communication, 1996).
All of the skarnoid rocks are variably mineralized with cobaltite, chalcopyrite and pyrite (3 to
15% combined sulphide minerals) but the calcsilicate and amphibole layers contain the most abundant
and highest grade cobalt mineralization with up to 25 or 30% combined sulphide minerals. Cobaltite
is the most abundant sulphide mineral with grain size ranging from < 2 mm to 1 cm. Sulphide minerals in calcsilicate occur in bands or layers (up to 10 cm thick) of disseminated, fine- to coarse-grained,
euhedral to subhedral grains that replace and overprint silicate minerals; invade silicate minerals along
fractures; and replace magnetite. Sulphide minerals also occur along narrow veinlets and fractures
with associated chlorite, clinozoisite and amphibole.
Chalcopyrite, pyrite, pyrrhotite and minor cobaltite are disseminated throughout the amphibole
layers and veins. Sulphide minerals may be interstitial to amphibole or overprint and replace silicate
minerals. Chalcopyrite “corrodes” the edges of amphibole crystals and invades silicate minerals along
fractures. Relatively minor cobaltite, chalcopyrite and pyrite are disseminated in the biotite-garnet
schist (see Tables 20, 21 and 22).
Sulphide mineralization at the East cobalt zone dominantly consists of chalcopyrite (25 to 30%)
and pyrite with minor cobaltite (2 to 5%). The sulphide minerals are concentrated in large, irregular,
coarse aggregates interstitial to amphibole and garnet.
Minor minerals identified in the ores from the Werner Lake cobalt mine are: linneaite
(Co+2Co2+3S4) and siegenite (Ni, Co)3S4 (Rose 1951); sphalerite (Godard 1932); annabergite and hematite (Chown 1955); and minor tetrahedrite and bornite (E.O. Chisholm, Assessment file 52L07NW
M-1). The author identified about 1 to 2%, fine-grained, disseminated molybdenite at the West cobalt
zone.
Mineral textures and relationships suggest that the majority of sulphide and oxide minerals were
deposited after the formation of prograde silicate and carbonate mineral assemblages. The relative
timing of the deposition of sulphide and oxide minerals is described as follows:
1) Late deposition of sulphide minerals is indicated by their partial replacement of prograde
silicate minerals.
2) Magnetite formed towards the end of prograde metamorphism. This observation is
supported by the fact that magnetite is intergrown with prograde silicate and carbonate
minerals but also overgrows and partly replaces hercynite-spinel. Hercynite is considered
to be the earliest hydrothermal oxide mineral.
3) Chalcopyrite and cobaltite overgrow and replace magnetite and occur with chlorite and
amphibole in late fractures and veins.
4) Cobaltite replaces chalcopyrite indicating that cobaltite was one of the last sulphide
minerals to be deposited.
5) Pyrite occurs along fractures and as inclusions in cobaltite suggesting that pyrite
deposition occurred before and after the deposition of cobaltite.
28
The range of values for each element that was analyzed from grab samples, collected by the author, at the Werner Lake cobalt mine are indicated below (see Tables 20, 21 and 22).
Cu
(wt%)
0.18 to
1.9
Ni
(ppm)
<40 to
652
Co
(wt%)
0.20 to
3.6
Au
(ppb)
356 to
1246
Ag
(ppm)
4 to 5
Mo
(ppm)
<8
As
(wt%)
0.01 to
1.9
Cr
(ppm)
65 to 839
Zn
(ppm)
96 to
13000
The range of values for each element that was analyzed from grab samples, collected by the author, at the West cobalt zone are indicated below.
Cu(wt%)
Ni (ppm)
Co
(wt%)
Au
(ppb)
Ag
(ppm)
Mo
(ppm)
As (wt%)
Cr
(ppm)
Zn (ppm)
0.05 to
0.79
<40 to 144
<0.31
23 to
209
2 to 6.2
<8 to
15.57
< 0.006 to
0.24
72 to
750
56.3 to
142.4
The range of values for each element that was analyzed from grab samples, collected by the author, at the East cobalt zone are indicated below.
Cu (wt%)
Ni (ppm)
0.016 to
8.1
<40 to 447
Co
(ppm)
25.7 to
5156
Au
(ppb)
<3 to
1154
Ag
(ppm)
<2 to
11.7
Mo
(ppm)
<8 to
9.15
As
(ppm)
< 6 to
17
Cr
Zn (ppm)
(ppm)
2 to 131 79.04 to
268
Diamond drilling conducted by Canmine Resources Corporation intersected numerous mineralized sections at the Werner Lake cobalt mine, such as: 1.48% Co, 0.27% Cu and 0.03 ounce gold per
ton across 4 m in Lens No.2; 0.29% Co and 0.66% Cu across 7.6 m in Lens No.3; and 0.18% Co and
0.11% Cu across 8 m in Lens No.3 (Canmine Resources Corporation, News Release, February 23,
1996). Diamond drilling by Canmine Resources at the West cobalt zone intersected numerous mineralized sections, including: 0.85% Co and 0.31% Cu across 17.27 m in DDH J-40 (Canada Stockwatch, December 13, 1995); 0.06% Co and 0.14% Cu across 9 m in DDH J-9; 0.31% Co, 0.5% Cu,
0.11 ounce gold per ton and 0.12 ounce silver per ton across 8.72 m in DDH J-10; and 0.17% Co,
2.29% Cu, 0.036 ounce gold per ton and 0.39 ounce silver per ton across 4.56 m in DDH J-12 (Canmine Resources Corporation, News Release, October 5, 1995).
Loon’s Nest Lake Zone
The copper sulphide mineralization at Loon’s Nest Lake is hosted within a narrow, linear, discontinuous, east-striking zone composed of the same lithologies found in the Werner Lake cobalt-copper
zone. The Loon’s Nest Lake zone extends along the north shore of Loon’s Nest Lake and consists of a
highly strained assemblage of granulite grade biotite-garnet schist interlayered with small ultramaficmafic pods and skarnoid rocks. The zone is located 100 m north of the fault-bounded contact of the
Marijane batholith. The zone is situated between massive homogeneous diatexite to the north and metatexitic metasedimentary migmatite to the south. The metatexite contains up to 30% porphyroblastic
garnet and is interlayered with orthopyroxene-bearing mafic gneiss. The metatexite is intruded by
thick, massive, pink weathering, granodioritic dikes with potassium feldspar phenocrysts and gabbro
xenoliths.
The Dome No.1 and No.2 copper occurrences are located along the Loon’s Nest Lake zone.
The Dome No.1 is a 1 to 2 m wide unit of coarse biotite-garnet schist containing 25 to 40% garnet
porphyroblasts and 15% disseminated magnetite. The schist is interlayered with a fine-grained, dark
29
green ultramafic rock hosting minor garnet porphyroblasts. Calcsilicate skarnoid rocks were not observed at this occurrence.
The Dome No.2 occurrence consists of calcsilicate skarnoid rocks that are almost identical to the
rocks at the Werner Lake cobalt mine and the West cobalt zone. The skarnoid at the Dome No.2 occurrence is located at an intrusive contact with a thick granodioritic, potassium feldspar megacrystic
intrusive body in the footwall of the occurrence.
SKARNOID ROCKS
Calcsilicate skarnoid rocks do not occur at the Dome No.1 occurrence, therefore, this occurrence is not
discussed in this section.
Calcsilicate skarnoid rock at the Dome No.2 occurrence is pale grey, massive, medium-grained
and dominantly composed of white-grey calcite. Broken rock pieces at the occurrence contain coarse
calcite crystals that are several centimetres in size. The calcsilicate unit is pod-shaped and about 2 m
wide. The rock contains a prograde mineral assemblage calcite + forsterite + hercynite-spinel + tremolite + magnetite (5-30%) that is weakly retrograded to antigorite. In thin section, the rock is granoblastic with large polygonal grains of calcite; minor fibrous patches of antigorite and magnetite along
rims and fractures in equant olivine grains; disseminated anhedral magnetite grains intergrown and
interstitial with calcite and olivine; large subhedral green grains of hercynite intergrown with calcite
and containing magnetite lamellae and magnetite on rims and fractures; and aggregates and individual
acicular crystals of tremolite. The calcsilicate rock is transected by 1 to 3 cm wide actinolite-tremolite
veins. The calcsilicate rock at Loon’s Nest Lake represents a skarn-like, high temperature, prograde
mineral assemblage overprinted by layers and veins of hydrous silicates such as amphibole.
The calcsilicate rock is interlayered with a massive, dark green-black, fine- to medium-grained
ultramafic rock consisting of magnesian hastingsite, tremolite, disseminated magnetite, minor quartz
and small lenses of black magnesian hornblende. This rock is moderately to strongly altered with
large irregular patches of pale green, fine-grained, disseminated clinozoisite and clinochlore.
MINERALIZATION
Mineralization at the Dome No.1 occurrence consists of a seam or vein of 3 to 5% combined chalcopyrite and pyrite in biotite-garnet schist. Disseminated chalcopyrite also occurs in fine-grained amphibolite and replaces and overgrows silicate minerals. Individual grains of chalcopyrite are rimmed
by chlorite and chalcopyrite is disseminated along narrow chlorite veinlets that transect prograde silicate minerals.
Mineralization at the Dome No.2 occurrence consists of about 1 to 5% combined, fine-grained,
disseminated chalcopyrite and pyrite hosted in calcsilicate rocks. Chalcopyrite replaces magnetite and
amphibole and occurs along fractures in olivine and amphibole. Chalcopyrite is also interstitial to
large amphibole crystals. Magnetite appears to have been the last oxide mineral to form in the calcsilicate rock. The magnetite is intergrown and interstitial with prograde silicate and carbonate minerals
but also overgrows and replaces earlier formed hercynite-spinel. The amphibole rocks contain large,
thick aggregates or patches of coarse chalcopyrite (up to 35%) as well as disseminated chalcopyrite.
These observations indicate that chalcopyrite was deposited after the prograde mineral assemblage had
formed.
Grab samples, collected by the author at the Dome No.1 occurrence analyzed up to 34 ppb Au,
219 ppm Cr, 90.4 ppm Co, 64 ppm Ni, 2315 ppm Cu and 119 ppm Zn. Grab samples collected at the
Dome No.2 skarnoid occurrence analyzed between less than 3 and 634 ppb Au; 4 and 11 ppm Ag; less
than 8 and 22.61 ppm Mo; less than 6 ppm As; 24 to 89 ppm Cr; 39.8 to 375 ppm Co; less than 40 to
190 ppm Ni; 0.01 to 6.5% Cu; 45.4 to 201 ppm Zn (see Tables 20, 21 and 22).
Diamond drilling by Dome Exploration at the Dome No.2 occurrence intersected 1.85%Cu across
4.5 feet in DDH No.9; 4.13% Cu across 3.5 feet in DDH No.10; and 2.09% Cu across 9 feet in DDH
No.11 (Assessment file 52L07NW D-3).
Classification of the Skarnoid Deposits
Copper and iron skarns are distinguishable from gold skarns by their high metal ratios, including
Cu:Au, and the good correlation between Cu and Au values (Ray and Webster 1995). Ettlinger and
30
Ray (1989) proposed a method of differentiating gold skarns from gold-bearing copper and iron skarns
based on their Cu:Au and Cu:Ag ratios. A plot of Cu:Au versus Cu:Ag for data from the Werner Lake
-- Loon’s Nest lakes skarnoids (see Table 21; Figure 19) shows that the majority of points plot within
the iron skarn field with most Cu:Au values between 11 000 and 100 000. There is good correlation
between Cu - Au and Ag - Au (Figures 20 and 21) which is typical of iron skarns (Ray and Webster
1995). There is fair correlation between Cu and Ag and good correlation between Co and Au (see
Figures 20 and 21) and poor correlation between Au, Ag, Cu and the other metals.
The skarnoids at Werner and Loon’s Nest lakes can be classified as iron skarns based on their metal ratios and metal correlations. The skarnoids can also be classified further as magnesian iron skarns
based on the magnesium-rich nature of the main silicate minerals and the presence of abundant disseminated magnetite. The disseminated magnetite is characteristic of magnesian iron skarns, because
the silicate minerals do not contain much iron, and the available iron in solution forms magnetite rather than iron silicate minerals such as andradite garnet or hedenbergite pyroxene (Meinert 1992; Einaudi et al. 1981).
31
Discussion
GENESIS OF THE WERNER--REX--BUG LAKES STRATIFORM
INTRUSION
Carlson (1958) and other workers (Chown 1955; Lawson and Zuberec 1987) have suggested that the ultramafic pods at Werner--Rex lakes are small, late intrusions or “pipe-like feeders” emplaced into pre-existing fault structures. Several observations, listed below, do not support this contention:
1) There is no evidence of contact metamorphic aureoles in the country rocks and gabbros
adjacent to the ultramafic pods. This indicates that the pods are not late intrusions.
2) The presence of chromite layers and absence of country rock xenoliths within the pods
indicate that they are not late, “pipe-like feeders”.
3) Many of the ultramafic pods occur as isolated bodies or tectonic inclusions in
metasedimentary and peraluminous granitoid rocks indicating that their emplacement
was not entirely controlled by pre-existing faults.
It’s also unlikely that the ultramafic pods represent “Alpine-type peridotites” (obducted ophiolites)
or mantle diapirs. Alpine-type peridotites are podiform, deformed and fault-bounded ultramafic bodies that lack well developed contact metamorphic aureoles (Jackson and Thayer 1972; Duke 1983) and
are associated with characteristic rock types such as harzburgite, dunite, wehrlite, ultramafic tectonites, sheeted diabase dikes, pillow basalts and thin pelagic marine sediments (Stowe 1994; Duke
1983). Some ultramafic pods at Werner--Rex--Bug lakes are fault-bounded and variably deformed but
many are not. Most of the pods contain well-developed contact metasomatic reaction zones and none
of the pods are associated with the other rock types commonly found with ophiolites. The ultramafic
pods at Werner--Rex--Bug lakes also exhibit features that are rare or absent in Alpine-type peridotites
such as an association with anorthositic rocks and the presence of chromite layers; fine-grained chromite; and significant nickel-copper sulphide mineralization and platinum group elements (Jackson and
Thayer 1972; Foose 1986; Loferski 1986). The chromite at Werner--Rex--Bug lakes does not exhibit
the nodular texture characteristic of podiform chromite ores in Alpine-type ophiolites (Duke 1983).
The author concurs with Scoates (1972) and with Blackburn and Vogg’s proposal (Blackburn et al.
1988) that the ultramafic-mafic rocks were part of a syn-tectonic stratiform intrusion that was deformed subsequent to its emplacement. The ultramafic-mafic intrusive rocks are tectonic fragments
from a dismembered layered sill or tabular body with a post-emplacement history that includes progressive compressional deformation; regional and local metamorphism; and multiple intrusions of
granitoid and pegmatoid felsic rocks. Mafic intrusive rocks associated with small ultramafic bodies in
high-grade metamorphic terranes, similar to the Werner--Rex--Bug lakes area, have been documented
and interpreted by other workers as remnants of tectonically disrupted stratiform complexes (Watkinson and Irvine 1964; Bowes et al. 1964; Papunen et al. 1979; Peltonen 1995; Peredery 1979; Girardi
and Ulbrich 1980; Loferski 1986). The Archean age and tectonic setting of the ultramafic-mafic rocks
at Werner--Rex--Bug lakes are similar to those of other layered intrusions (Jackson and Thayer 1972;
Duke 1983; Stowe 1995).
Granulite metamorphism, magmatism and anatexis of the English River Subprovince occurred
within a relatively short time period of less than 20 million years at pressures ranging from 0.3 to 0.6
GPa and temperatures of 500 to 7250C (Corfu et al. 1995). The anomalous, high thermal gradients
required for these events may have been achieved through a combination of crustal thickening due to
continuous north-south compression and possible magmatic underplating of the upper crust (Corfu et
al. 1995). Magmatic underplating requires a rising mantle plume that transports hot material to the
base of the crust resulting in rifting of the upper crust (Passchier et al. 1990). The mantle melts are
denser than the upper crust so that only a small portion of the melt intrudes the crust while the bulk of
the material remains at the crust-mantle interface (Passchier et al. 1990). The ultramafic-mafic magmas that accumulate below the upper crust provide the heat required for subsequent granulite metamorphism and anatexis.
Magmatic underplating provides a speculative explanation for the origin of the stratiform intrusion
at Werner--Rex--Bug lakes. Deposition of turbiditic sedimentary sequences of the English River Sub32
province occurred between 2720 and 2700 Ma (Corfu et al. 1995; Breaks 1991). Mantle melts were
emplaced in the sedimentary succession during magma underplating and rifting of the upper crust
sometime after 2700 Ma when the sediments were relatively horizontal. Once the magma was intruded it evolved, fractionated and cooled to form a horizontal, stratiform, sill-like intrusion. Olivineorthopyroxene-chromite cumulates were formed in the lowermost portion of the intrusion and gabbroanorthosite formed in the upper part of the intrusion. The emplacement of the sill was followed by:
1)
2)
3)
Intrusion of the Marijane batholith and Gone Lake pluton.
Compressional deformation culminating with the development of the Werner--Rex lakes
fault and the dominant east-striking regional fabric (D2) during high-grade metamorphism,
anatexis and intrusion of peraluminous granitoids and the granodiorite-granite suite (Breaks
1991).
Localized post-peak metamorphism activity including late deformation along the
Werner--Rex lakes fault and continued emplacement of the granodiorite-granite suite
(Breaks 1991).
The layered sill experienced tectonic reemplacement and internal imbrication during thrust faulting and folding. The deformation caused significant attenuation of the sill and removed some rock
units. Leucogabbro, gabbro and ultramafic xenoliths in the Marijane batholith and Gone Lake pluton
indicate that these plutons intruded the layered sill. The sill was initially altered and then metasomatized and metamorphosed during the emplacement of felsic intrusive rocks; high-grade metamorphism; and anatexis. The emplacement of the majority of intrusive rocks was followed by the development of the Werner--Rex lakes fault. Post-peak metamorphism deformation continued along the Werner--Rex lakes fault resulting in late strike-slip displacement; development of crossfaults; localized retrograde metamorphism; and continued deformation of supracrustal and intrusive rocks adjacent to the
fault.
RELATIONSHIP WITH THE BIRD RIVER SILL
The sill at Werner--Rex--Bug lakes shares many characteristics with the Bird River layered sill in Manitoba, located about 30 to 40 km due east of the Werner--Rex--Bug lakes area (Figure 4). The Bird River sill is
an Archean ultramafic-mafic stratiform tabular body consisting of ultramafic chromite cumulates, hornblende gabbro, anorthositic gabbro, anorthosite and porphyritic gabbro formed by the fractional crystallization of a single pulse of magma (Trueman 1971; Scoates 1983; Theyer 1991). The sill intrudes the Rice
Lake group, an assemblage of metavolcanic and metasedimentary rocks that include the Bird River greenstone belt and comprise the western extension of the English River Subprovince (see Figure 4; Trueman
1980). The sill intrudes metasedimentary and metavolcanic rocks and is intruded and metamorphosed by
the Maskwa batholith (Trueman 1971; Coats and Buchan 1979) which may be coeval with the Marijane
batholith (Trueman 1980).
The Bird River sill enjoyed a period of post-emplacement (Trueman 1971) compressional deformation and metamorphism similar in style to the deformation/metamorphism experienced by the
layered sill at Werner--Rex--Bug lakes. The effects of the deformation include east-striking faults parallel to igneous layering that attenuated the sill and removed some rock types; and north- and northwest-striking crossfaults that segmented, offset and “shuffled” sections of the sill (Trueman 1971;
Duke 1983). Metamorphism of the sill and surrounding country rocks consisted of two prograde
metamorphic events associated with D1 and D2 compressional deformation; and retrograde metamorphism related to late deformation along fault structures (Trueman 1980).
To summarise, the similarities between the Bird River sill and the sill at Werner--Rex--Bug lakes
are as follows:
1)
2)
3)
4)
Both sills are stratiform igneous intrusions comprised of similar rock types.
Both sills are interpreted to have evolved from a single pulse of magma (Trueman 1971;
Scoates 1972, 1983).
The post-emplacement deformational and metamorphic histories of the sills are associated
with a period of compressional deformation, metamorphism, magmatism and anatexis in
the English River Subprovince.
Chromite-bearing ultramafic rocks within both sills do not contain plagioclase and the
33
gabbros do not contain magnetite (Trueman 1971; Theyer 1991).
5) The sills host magmatic chromite and Ni-Cu sulphide mineralization (Trueman 1971).
6) The sills are on strike with each other (see Figure 4).
The similarities and spatial association suggest that the sills are coeval or segments of the same
intrusion.
GENESIS OF COBALT-COPPER SKARNOID DEPOSITS
Skarnoid cobalt and copper deposits at Werner and Loon’s Nest lakes occur in amphibolite to granulite
grade rocks at intrusive contacts. The skarnoid deposits are hosted by narrow, deformation zones that enclose a variety of mixed lithologies including lenses and layers of altered ultramafic-mafic rocks intermixed with metasedimentary migmatite and mafic gneiss. The presence of calcsilicate skarnoid is problematical since the metasedimentary migmatite assemblage does not include metasedimentary carbonate
rocks (Breaks 1991). Also, the skarnoid would have a more typical skarn-like mineral assemblage, dominated by pyroxene and garnet, if it had been derived from metasedimentary carbonate rocks. Therefore,
it’s unlikely that the skarnoid resulted from the metamorphism or metasomatism of a carbonate-rich metasedimentary protolith. Another possibility is that the skarnoid rocks are derived from serpentinized ultramafic rocks that were replaced during metasomatism. Serpentinized ultramafic rocks can be converted to
carbonate-bearing rocks with the addition of CO2 to a H2O-rich metasomatic hydrothermal fluid (Winkler
1976).
Several occurrences of metasomatic, carbonate-rich, replacement zones and skarns have been documented in ultramafic rocks such as: boudinaged ultramafic dikes in Zimbabwe (Nutt and Carr 1988);
Alpine-type ophiolites in Morocco (Leblanc and Billaud 1982); serpentinites adjacent to granitic intrusions in British Columbia (Warren and Thompson 1945); serpentinite pods in metasedimentary schists
in Finland (Papunen et al. 1979); ultramafic rocks of the Bird River sill (Coats and Buchan 1979); and
komatiitic flows in Australia (Mueller 1991; Mueller et al. 1991).
All of the examples listed above host cobalt arsenide mineralization, with the exception of komatiites in Australia and the Bird River sill, and demonstrate an association between cobalt and deformed
serpentinized and metasomatized ultramafic rocks. Serpentinized ultramafic rocks are generally considered to be the source for cobalt although the origin of the arsenic remains unresolved (Panayiotou
1980; Leblanc and Billaud 1982). It has been proposed (Leblanc and Billaud 1982; Panayiotou 1980)
that the arsenic was introduced during serpentinization of ultramafic rocks. It is possible that some of
the cobalt and arsenic at Werner Lake was derived from metasomatic fluids that leached and concentrated metals from the surrounding metasedimentary assemblage. Other metals present at Werner
Lake, such as nickel, copper, zinc, gold and silver may have been derived from a combination of
source rocks including the ultramafic rocks, metasediments and granitic intrusive rocks.
The calcsilicate rocks at Werner and Loon’s Nest lakes consist of calcite + forsterite (metamorphic
olivine) + magnetite + hercynite (iron spinel) + tremolite. Mueller (1991) and Mueller et al. (1991)
described very similar calcsilicate rocks (olivine + calcite + magnetite + hercynite + chlorite) in goldsilver skarns derived from sheared serpentinized komatiites at the Marvel Loch Mine in western Australia. The probable metamorphic conditions that existed during the formation of prograde olivinecarbonate skarn at Marvel Loch involved a maximum fluid temperature of 6400 + 200 C at a total
pressure of 4 + 1 kbar (Mueller et al. 1991). The metasomatic fluid was characterized by low CO2
content (ie: mole fraction CO2 < 0.2) (Mueller et al. 1991). These estimates are consistent with general pressure-temperature-fluid composition conditions required for skarn development (Einaudi et al.
1981).
It is speculated that metamorphic conditions similar to those at Marvel Loch may have existed
during the formation of the calcsilicate rocks at Werner and Loon’s Nest lakes because their stable,
high temperature, prograde mineral assemblages are essentially identical to the olivine-carbonate rocks
described (Mueller 1991; Mueller et al. 1991) at Marvel Loch. The calcsilicate rocks at Werner and
Loon’s Nest lakes could be high temperature equivalents of massive talc-carbonate zones hosted by
greenschist grade, metasomatized, ultramafic rocks in the Bird River sill at the Maskwa West Mine
(Coats and Buchan 1979). The talc-carbonate zones at the Maskwa West Mine are interpreted to have
formed during CO2 metasomatism of a serpentinized peridotite (Coats and Buchan 1979) situated in a
strong shear zone related to northwest-striking crossfaults.
34
Carbonate is not commonly found in exposures of ultramafic rocks in the Werner--Rex--Bug lakes
area, however, calcite in ultramafic rocks has been documented in underground exposures and in diamond-drill core at Gordon and Werner lakes (Scoates 1963, 1972; Assessment file 52L07NW E-2
(A-4, B-1)). Scoates (1972) also described calcite lenses in serpentine veins in ultramafic rocks at the
Gordon Lake Mine. The limited carbonate metasomatism of ultramafic rocks at Werner and Loon’s
Nest lakes indicates that the source of the CO2 was local and restricted. Calcsilicate rocks only occur
adjacent to the margins of granite-granodiorite intrusions suggesting that the intrusions may have been
a source for hydrothermal fluids during prograde thermal contact metamorphism. Metasomatic fluids
associated with migmatization and the intrusion of pegmatoid and granitoid leucosome may have also
been involved in the formation of the skarnoid. Carbon dioxide metasomatism probably occurred during an early stage in the metamorphic sequence with the ultramafic rocks in the stability field of serpentine. The ultramafic protolith was probably not chemically homogeneous due to possible primary
layering and previous serpentinization which may explain the layered appearance of some of the calcsilicate rocks.
The biotite-garnet schists are bimineralic marginal zones to the mineralized calcsilicate and amphibole rocks at the Werner Lake cobalt mine and Werner West zone. The schists are in contact with
metasedimentary migmatite along the north side of the mineralized zones. These schists may be metasomatized ultramafic-mafic rocks similar in composition and appearance to biotite + garnet metasomatic selvages that enclose ultramafic pods at Almo, Gordon, Werner and Rex lakes. The biotite-garnet schist may have formed during recrystallization of serpentinized ultramafic rock by a combination
of metasomatic and metamorphic reactions between the ultramafic rocks and the felsic country rocks.
Hydrous silicates such as amphibole, clinozoisite (iron-poor epidote) and clinochlore (magnesian
chlorite) overprint, alter and transect the earlier calcsilicate mineral assemblage and are coeval with
the deposition of late sulphide minerals. Amphibole occurs in thick foliation parallel layers or in
transecting veins and fractures. Metamorphic olivine, in the calcsilicate rocks at Werner Lake, was
strongly altered and replaced by antigorite during retrograde alteration. Serpentine is only stable at
very low mole fraction CO2, therefore, the occurrence of an abundant serpentine mineral (antigorite)
indicates that the metasomatic fluid responsible for retrograde alteration was CO2-poor (ie: mole fraction CO2 <0.01), with a low fluid temperature (<5000C) (Winkler 1976; Mueller et al. 1991). This
suggests that the metasomatic fluid evolved from a CO2-bearing fluid to a H2O-rich fluid as temperatures declined and the skarnoid cooled. The degree to which the early skarn assemblage is altered by
this late hydrosilicate stage is related to depth and proximity to a long-lived hydrothermal system (Einaudi et al. 1981). Deeply buried skarns show less alteration than hypabyssal skarns and distal skarns
show less alteration than proximal skarns (Einaudi et al 1981).
The skarnoid at Werner and Loon’s Nest lakes was developed during a period of high-grade metamorphism, anatexis and emplacement of granite-granodiorite intrusions. The stages of the skarnoid
development are listed below and summarized in Table 24 after Einaudi et al. (1981):
1)
2)
3)
Initial serpentinization and deformation of an ultramafic protolith. Possible development of
the marginal biotite-garnet metasomatic selvage during metamorphism and associated
emplacement of felsic intrusive rocks.
CO2 metasomatism of the serpentinized ultramafic protolith and initial mineralization
accompanying the crystallization and cooling of the magma and the evolution of the
mineralizing fluid. Metasomatic fluids infiltrated along foliation planes and fractures and
replaced the ultramafic rock with prograde mineral assemblages. Foliation parallel
pegmatoid/granitoid veins may have been emplaced at this time.
Retrograde alteration commenced and the deposition of sulphide minerals continued as
the hydrothermal system cooled down and became H2O-rich. Hydrous silicates, such as
amphibole, were deposited in layers and transecting fractures and veins. Prograde mineral
assemblages in the skarnoid at Loon’s Nest Lake are relatively well preserved with weak
retrograde alteration compared to the Werner Lake skarnoid. The lack of significant
alteration or mineralization at Loon’s Nest Lake suggests that: this skarnoid was more
deeply buried than the rocks at Werner Lake; or the hydrothermal system at Loon’s Nest
Lake was short-lived. Strong retrograde alteration of the skarnoid at Werner Lake consists
of alteration and replacement of forsterite (olivine) by antigorite and minor chondrodite; and
35
4)
the alteration of biotite, garnet and amphibole to chlorite-epidote (clinochlore and
clinozoisite). The chlorite-epidote alteration is characteristic of the late
hydrosilicate-sulphide stage in skarns (Einaudi et al. 1981).
Late deformation of the mineralized zones resulting in strongly to weakly foliated lithologies
and drag folding in the mineralized zones.
The development of skarnoid at Werner and Loon’s Nest lakes follows the general evolutionary
style of skarn development (see Table 24), which is the “major unifying feature” of skarns (Einaudi et
al. 1981).
Calcic iron skarns or iron-gold skarns are the only skarn-type known to contain significant cobalt
mineralization (Einaudi et al. 1981; Meinert 1984; Dawson 1996). These skarns are characterized by
iron-rich calcsilicate gangue (iron-rich garnet and pyroxene) with a minor amount of sulphide minerals
and retrograde actinolite-chlorite-epidote (Einaudi et al. 1981). Cobalt occurs as an arsenide (cobaltite) or in cobalt-rich pyrite (Smirnov 1979) and is concentrated in early formed sulphide minerals or
in later retrograde alteration assemblages (Dawson 1996). Cobalt content in iron-gold skarns is commonly low grade or anomalous and rarely exceeds 0.25% Co (Alexandrov 1962; Smirnov 1979; Einaudi et al. 1981; Meinert 1984; Robinson Jr. 1985). Higher grades of cobalt have been reported from
the Nickel Plate (0.49% Co) and Little Gem (6.25% Co) skarns in British Columbia (Warren and
Thompson 1945) and the Dashkesan skarns in Azerbaijan (Smirnov 1979). The skarnoids at Werner
and Loon’s Nest lakes have little in common with calcic magnetite skarns except that they host cobalt
mineralization. However, the cobalt values (up to 22% Co) at Werner Lake far exceed cobalt values
reported in calcic iron skarns.
The skarnoid mineral assemblages at Werner and Loon’s Nest lakes have more in common with
magnesian iron skarns. These skarns are characterized by prograde, magnesium-rich, mineral assemblages (calcite + forsterite + spinel + pyroxene) and retrograde assemblages that include serpentine,
magnetite and humite. However, sulphide mineralization consists of pyrrhotite, pyrite, chalcopyrite
and sphalerite and does not include cobaltite (Einaudi et al. 1981; Meinert 1992). In magnesian
skarns, the skarn minerals are magnesium-rich and do not contain much iron so that the available iron
in solution forms magnetite rather than iron silicate minerals (Meinert 1992). Therefore, the magnetite content in magnesian skarns is a function of the original magnesium-rich composition of the original host rocks (Einaudi et al. 1982). The relatively high magnetite content and dominance of magnesian silicate minerals in the skarnoids at Werner and Loon’s Nest Lake indicate that the original protolith was also magnesium-rich. The only magnesium-rich rocks in the study area are ultramafic rocks
which strongly suggests that the skarnoids evolved during the replacement of an ultramafic protolith.
To summarize, the cobalt-copper deposits at Werner and Loon’s Nest lakes are hosted by magnesian iron skarnoids (Einaudi et al. 1981; Mueller 1991; Mueller et al. 1991) that formed when invading metasomatic, hydrothermal fluids replaced a deformed and serpentinized ultramafic protolith. The
good to fair correlation between Au, Ag and Cu and the high Cu:Au ratios in the skarnoids are typical
geochemical characteristics of iron skarns (Ray and Webster 1995). The magnesium enrichment of
the skarnoid, and the abundant disseminated magnetite, is directly related to the high magnesium content of the original ultramafic protolith. Cobalt and copper sulphide mineralization may have been
derived from a combination of sources including the serpentinized ultramafic rocks and surrounding
metasedimentary rocks.
Skarn deposits are small and rare in the Superior Province, but a few examples of other Neoarchean skarns or skarnoids in northwestern Ontario have been documented by the author in the Red Lake
and Birch--Uchi greenstone belts (Atkinson et al.1990, 1991, 1992); in the Rainy Lake area near Fort
Frances (Parker et al. 1993); and at Muriel Lake in the Onaman--Tashota greenstone belt (Stott and
Parker 1997).
36
Recommendations for Mineral Exploration
All of the known mineral deposits in the Werner--Rex--Bug lakes area are relatively small and limited
in size. Magmatic nickel-copper sulphide and chromite mineralization is confined to a tectonically
disrupted, ultramafic-mafic stratiform intrusion that was tectonically dismembered into small lenses
and pods that have been aligned along regional faults and distributed throughout the strongly deformed and metamorphosed metasedimentary migmatite assemblage. Some magmatic sulphide mineralization has been remobilized and disseminated into gneissic country rocks and felsic intrusive
rocks during deformation, metasomatism and anatexis. The size and extent of known skarnoid cobalt
deposits are also confined to the limits of their ultramafic host rocks. The general geology of mineralized ultramafic-mafic intrusive rocks in the English River Subprovince is similar to Archean and Proterozoic nickel-copper sulphide-bearing ultramafic-mafic intrusive rocks in polydeformed metasedimentary migmatite assemblages in Finland (Papunen et al. 1979; Peltonen 1995).
The discovery of larger segments of disrupted ultramafic-mafic intrusions within the migmatite
assemblage is possible. Ultramafic-mafic bodies have been discovered in the metasediments up to 10
km north of the Werner--Rex lakes fault. Diamond drilling conducted by Anglo--Barrington Ltd. in
1959 (Assessment file 52L06NE C-1; DDH 59-4) intersected thick sections (up to 211 feet) of gabbro,
amphibolitized ultramafic rock and peridotite at Lake No.14 on the Manitoba--Ontario provincial border. Diamond drilling by Anglo--Barrington Ltd. also intersected wide sections of disseminated pyrrhotite, chalcopyrite, pyrite and magnetite in biotitic gneisses, talcose schists and gabbro at Swanny
Lake, north of Reynar Lake (Assessment file 52L06NE C-1). Numerous pods and lenses of “hornblendite, amphibolite and biotite-hornblende schists” have been mapped along other regional faults in
the area (Carlson 1958, Map 1957-2). Three pods are situated along a major east-southeast-striking
fault at Lake No.21 south of Narraway Lake; and 6 pods are distributed along a major northeast-striking fault that extends from Reynar Lake through Trapline Lake and beyond (Carlson 1958, Map
1957-2). These pods are located more than 8 km north of Gordon Lake. The presence of widely distributed ultramafic-mafic bodies suggests that other dismembered layered intrusions may occur within
the metasedimentary migmatite assemblage.
Regional surficial sediment sampling conducted by Morris (1996) has identified abundant concentrations of spinel, such as chromite (chrome-spinel), hercynite (iron-spinel) and gahnite (zincian
spinel), in heavy mineral separates from samples collected at Helder and Selwyn lakes, south of the
study area. Anomalous concentrations of chromite and/or hercynite may indicate the presence of
ultramafic pods since both spinels are common in ultramafic rocks and skarnoid deposits at Werner-Rex lakes. Gahnite (zincian spinel) is commonly associated with volcanogenic massive sulphide deposits in high-grade metamorphic terranes, such as: the copper-zinc deposits at Manitouwadge (James
et al. 1978; Zaleski et al. 1995); the lead-zinc deposits of Montauban-les-mines (Bernier et al. 1984);
and the Aggeneys copper-lead-zinc-silver deposits in South Africa (Spry 1987). Gahnite is also
known to occur in pegmatites and metamorphosed iron formations (F.W. Breaks, personal communication, 1997). Anomalous concentrations of spinel are also commonly associated with nickel, copper, zinc, lead and cobalt anomalies in humus and B and C horizon tills (Morris 1996) which may indicate the presence of other mineral deposits similar to those at Werner--Rex lakes. Copper and zinc
anomalies in B and C-horizon tills and some coincident anomalous concentrations of spinel were also
detected south of Werner Lake; in a large area east of Rex Lake; at Bug Lake; and in the Fortune lakes
area (Morris 1996).
A study of chrome spinels in glacial till, in the Vammala nickel belt in southwest Finland, indicated that potential nickel-copper sulphide-bearing ultramafic lithologies beneath glacial cover, may
be detected by examining the mineralogy of the heavy mineral fraction of till (Huhta and Peltonen
1994). The composition of spinels in till should be determined by electron microprobe and compared
to spinel compositions in known, exposed, nickel-copper sulphide-bearing ultramafic rocks to verify
the source lithology (Huhta and Peltonen 1994). The composition of the spinels must be used to discriminate between spinel associated with sulphide-bearing rocks and spinel associated with rocks that
are barren of sulphide mineralization. For example, gahnite associated with sulphide-bearing rocks is
typically zinc-rich, while gahnite in sulphide-free rocks is more iron-rich (Spry 1987; Spry and Scott
37
1986). Distinguishing the spinels is important since hercynite and gahnite spinel are also common
constituents of sulphide-free, high-grade metamorphosed pelitic rocks (Shulters and Bohlen 1987).
The fact that ultramafic-mafic bodies are widely distributed throughout the metasedimentary migmatite assemblage and aligned along several regional fault systems enhances the possibility of discovering more potentially economic nickel-copper and cobalt sulphide deposits in the English River Subprovince. Surficial sediment sampling combined with ground and airborne geophysical surveys, prospecting and detailed geological mapping may be effective in locating other ultramafic-mafic intrusive
rocks.
The occurrence of ultramafic-mafic pods and lenses has been documented in other parts of the English River Subprovince and in the Quetico Subprovince (Watkinson and Irvine 1964; MacTavish and
Dutka 1985, 1986, 1987; Breaks 1991; Williams 1989, 1991). These rocks are similar to the ultramafic-mafic rocks at Werner--Rex--Bug lakes and are distributed along major fault structures or occur as
isolated bodies in the metasedimentary assemblages. Their origins have generally remained enigmatic
although some workers have suggested that they represent mantle-derived diapiric protrusions or remnants of larger intrusions (Williams 1991; Watkinson and Irvine 1964). A revaluation of these rocks is
necessary to determine their origins and assess their economic potential.
38
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41
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43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
Table 25: cont’d. UTM co-- ordinates (Grid Zone 15; NAD 27) for all samples collected and analyzed from the Werner-Rex-Bug lakes study area. Northings and Eastings
obtained from digitized 1:50 000 EMR topograhic maps (52L/6 and 52L/7).
Appendix 1: Descriptions of Mineral Deposits and
Properties
91
ALMO–GORDON–WERNER–REX LAKES
1. Alcock-- Mosher A and A1 showings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
94
2. Alcock-- Mosher B, B1 and C showings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
96
3. Alcock-- Mosher D showing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
98
4. Central occurrence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
5. Dome No.1 occurrence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
6. Dome No.2 occurrence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
7. Dome No.3 occurrence (Werner Lake Nickel occurrence) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
8. Dome No.4 showing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
9. Duvan occurrence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
10. Eastern Mining and Smelting Corp. occurrence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
11. Falconbridge North occurrence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
111
12. Frederick No.1 occurrence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
13. Frederick No.2 occurrence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
14. Frederick No.3 occurrence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
15. Gordon Lake Mine (Rexora No.2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
16. Janet Lake occurrence (Contact Lake occurrence) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
17. KRL 33380/KRL 33381 occurrence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
18. Lower Fortune Lake occurrence (Stratmat occurrence) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
19. Norpax Oils and Mines Ltd. prospect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
20. Quebec Nickel Corporation Ltd. occurrence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
21. Quebec Nickel Corporation Ltd. - Beaverhouse Lake occurrence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132
22. Quebec Nickel Corporation Ltd. - Rex Lake occurrence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
23. Radioactive Minerals Ltd. - Rex Lake occurrence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135
24. Rexora No.3 occurrence (Vanderbrink showing) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
25. Rexora No.4 occurrence (Small Lake occurrence) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
26. Rexora No.5 prospect (Jeadle No.3 occurrence) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143
27. Sogemines No.1 occurrence (Shearn claim group, Norco claim group 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145
28. Sogemines No.2 occurrence (Sobeski claim group, Norco claim group 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
29. Werner Lake cobalt mine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149
30. Werner Lake cobalt - East zone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153
31. Werner Lake cobalt - West zone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156
32. Werner Lake - West Arm occurrence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160
Bug Lake
1. Bug Lake occurrence (North lakeshore showing) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164
2. North occurrence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166
3. Perkins occurrence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169
4. South occurrences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172
5. Steep Rock occurrences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175
92
Almo--Gordon--Werner--Rex lakes
93
1. DEPOSIT NAME: ALCOCK--MOSHER A AND A1 SHOWINGS
COMMODITIES: Ni, Cu, Cr, Pt, Pd
UTM COORDINATES: 357304.0 mE, 5592365.0 mN
UTM Datum: NAD27
MDI No.: MDI52L06NE00019
Mining Division: Kenora
Area Name: Reynar Lake
UTM ZONE: 15
Claim Map No.: G-2636
LOCATION AND ACCESS:
Almo Lake can be accessed from the Gordon Lake mine road. Launch a canoe on the narrow east-striking arm
of Almo Lake and paddle west along the south shore of the arm. Look for orange-brown gossan and large broken pieces of rock in a shallow, overgrown test pit on the south shore of the lake. The pit is at the water’s edge
but difficult to see from the lake. The occurrence can also be located by simply walking north for 100 to 150
m from the Gordon Lake mine road to the south shore of Almo Lake and walking along the shoreline until the
test pit is located.
EXPLORATION HISTORY:
1953: C. Alcock staked 60 claims at Almo (Tigar) Lake in July, 1953 after discovering and trenching 3 mineralized “peridotite” showings along the south shore of Almo Lake. Two grab samples taken by Mr. Alcock
from test pits at the A and A1 showings analyzed 1.56% Ni, 0.65% Cu and 1.17% Ni, 2.83% Cu. C. Alcock
and A. Mosher optioned the property to Selco Exploration Co. in August, 1953.
Selco sampled the property, conducted a ground magnetic geophysical survey and diamond drilled 2 holes totalling 424 feet on the A and A1 showings.
1954–1955: Norpax Oils and Mines Ltd. conducted ground magnetic geophysical surveys and diamond drilled
8 holes on the A and A1 showings. The holes intersected “mineralized peridotite” but analyses were not reported.
1970–1971: Consolidated Manitoba Mines Ltd. conducted ground magnetic and electromagnetic geophysical
surveys and geological mapping.
1975: Consolidated Canadian Faraday Ltd. conducted ground magnetic geophysical surveys over the A and
A1 showings and the north shore of Almo Lake.
1991: W. Hood and R. Knappett staked the property and completed geological mapping and ground magnetic
geophysical surveys.
GEOLOGICAL DESCRIPTION:
Province: Superior
Subprovince: English River
Metamorphism: 1) Type: Regional
2) Grade: Amphibolite
Assemblage: English River
The Alcock-- Mosher property is situated along the east-striking, vertical to north-dipping Werner-- Rex lakes
fault that extends along the contact between metasedimentary migmatite to the north and tonalitic rocks of the
Marijane batholith to the south. The fault strikes east across the Manitoba-- Ontario provincial boundary
through Reynar, Almo, Gordon, Werner and Rex lakes to Bug Lake and beyond for a strike length of about 32
km. The fault bifurcates into several fault splays at the east end of Werner Lake and the east end of Reynar
Lake. Overall horizontal displacement along the fault is interpreted to be dextral. Mineral lineations along the
south shore of Almo Lake have shallow plunges to the west-northwest.
Deformed, metamorphosed and metasomatized gabbro, leucogabbro, anorthosite and ultramafic pods are situated within and adjacent to the Werner-- Rex lakes fault. The ultramafic-mafic intrusive rocks may have originally been part of one stratiform, layered intrusion. The ultramafic pods are relatively small, amphibolitized
and recrystallized and host oxide and sulphide minerals such as magnetite, chromite, pyrrhotite and chalcopyrite. The Alcock-- Mosher A and A1 showings consist of 2 ultramafic pods located in the footwall of the Werner-- Rex lakes fault. The footwall consists of mylonitized tonalite-granodiorite of the Marijane batholith. The
hanging wall consists of diatexite containing garnet and cordierite porphyroblasts.
LITHOLOGIC DESCRIPTION:
The dominant lithologies at the Alcock-- Mosher showings consist of ultramafic rocks hosting variable amounts
of sulphide mineralization; tonalite-granodiorite; and metasedimentary migmatite.
The ultramafic rocks are dark green, massive, medium-grained, very hard and host disseminated magnetite,
pyrrhotite and chalcopyrite. In thin section the rocks have a recrystallized, granoblastic, polygonal texture and
94
are composed of pale green, weakly pleochroic amphibole (actinolite-tremolite); large patches of antigorite;
and dark green hercynite.
The tonalite-granodiorite is medium-grained, relatively equigranular, pink-grey with diffuse pegmatitic or pink
granitic patches. The tonalite is very strongly foliated with narrow (< 20 cm) mylonite zones and a common
gneissic texture with mafic platy minerals segregated into layers. The tonalite commonly hosts small xenoliths
of gabbro and ultramafic rock and late pegmatite dikes.
The migmatite is a massive, medium- to coarse-grained, homogeneous diatexite consisting of pink-white
weathering granitoid and pegmatoid material with less than 10% strongly foliated wacke and pelitic paleosome. The migmatite may contain 5-25% red-brown garnet porphyroblasts and 0-5% cordierite porphyroblasts.
MINERAL DESCRIPTION:
Sulphide minerals consist of chalcopyrite, pyrrhotite and possible violarite. Disseminated magnetite and hercynite were also observed.
Sulphide and oxide minerals are disseminated throughout the ultramafic rocks. Sulphide minerals also occur
along 2 mm wide fractures with pale green actinolite-tremolite alteration halos. The combined sulphide mineral content is about 5%. In thin section the sulphide minerals are disseminated around silicate mineral grain
boundaries and concentrated along hairline fractures. Selco geologists identified violarite at this occurrence.
Diamond drilling, conducted by Selco, intersected a fault zone and 3-5% combined chalcopyrite-pyrrhotite in
serpentinized talc-chlorite-biotite schist; serpentinized ultramafic rock; and hornblende-biotite gneiss with
variable amounts of garnet. The best mineralized drill-hole sections analyzed 0.21% Ni and 0.39% Cu across
6 feet in DDH No. 1 (Showing A) and 0.15% Ni and 0.03% Cu across 5 feet in DDH No. 2 (Showing A1).
Two chip samples taken by Selco analyzed 0.90% Ni and 0.58% Cu across 5 feet and 0.51% Ni and 0.33% Cu
across 5 feet while 3 grab samples analyzed 1.03% Ni, 0.25% Cu; 1.32% Ni, 0.44% Cu and 0.21% Ni, 0.21%
Cu (grab sample across 15 feet). Selco diamond drilled 2 holes (DDH No.7 and No. 8) 600 and 800 feet west
of the A showing to test 2 strong magnetic anomalies. The holes intersected the fault zone but failed to intersect mineralized peridotite or any magnetic rock that would explain the presence of the anomalies.
ALTERATION DESCRIPTION:
The primary mineralogy of the ultramafic rocks has been replaced by a prograde metamorphic mineral assemblage of actinolite-tremolite and hercynite with retrograde alteration of amphibole to antigorite.
MINERALIZED ZONE:
Name: A showing Length: 12.2 m Thickness: 3.65 m Strike: 2700 Dip: 800 Plunge: west-northwestShape: Cylinder Structure: Fault Character: Podiform
Classification: Magmatic
ASSESSMENT FILES (Kenora Resident Geologist office):
52L06NE B-1, F-1, K-2, N-1 and U-1.
ASSAYS:
Sample
No.
Rock
Name
Au
(ppb)
Ag
(ppm)
Pd
(ppb)
Pt
(ppb)
Cr
(ppm)
Co
(ppm)
Ni
(ppm)
Cu
(ppm)
Zn
(ppm)
94JRP1076
u/m rock
15
3
519
118
3128
143.7
0.40%
2892
71.15
94JRP1078
u/m rock
6
3
366
143
2602
118.9
2565
1069
61.78
u/m – ultramafic rock
A grab sample, collected from the peridotite at the A showing, by Blackburn and Vogg (Blackburn et al. 1988)
analyzed 100 ppb Pt and 760 ppb Pd. Sample 94JRP1078 analyzed 0.32% Cr2O3 and sample 94JRP1079 analyzed 0.44% Cr2O3.
95
2. DEPOSIT NAME: ALCOCK--MOSHER B, B1 AND C SHOWINGS
COMMODITIES: Ni, Cu, Pd, Pt
UTM COORDINATES: 355673.0 mE, 5592469.0 mN
UTM Datum: NAD27
MDI No.: MDI52L06NE00020
Mining Division: Kenora
Area Name: Reynar Lake
UTM ZONE: 15
Claim Map No.: G-2636
LOCATION AND ACCESS:
Almo Lake can be accessed from the Gordon Lake mine road. Launch a canoe on the narrow east-striking arm
of Almo Lake and paddle west to the extreme west shore of the arm. Leave the canoe on the shore and walk
due west about 180 to 200 m along the narrow, linear gully between the steep outcrop ridges. The trenches are
situated along the base of the steep outcrops on either side of the gully. Unfortunately, very little can be seen
since the trenches are full of water, moss and debris and overgrown with vegetation.
EXPLORATION HISTORY:
1953: C. Alcock staked 60 claims at Almo (Tigar) Lake in July, 1953 after discovering and trenching 3 mineralized “peridotite” showings along the south shore of Almo Lake. A grab sample taken by Mr. Alcock from
the B and C showings analyzed 0.58% Ni. C. Alcock and A. Mosher subsequently optioned the property to
Selco Exploration Co. in August, 1953.
Selco sunk 8 trenches in overburden across the narrow gully, conducted a ground magnetic survey and diamond drilled 3 holes totalling 576 feet. The holes intersected biotite-talc-chlorite schist and variably mineralized “peridotite”.
1954-- 1955: Norpax Oils and Mines Ltd. conducted ground magnetic geophysical surveys and diamond drilled
14 holes totalling 3672 feet. The holes intersected “mineralized peridotite” but analyses were not reported.
Results were reported for DDH No. 1 and 2 in The Northern Miner the best result being 0.83% Ni and 0.48%
Cu across 12.5 feet.
1962: Norpax Oils and Mines Ltd. conducted ground magnetic and electromagnetic geophysical surveys.
1970-- 1971: Consolidated Manitoba Mines Ltd. conducted ground magnetic and electromagnetic geophysical
surveys and geological mapping.
1975: Consolidated Canadian Faraday Ltd. conducted ground magnetic geophysical surveys over the B and C
showings.
1991: W. Hood and R. Knappett staked the property and completed geological mapping and ground magnetic
geophysical surveys.
GEOLOGICAL DESCRIPTION:
Province: Superior
Subprovince: English River
Metamorphism: 1) Type: Regional
2) Grade: Amphibolite
Assemblage: English River
The Alcock-- Mosher property is situated along the east-striking, vertical to north-dipping Werner-- Rex lakes
fault that extends along the contact between metasedimentary migmatite to the north and tonalitic rocks of the
Marijane batholith to the south. The fault strikes east across the Manitoba-- Ontario provincial boundary
through Reynar, Almo, Gordon, Werner and Rex lakes to Bug Lake and beyond for a strike length of about 32
km. The fault bifurcates into several fault splays at the east end of Werner Lake and the east end of Reynar
Lake. Overall horizontal displacement along the fault is interpreted to be dextral.
Deformed, metamorphosed and metasomatized gabbro, leucogabbro, anorthosite and ultramafic pods are situated within and adjacent to the Werner-- Rex lakes fault. The ultramafic-mafic intrusive rocks may have originally been part of one stratiform, layered intrusion. The ultramafic pods are relatively small, amphibolitized
and recrystallized and host oxide and sulphide minerals such as magnetite, chromite, pyrrhotite and chalcopyrite. The Alcock-- Mosher B, B1and C showings consist of several small ultramafic pods located in the footwall of the Werner-- Rex lakes fault. The footwall consists of mylonitized tonalite-granodiorite of the Marijane
batholith intruded by late pegmatite dikes. The hanging wall consists of diatexite with numerous tectonic inclusions and lenses of amphibolitized gabbro.
LITHOLOGIC DESCRIPTION:
The dominant lithologies at the Alcock-- Mosher showings consist of ultramafic rocks hosting variable amounts
of sulphide mineralization; gabbro; tonalite-granodiorite; and metasedimentary migmatite.
96
Ultramafic rocks are not exposed at this occurrence. Reports from assessment files describe the rock as mineralized peridotite pods that pinch and swell along a strike length of about 300 m. Diamond drilling intersected altered ultramafic rock on both sides of the fault.
The gabbro occurs along the south side of the gully on the footwall side of the fault. The gabbro is dark greygreen, medium-grained, amphibolitized, recrystallized and strongly foliated. Feldspar porphyritic gabbro containing 40 to 60% white plagioclase phenocrysts up to 5 cm x 3 cm in size is situated in close proximity to the
trenches. The feldspar phenocrysts are moderately flattened in strongly foliated gabbro.
The tonalite-granodiorite is medium-grained, relatively equigranular, pink-grey with diffuse pegmatitic or pink
granitic patches. The tonalite is very strongly foliated with narrow (< 20 cm) mylonite zones and a common
gneissic texture with mafic platy minerals segregated into layers. The tonalite commonly hosts small xenoliths
of gabbro and ultramafic rock and late pegmatite dikes.
The migmatite is a massive, medium- to coarse-grained, inhomogeneous diatexitic metasedimentary migmatite
consisting of pink-white weathering granitoid and pegmatoid material with 10 to 40 % strongly foliated wacke
and pelitic paleosome. The migmatite may contain tectonic inclusions and lenses of amphibolitized gabbro.
MINERAL DESCRIPTION:
Mineralization is not exposed at the occurrence. Geological reports in assessment files indicate that the majority of peridotite intersected in diamond drilling, and exposed in trenches, was weakly mineralized with up to
10% pyrrhotite and minor chalcopyrite. Selco reported about 3% disseminated pyrrhotite in the foliated tonalite on the footwall side of the trenches.
The following analyses were reported from Selco’s diamond drilling and trench sampling: DDH No. 4 (Showing B) intersected 0.21% Ni, 0.14% Cu across 10 feet; DDH No.5 (Showing C) intersected 0.64% Ni, 0.33%
Cu across 31.5 feet; and DDH No. 6 (Showing B1) intersected 0.59% Ni, 0.21% Cu across 8.3 feet. Two channel samples collected at Showing C analyzed: 0.2% Ni and 0.81% Cu across 2 feet; and 0.72% Ni and 0.62%
Cu across 6 feet. A grab sample taken from Showing C analyzed 0.51% Ni and 0.14% Cu. A 20-foot chip
sample taken at Showing B1 analyzed 0.18% Ni, 0.16% Cu, 0.02 opt Pt and 0.02 opt Pd. Trenches at Showing
C exposed a complete bedrock section across the fault zone while the other trenches exposed weakly mineralized peridotite float and partial bedrock sections.
ALTERATION DESCRIPTION:
Information on the alteration was obtained from diamond-drill logs and geological reports in assessment files.
Diamond drilling intersected ultramafic pods with thick outer margins of biotite-chlorite-talc schist and serpentinized “peridotite” enclosing a less altered peridotite core.
MINERALIZED ZONE:
Name: B, B1 and C showings Length: 304.0 m Thickness: 11.58 m Strike: 2700 Dip: 800
Plunge: west-northwest Shape: Cylinder Structure: Fault Character: Podiform
Classification: Magmatic
ASSESSMENT FILES (Kenora Resident Geologist office):
52L06NE B-1, F-1, K-2, N-1 and U-1.
ASSAYS:
No samples taken at this location due to poor exposure.
97
3. DEPOSIT NAME: ALCOCK--MOSHER D SHOWING
COMMODITIES: Ni, Cu, Cr, Pd, Pt
UTM COORDINATES: 355163.0 mE, 5592418.0 mN
UTM Datum: NAD27
MDI No.: MDI52L06NE00021
Mining Division: Kenora
Area Name: Reynar Lake
UTM ZONE: 15
Claim Map No.: G-2636
LOCATION AND ACCESS:
Almo Lake can be accessed from the Gordon Lake mine road. Launch a canoe on the narrow east-striking arm
of Almo Lake and paddle west to the extreme west shore of the arm. Leave the canoe on the shore and walk
due west about 580 m along the narrow, linear gully between the steep outcrop ridges. A test pit is situated
under blown down trees on top of a steep outcrop on the south side of the gully. The pit is also 30 to 50 m
from the shore of a small unnamed lake immediately west of Almo Lake. Unfortunately, very little can be
seen in the test pit. A small outcrop exposure of the ultramafic pod is situated beside the pit.
EXPLORATION HISTORY:
1953: C. Alcock staked 60 claims at Almo (Tigar) Lake in July, 1953 after discovering and trenching 3 mineralized “peridotite” showings along the south shore of Almo Lake. A grab sample taken by Mr. Alcock from
the D showing, analyzed 1.04% Ni and 1.16% Cu. C. Alcock and A. Mosher subsequently optioned the property to Selco Exploration Co. in August, 1953. Selco sampled the property and conducted a ground magnetic
geophysical survey.
1954-- 1955: Norpax Oils and Mines Ltd. conducted ground magnetic geophysical surveys and diamond drilled
19 holes. The holes intersected “mineralized peridotite” but analyses were not reported.
1962: Norpax Oils and Mines Ltd. conducted ground magnetic and electromagnetic geophysical surveys.
1970-- 1971: Consolidated Manitoba Mines Ltd. conducted ground magnetic and electromagnetic geophysical
surveys and geological mapping.
1975: Consolidated Canadian Faraday Ltd. conducted ground magnetic geophysical surveys over the B and C
showings.
1991: W. Hood and R. Knappett staked the property, completed geological mapping and ground magnetic geophysical surveys.
GEOLOGICAL DESCRIPTION:
Province: Superior
Subprovince: English River
Metamorphism: 1) Type: Regional
2) Grade: Amphibolite
Assemblage: English River
The Alcock-- Mosher property is situated along the east-striking, vertical to north-dipping Werner-- Rex lakes
fault that extends along the contact between metasedimentary migmatite to the north and tonalitic rocks of the
Marijane batholith to the south. The fault strikes east across the Manitoba-- Ontario provincial boundary
through Reynar, Almo, Gordon, Werner and Rex lakes to Bug Lake and beyond for a strike length of about 32
km. The fault bifurcates into several fault splays at the east end of Werner Lake and the east end of Reynar
Lake. Overall horizontal displacement along the fault is interpreted to be dextral. S-drag folds with shallow
plunges to the west were observed immediately north of the fault.
Deformed, metamorphosed and metasomatized gabbro, leucogabbro, anorthosite and ultramafic pods are situated within and adjacent to the Werner-- Rex lakes fault. The ultramafic-mafic intrusive rocks may have originally been part of one stratiform, layered intrusion. The ultramafic pods are relatively small, amphibolitized
and recrystallized and host oxide and sulphide minerals such as magnetite, chromite, pyrrhotite and chalcopyrite. The Alcock-- Mosher D showing consists of a small ultramafic pod located in the footwall of the Werner-Rex lakes fault. The footwall consists of mylonitized tonalite-granodiorite of the Marijane batholith intruded
by late pegmatite dikes. The hanging wall consists of diatexite with numerous tectonic inclusions and lenses
of amphibolitized gabbro.
LITHOLOGIC DESCRIPTION:
The dominant lithologies at the Alcock-- Mosher showings consist of ultramafic rocks hosting variable amounts
of sulphide mineralization; gabbro; tonalite-granodiorite; and metasedimentary migmatite.
The ultramafic rocks are coarse-grained and dark green with large angular and amoeboid aggregates of magnetite up to 9 cm x 5 cm in size and large disseminated magnetite crystals with octahedron shapes. In thin sec98
tion the rock is recrystallized with a granoblastic, polygonal texture and consists of pale green, weakly pleochroic amphibole (actinolite-tremolite) and large patches of very fine-grained antigorite.
The gabbro occurs along the south side of the gully on the footwall side of the fault. The gabbro is dark greygreen, medium-grained, amphibolitized, recrystallized and strongly foliated. Feldspar porphyritic gabbro containing 40 to 60% white plagioclase phenocrysts up to 5 cm x 3 cm in size is situated in close proximity to the
trenches. The feldspar phenocrysts are moderately flattened in strongly foliated gabbro.
The tonalite-granodiorite is medium-grained, relatively equigranular, pink-grey with diffuse pegmatitic or pink
granitic patches. The tonalite is very strongly foliated with narrow (< 20 cm) mylonite zones and a common
gneissic texture with mafic platy minerals segregated into layers. The tonalite commonly hosts small xenoliths
of gabbro and ultramafic rock and late pegmatite dikes.
The migmatite is a massive, medium- to coarse-grained, inhomogeneous diatexitic metasedimentary migmatite
consisting of pink-white weathering granitoid and pegmatoid material with 10 to 40 % strongly foliated wacke
and pelitic paleosome. The migmatite may contain inclusions and lenses of amphibolitized gabbro.
MINERAL DESCRIPTION:
Sulphide minerals consist of pyrrhotite and chalcopyrite. Magnetite and chromite were also observed.
Ultramafic rocks host up to 10% disseminated pyrrhotite and 3% disseminated chalcopyrite. Magnetite and
chromite occur in large irregular aggregates and individual disseminated crystals. In thin section the sulphide
minerals are disseminated around silicate mineral grain boundaries and concentrated along hairline fractures or
in irregular aggregates.
Three chip samples taken by Selco at the occurrence analyzed as follows: 0.28% Ni and 0.04% Cu across 5
feet; 0.31% Ni and 0.08% Cu across 2 feet; and 0.24% Ni and 0.11% Cu across 3 feet. A grab sample analyzed 0.28% Ni and nil Cu.
ALTERATION DESCRIPTION:
The primary mineralogy of the ultramafic rocks has been replaced by a prograde metamorphic mineral assemblage of actinolite-tremolite with retrograde alteration of amphibole to antigorite.
MINERALIZED ZONE:
Name: D showing Length: 15.24 m Thickness: 9.14 m Strike: 2700 Dip: 800 Plunge: west-northwest
Shape: Cylinder Structure: Fault Character: Podiform
Classification: Magmatic
ASSESSMENT FILES (Kenora Resident Geologist office):
52L06NE B-1, F-1, K-2, N-1 and U-1.
ASSAYS:
Sample No.
Rock
Name
Au
(ppb)
Ag
(ppm)
Pd
(ppb)
Pt
(ppb)
Cr
(ppm)
Co
(ppm)
Ni
(ppm)
Cu
(ppm)
Zn
(ppm)
94JRP1085
u/m rock
<3
2
308
103
2.7%
240.3
2509
898
126.9
94JRP1086
u/m rock
31
4
1145
249
5457
378.1
0.39%
2552
36.17
94JRP1087
u/m rock
6
5
399
87
14900
325.4
2875
2114
79.63
94JRP1088
gabbro
<3
4
<5
<10
220
54.62
47
184
53.99
u/m - ultramafic
Sample 94JRP1086 also analyzed 0.85% Cr2O3.
99
4. DEPOSIT NAME: CENTRAL OCCURRENCE
COMMODITIES: Ni, Cu, Cr
UTM COORDINATES: 364129.0 mE, 5591628.0 mN
UTM Datum: NAD27
MDI No.: MDI52L07NW00038
Mining Division: Kenora
Area Name: Werner Lake
UTM ZONE: 15
Claim Map No.: G-2654
Mining Location: KRL 30055
LOCATION AND ACCESS:
The Central occurrence is located about 400 m southeast of Gordon Lake and is accessible from the Gordon
Lake mine road. There are no trenches or surface workings at this location.
EXPLORATION HISTORY:
1942: A. Vanderbrink and H. Byberg made several copper-nickel discoveries in and around the Gordon-- Werner lakes area. Noranda Mines Ltd. conducted ground geophysical surveys, stripping, trenching and diamond
drilling on these properties.
1948 - 1949: The area was restaked by Aero Prospecting Syndicate and acquired by Rexora Mining Corporation Ltd. who conducted some diamond drilling. The property was optioned to Falconbridge Nickel Mines
Ltd. who conducted magnetic and electromagnetic ground geophysical surveys and over 10 000 feet of diamond drilling in 1949.
1952: The property was diamond drilled by Quebec Nickel Corporation Ltd.
1971: Consolidated Canadian Faraday Ltd. conducted ground geophysical surveys.
GEOLOGICAL DESCRIPTION:
Province: Superior
Subprovince: English River
Metamorphism: 1) Type: Regional
2) Grade: Amphibolite
Assemblage: English River
The Central occurrence is situated on the Werner-- Rex lakes fault that extends along the contact between a
metasedimentary migmatite assemblage to the north and the tonalitic Marijane batholith. The fault strikes east
across the Manitoba-- Ontario provincial border through Reynar, Almo, Gordon, Werner and Rex lakes to Bug
Lake and beyond for a strike length of approximately 32 km. The fault strikes southeast and dips north in the
vicinity of the Central occurrence.
Deformed, metamorphosed and metasomatized gabbro, porphyritic gabbro and ultramafic pods are situated
within and adjacent to the Werner-- Rex lakes fault and may have originally been part of one stratiform, layered
intrusion. The ultramafic pods are relatively small, amphibolitized and recrystallized and host oxide and sulphide minerals such as magnetite, chromite, pyrrhotite and chalcopyrite.
LITHOLOGIC DESCRIPTION:
Pink to white weathering diatexite, granitic pegmatite dikes and strongly foliated tonalitic rocks of the Marijane batholith are the dominant lithologies in the vicinity of the Central occurrence. Discontinuous lenses and
pods of fine- to coarse-grained mafic gneiss, biotite-garnet schist and gabbro are also common. The mafic
gneiss contains up to 10% garnet porphyroblasts. A strong foliation strikes 2800 and dips moderately to the
northeast. Abundant Z-drag folding was also observed in all rock types. Sulphide mineralization is hosted by
ultramafic rocks.
MINERAL DESCRIPTION:
Little information is available on this occurrence. An outcrop of “peridotite” was exposed at the occurrence
and was reported to be well mineralized across a width of 25 feet. Samples collected from the peridotite by
Rexora Mining Corporation Ltd. analyzed 1.4% Ni and 0.60% Cu. Three diamond-drill holes completed by
Falconbridge Nickel Mines Ltd. intersected the following mineralized sections: 0.45% Ni across 87 feet;
0.46% Cu and 0.53% Ni across 19.1 feet; and 0.54% Cu and 0.71% Ni across 29 feet. A “substantial amount
of chrome” was also noted in diamond-drill core.
ASSESSMENT FILES (Kenora Resident Geologist office):
52L07NW E-2 (A-1, B-1), N-2, O-1.
100
5. DEPOSIT NAME: DOME No. 1 OCCURRENCE
COMMODITIES: Cu
UTM COORDINATES: 369360.0 mE, 5590850.0 mN
UTM Datum: NAD27
MDI No.: MDI52L07NW00045
Mining Division: Kenora
Area Name: Werner Lake
UTM ZONE: 15
Claim Map No.: G-2654
Mining Location: KRL 19123
LOCATION AND ACCESS:
The occurrence is located on the north shore of Loon’s Nest Lake and is accessible by floatplane or by walking
south from Upper Falls Lake. Only 1 trench was found although 4 trenches were reported to have been sunk
on the property. The trench is 4.5 m long, 1.5 m wide and 2.5 m deep and is located on the north side of a
steep, narrow outcrop.
EXPLORATION HISTORY:
1942-- 1945: Dome Exploration Canada Ltd. conducted prospecting, trenching, sampling and ground geophysical surveys over a large claim group of 60 contiguous mining claims. One diamond-drill hole (DDH No.26)
was completed on the No. 1 occurrence but no mineralization was intersected in the drill core. A channel sample taken across the mineralized zone analyzed 2.75% Cu across 1.5 feet.
GEOLOGICAL DESCRIPTION:
Province: Superior
Subprovince: English River
Metamorphism: 1) Type: Regional
2) Grade: Granulite
Assemblage: English River
The copper sulphide mineralization at Loon’s Nest Lake is hosted within a narrow, linear, discontinuous, eaststriking zone composed of the same lithologies found in the Werner Lake cobalt-copper zone. The Loon’s Nest
Lake zone extends along the north shore of Loon’s Nest Lake and consists of a strongly deformed assemblage
of granulite grade biotite-garnet schist interlayered with small ultramafic-mafic pods and skarnoid rocks. The
zone is located 100 m north of the fault-bounded contact of the Marijane batholith. The zone is situated between massive homogeneous diatexite to the north and metatexitic metasedimentary migmatite to the south.
The metatexite contains up to 30% porphyroblastic garnet and is interlayered with orthopyroxene-bearing mafic gneiss. The metatexite is intruded by thick, massive, pink weathering, granodioritic dikes with potassium
feldspar phenocrysts and gabbro xenoliths.
The Dome No.1 is a 1 to 2 m wide unit of coarse biotite-garnet schist containing 25 to 40% garnet porphyroblasts and 15% disseminated magnetite. The schist is interlayered with a fine-grained, dark green ultramafic
rock with minor garnet and quartz.
LITHOLOGIC DESCRIPTION:
Biotite-garnet schist: A 1 to 2 m wide unit of medium- to coarse-grained, biotite-garnet schist containing 25 to
40% garnet porphyroblasts, coarse biotite and 15% disseminated magnetite enclosed within metasedimentary
migmatite and white-pink weathering peraluminous leucosome.
Ultramafic rock: A fine-grained, dark green, recrystallized amphibole-rich ultramafic rock containing some
minor garnet porphyroblasts.
Migmatite: Metatexite with 40 to 90% moderately to strongly foliated wacke and pelitic paleosome is interlayered with medium- to coarse-grained granitoid and pegmatoid leucosome. Commonly intruded by late-tectonic pegmatitic granitic dikes.
MINERAL DESCRIPTION:
Mineralization at the Dome No.1 occurrence consists of a seam or vein of 3 to 5% combined chalcopyrite and
pyrite in biotite-garnet schist. Disseminated chalcopyrite also occurs in fine-grained ultramafic rock and replaces and overgrows silicate minerals. Individual grains of chalcopyrite are rimmed by chlorite and chalcopyrite is disseminated along narrow chlorite veinlets that transect prograde silicate minerals. Pegmatite dikes
also host disseminated pyrite and chalcopyrite. Minor native copper was observed on a few fracture surfaces.
ALTERATION DESCRIPTION:
Minor chloritization associated with the sulphide mineralization.
MINERALIZED ZONE:
Name: No.1 zone Thickness: 1.5 m Length: n/a Strike: 2630 Dip: 900 Shape: Irregular
Structure: Shear zone Character: Disseminated, vein
101
Classification: Remobilized, hydrothermal
ASSESSMENT FILES (Kenora Resident Geologist office):
52L07NW D-3.
ASSAYS:
Sample No.
Rock Name
Au
(ppb)
Ag
(ppm)
Pd
(ppb)
Pt
(ppb)
Cr
(ppm)
Co
(ppm)
Ni
(ppm)
Cu
(ppm)
Zn
(ppm)
94JRP1145
ultramafic
34
<2
<5
< 10
62
53.8
64
2315
84.7
94JRP1146
bt-grt schist
5
2
<5
< 10
219
90.4
< 40
1117
119
bt - biotite; grt - garnet
102
6. DEPOSIT NAME: DOME No. 2 OCCURRENCE
COMMODITIES: Cu
UTM COORDINATES: 370159.0 mE, 5590826.0 mN
UTM Datum: NAD27
MDI No.: MDI52L07NW00046
Mining Division: Kenora
Area Name: Werner Lake
and 19124
UTM ZONE: 15
Claim Map No.: G-2654
Mining Location: KRL 19120
LOCATION AND ACCESS:
The occurrence is located on the north shore of Loon’s Nest Lake and is accessible by floatplane or by walking
south from Upper Falls Lake. It is located on a small peninsula near the mouth of the creek that flows out of
Beaverhouse Lake. One trench, 4.5 m long and 1.5 m wide, is located on the north side of the outcrop.
EXPLORATION HISTORY:
1942-- 1945: Dome Exploration Canada Ltd. conducted prospecting, trenching, sampling and ground geophysical surveys over a large claim group of 60 contiguous mining claims. Six short diamond-drill holes were targeted on the No. 2 occurrence.
GEOLOGICAL DESCRIPTION:
Province: Superior
Subprovince: English River
Metamorphism: 1) Type: Regional
2) Grade: Granulite
Assemblage: English River
Copper sulphide mineralization at Loon’s Nest Lake is hosted within a narrow, linear, discontinuous, east-striking zone composed of the same lithologies found in the Werner Lake cobalt-- copper zone. The Loon’s Nest
Lake zone extends along the north shore of Loon’s Nest Lake and consists of a strongly deformed assemblage
of granulite grade biotite-garnet schist interlayered with small ultramafic-mafic pods and skarnoid rocks. The
zone is located 100 m north of the fault-bounded contact of the Marijane batholith. The zone is situated between massive homogeneous diatexite to the north and metatexitic metasedimentary migmatite to the south.
The metatexite contains up to 30% porphyroblastic garnet and is interlayered with orthopyroxene-bearing mafic gneiss. The metatexite is intruded by thick, massive, pink weathering, granodioritic dikes with potassium
feldspar phenocrysts and gabbro xenoliths.
The Dome No.2 occurrence consists of skarnoid rocks that are almost identical to the rocks at the Werner Lake
cobalt mine and West cobalt zone. The skarnoid occurs at an intrusive contact with a thick granodioritic, potassium feldspar megacrystic dike in the footwall of the occurrence.
LITHOLOGIC DESCRIPTION:
Calcsilicate rock at the Dome No.2 occurrence is pale grey, massive, medium-grained and dominantly composed of white-grey calcite. Broken rock pieces at the occurrence contain coarse calcite crystals that are several centimetres in size. The calcsilicate unit is lens- or pod-shaped and about 2 m wide. The rock contains a
prograde mineral assemblage calcite + forsterite + hercynite-spinel + tremolite + magnetite (5-30%) that is
weakly retrograded to antigorite. In thin section, the rock is granoblastic with large polygonal grains of calcite; minor fibrous patches of antigorite along rims and fractures in olivine and tremolite; disseminated anhedral magnetite grains intergrown and interstitial with calcite and olivine; large subhedral green grains of hercynite intergrown with calcite and containing magnetite lamellae and magnetite on rims and fractures; and aggregates and individual acicular crystals of tremolite. The calcsilicate rock is transected by 1 to 3 cm wide actinolite-tremolite veins.
The calcsilicate rock is interlayered with a massive, dark green-black, fine- to medium-grained ultramafic rock
that consists of magnesian hastingsite, tremolite, disseminated magnetite, quartz and small lenses of black
magnesian hornblende. This rock is moderately to strongly altered with large irregular patches of pale green,
fine-grained, disseminated clinozoisite and clinochlore.
The calcsilicate rock at Loon’s Nest Lake represents a skarn-like, high temperature, prograde mineral assemblage overprinted by layers and veins of hydrous silicates such as amphibole.
MINERAL DESCRIPTION:
Mineralization at the Dome No.2 occurrence consists of about 1 to 5% combined, fine-grained, disseminated
chalcopyrite and pyrite hosted in calcsilicate rocks. Chalcopyrite replaces magnetite and amphibole and occurs along fractures in olivine and amphibole. Chalcopyrite is also interstitial to large amphibole crystals.
103
Magnetite appears to have been the last oxide mineral to form in the calcsilicate rock. The magnetite is intergrown and interstitial with prograde silicate and carbonate minerals but also overgrows and replaces earlier
formed hercynite-spinel. The ultramafic rocks contain large, thick aggregates or patches of coarse chalcopyrite
(up to 35%) as well as disseminated chalcopyrite. These observations indicate that chalcopyrite was deposited
after the prograde mineral assemblage had formed.
Diamond drilling by Dome Exploration at the Dome No.2 occurrence intersected 1.85%Cu across 4.5 feet in
DDH No.9; 4.13% Cu across 3.5 feet in DDH No.10; and 2.09% Cu across 9 feet in DDH No.11 (Assessment
file 52L07NW D-3).
ALTERATION DESCRIPTION:
The protolith for the replacement skarnoid at the Dome No. 2 occurrence was probably a serpentinized ultramafic rock. Metasomatism and replacement of the ultramafic protolith accompanied the emplacement and
crystallization of the syn- to late-tectonic granite-granodiorite intrusion adjacent to the deposit. The skarnoid
consists of prograde mineral assemblages that constitute the 2 main rock types at the occurrence: amphibolerich rocks (magnesian hastingsite-magnesian hornblende-tremolite) and the calcsilicate rock (calcite-forsteritetremolite-hercynite-magnetite). Weak retrograde alteration accompanied final cooling of the skarnoid and prograde minerals were altered by antigorite (after forsterite), clinozoisite (iron poor epidote) and clinochlore
(magnesian chlorite). Chalcopyrite was deposited during this cooling stage and accompanied the retrograde
alteration, therefore, chalcopyrite replaces magnetite and overgrows and replaces the silicate and carbonate
minerals.
MINERALIZED ZONE:
Name: No.2 zone Thickness: 2.7 m Length: n/a Strike: 2700 Dip: 900 Shape: Irregular
Structure: Contact Character: Podiform
Classification: Contact metamorphism, hydrothermal, skarnoid
ASSESSMENT FILES (Kenora Resident Geologist office):
52L07NW D-3.
ASSAYS:
Sample No. Rock Name
Au
(ppb)
Ag
(ppm)
Mo
(ppm)
As
(ppm)
Cr
(ppm)
Co
(ppm)
Ni
(ppm)
Cu
(ppm)
Zn
(ppm)
94JRP1137
u/m rock
128
11
22.61
< 100
84
218.8
141
1.8%
98.49
94JRP1138
u/m rock
<3
4.4
<8
<6
86
102
< 40
109
60.9
94JRP1139
u/m rock
96
7
12.16
< 100
75
149.1
< 40
0.6%
86.45
94JRP1140
u/m rock
68
4
<8
<6
89
151
46
0.62%
88.9
94JRP1141
u/m rock
634
7.2
<8
<6
24
375
190
6.5%
201
94JRP1142
calcsilicate
rock
133
5
<8
<6
89
132
92
0.72%
145
94JRP1143
calcsilicate
rock
6
3.6
20.7
<6
36
39.8
47
598
45.5
u/m - ultramafic
104
7. DEPOSIT NAME: DOME No. 3 OCCURRENCE (WERNER LAKE NICKEL
OCCURRENCE)
COMMODITIES: Ni, Cr, Cu
UTM COORDINATES: 367735.0 mE, 5590511.0 mN
UTM Datum: NAD27
MDI No.: MDI52L07NW00037
Mining Division: Kenora
Area Name: Werner Lake
UTM ZONE: 15
Claim Map No.: G-2654
Mining Location: KRL 19136
LOCATION AND ACCESS:
The occurrence is accessible from Werner Lake. Drive down the Gordon Lake mine road to the north shore of
Werner Lake. Launch a canoe at the large culvert. Paddle east along the north shore of the lake to the mouth
of Upper Falls creek. Two large trenches are located a few metres inland on the east shore of the creek. The
trenches are about 18 m long and 2 m wide and are obscured by brush and alders.
EXPLORATION HISTORY:
1942-- 1945: Dome Exploration Canada Ltd. conducted prospecting, trenching, stripping, sampling and ground
geophysical surveys over the property. Thirty-two short diamond-drill holes totalling 3760 feet were completed at the No. 3 or “Main showing” occurrence.
1955: The property was acquired by Werner Lake Nickel Mines, Ltd. who conducted ground geophysical surveys and completed about 4000 feet of diamond drilling.
1966-- 1971: Consolidated Canadian Faraday Ltd. diamond drilled 4 holes totalling 1373 feet.
GEOLOGICAL DESCRIPTION:
Province: Superior
Subprovince: English River
Assemblage: English River
Metamorphism: 1) Type: Regional
2) Grade: Upper amphibolite to granulite
The Dome No. 3 occurrence is situated on the Werner-- Rex lakes fault that extends along the contact between a
metasedimentary migmatite assemblage to the north and the tonalitic Marijane batholith. The fault strikes east
across the Manitoba-- Ontario provincial border through Reynar, Almo, Gordon, Werner and Rex lakes to Bug
Lake and beyond for a strike length of approximately 32 km. The fault bifurcates into several fault splays at
the east end of Werner Lake. The fault strikes east and dips north at the Dome No. 3 property.
Deformed, metamorphosed and metasomatized gabbro, leucogabbro, anorthosite and ultramafic pods are situated within and adjacent to the Werner-- Rex lakes fault and may have originally been part of one stratiform,
layered intrusion. The ultramafic pods are relatively small, amphibolitized and recrystallized and host oxide
and sulphide minerals such as magnetite, chromite, pyrrhotite and chalcopyrite. The Dome No. 3 occurrence
consists of one of these small ultramafic pods.
LITHOLOGIC DESCRIPTION:
Ultramafic rocks: Dark green-grey to black, medium- to coarse-grained, amphibolitized and serpentinized
ultramafic rock contains “patches” of fine-grained, fibrous green actinolite; large (1 cm) dark green pyroxene
(?) crystals; coarse biotite; and some green muscovite Heavy garnet and biotite was also reported in the ultramafic rocks in drill core.
MINERAL DESCRIPTION:
Ultramafic rocks host about 30% combined magnetite and chromite and some red hematite staining. Sulphide
minerals are erratically distributed and consist of about 5% disseminated pyrrhotite; 2% disseminated pyrite;
and less than 1% chalcopyrite. Sulphide minerals are also concentrated along narrow fractures. Carlson
(1958) also reported that pentlandite was identified at the occurrence.
Several diamond-drill holes, completed by Dome Exploration, intersected mineralized sections that analyzed:
0.48% Ni across 63 feet; 0.38% Ni across 65 feet; 0.49% Ni across 15.5 feet; and 0.31% Ni across 53.5 feet.
Diamond drilling by Werner Lake Nickel Mines Ltd. delineated a 48 m long and 14 m wide mineralized zone
with an average grade of 0.40% Ni, 4.12% Cr and 1.76% Zn.
ALTERATION DESCRIPTION:
The primary mineralogy of the ultramafic rocks has been replaced by a prograde metamorphic mineral assemblage of actinolite-tremolite with retrograde alteration of amphibole to antigorite. The ultramafic rocks also
105
contain abundant coarse biotite which is a result of recrystallization of serpentinized ultramafic rocks by a
combination of metasomatic and metamorphic reactions between the ultramafic/mafic rocks, felsic country
rocks, pegmatites and peraluminous intrusive rocks.
MINERALIZED ZONE:
Name: No. 3 zone Length: 48.0 m Thickness: 15 m Strike: 2700 Dip: 800
Shape: Lens Structure: Fault Character: Podiform
Classification: Magmatic
ASSESSMENT FILES (Kenora Resident Geologist office):
52L07NW D-1, D-2, D-3, E-2 (A-4).
ASSAYS:
Sample No.
Rock
Name
Au
(ppb)
Ag
(ppm)
Pd
(ppb)
Pt
(ppb)
Cr
(ppm)
Co
(ppm)
Ni
(ppm)
Cu
(ppm)
Zn
(ppm)
94JRP1129
u/m rock
17
2
376
89
> 15000
337
0.40%
1191
116
u/m - ultramafic
Samples 94JRP1130, 1131 and 1132 were collected for whole rock geochemistry and analyzed 5.66% Cr2O3,
2.99% Cr2O3 and 7.05% Cr2O3, respectively.
106
8. DEPOSIT NAME: DOME No. 4 OCCURRENCE
COMMODITIES: Cu
UTM COORDINATES: 369288.0 mE, 5590586.0 mN
UTM Datum: NAD27
MDI No.: MDI52L07NW00047
Mining Division: Kenora
Area Name: Werner Lake
UTM ZONE: 15
Claim Map No.: G-2654
Mining Location: KRL 19132
LOCATION AND ACCESS:
The occurrence is located “just south” of the southwest end of Loon’s Nest Lake and is accessible by floatplane or by walking north from Werner Lake. The author did not locate this occurrence.
EXPLORATION HISTORY:
1942-- 1945: Dome Exploration Canada Ltd. conducted prospecting, trenching, sampling and ground geophysical surveys over a large claim group of 60 contiguous mining claims. Four trenches were sunk on the No. 4
occurrence over a strike length of about 900 feet. Two diamond-drill holes (DDH No.27 and No. 30) were
completed but no mineralization was intersected.
GEOLOGICAL DESCRIPTION:
Province: Superior
Subprovince: English River
Metamorphism: 1) Type: Regional
2) Grade: Granulite
Assemblage: English River
The Dome No. 4 occurrence is situated on a northeast-striking fault splay that extends from the Werner-- Rex
lakes fault at the east end of Werner Lake. The fault splay extends along the contact between a metasedimentary migmatite assemblage to the north and tonalitic rocks of the Marijane batholith.
The Dome No. 4 occurrence consists of metatexite at the contact with tonalitic rocks of the Marijane batholith.
LITHOLOGIC DESCRIPTION:
Migmatite: Metatexite with 40 to 90% moderately to strongly foliated wacke and pelitic paleosome is interlayered with medium- to coarse-grained granitoid and pegmatoid leucosome. Commonly intruded by late-tectonic pegmatitic granitic dikes.
MINERAL DESCRIPTION:
Sulphide minerals consist of disseminated pyrrhotite with minor chalcopyrite.
ALTERATION DESCRIPTION:
No information available.
MINERALIZED ZONE:
Name: No.4 zone Strike: 2630 Dip: 900 Character: Disseminated
Classification: Hydrothermal
ASSESSMENT FILES (Kenora Resident Geologist office):
52L07NW D-3.
107
9. DEPOSIT NAME: DUVAN OCCURRENCE
COMMODITIES: Cu
MDI No.: 52L07NE Claim Map No.: G-2637 Mining Division: Kenora Area Name: Rex Lake
LOCATION AND ACCESS:
The Duvan occurrence is located about 250 m north of Rex Lake which is only accessible by floatplane. The
trenches are situated north of a large boot-shaped bay on the north shore of the lake. Unfortunately, the author
could not locate the trenches.
EXPLORATION HISTORY:
1969: Duvan Copper Company Ltd. conducted geological mapping, trenching and sampling over a contiguous
group of 69 mining claims at the northeast end of Rex Lake.
1995: Staked by Canmine Resources Corporation.
GEOLOGICAL DESCRIPTION:
Province: Superior
Subprovince: English River
Metamorphism: 1) Type: Regional
2) Grade: Granulite
Assemblage: English River
The Duvan occurrence is located north of an east-northeast-striking fault splay that extends along the north
shore of Rex Lake. The fault splay may be the eastward continuation of the Werner-- Rex lakes fault that extends southeast from Werner Lake. A strong northeast-striking foliation occurs throughout the area. Folding
of the metasedimentary migmatite assemblage is best developed along the north shore of Rex Lake where
dominant, tight, S-style symmetric folds with east-northeast-striking axial planar foliations plunge moderately
to the northeast and east-northeast. Many of these folds contain asymmetric, second-order, parasitic folds
along their limbs. An east-northeast-striking, vertical, S2 mineral foliation is axial planar to folds at Rex Lake.
The Duvan occurrence is situated within diatexite and peraluminous granitoid rocks that contain discontinuous
pods and lenses of mafic gneiss and altered ultramafic and mafic intrusive rocks.
LITHOLOGIC DESCRIPTION:
Pink to white weathering diatexite and peraluminous granitoid rocks are the dominant lithologies in the vicinity of the Duvan occurrence and commonly host discontinuous lenses and pods of fine- to coarse-grained mafic
gneiss and coarse biotite-garnet schist. The mafic gneiss contains up to 80% garnet porphyroblasts. A strong
foliation strikes 2650 and dips steeply to the northeast. Abundant Z-drag folding was also observed in all rock
types.
MINERAL DESCRIPTION:
Little information is available on this occurrence. Chalcopyrite and pyrite occur in narrow stringers or are disseminated throughout the host rocks. Duvan Copper mapped the host rocks as quartz-feldspar granulite and a
mafic intrusive. Two samples collected from the occurrence by Duvan Copper analyzed 0.16% Cu and 0.02%
Cu.
ASSESSMENT FILES (Kenora Resident Geologist office):
52L07NE .B-1.
108
10. DEPOSIT NAME: EASTERN MINING AND SMELTING CORP. OCCURRENCE
COMMODITIES: Cu, Ni
UTM COORDINATES: 380972.0 mE, 5590361.0 mN
UTM Datum: NAD27
MDI No.: MDI52L07NE
Mining Division: Kenora
Area Name: Rex Lake
UTM ZONE: 15
Claim Map No.: G-2637
Mining Location: KRL 33382
LOCATION AND ACCESS:
Rex Lake is only accessible by floatplane. The Eastern Mining and Smelting occurrence is located on the
north shore of the lake and east of the mouth of a small creek. There is little exposure on the property and
trenches were not found by the author.
EXPLORATION HISTORY:
1948: Frederick Mining and Development Group made preliminary examinations of the Turcotte copper-nickel occurrences located on the north shore of Rex Lake.
1953: Quebec Nickel Corp. Ltd. diamond drilled numerous holes at this occurrence.
1962: Falconbridge Nickel Ltd. conducted a geological reconnaissance of the Rex Lake area.
GEOLOGICAL DESCRIPTION:
Province: Superior
Subprovince: English River
Metamorphism: 1) Type: Regional
2) Grade: Granulite
Assemblage: English River
The Eastern Mining and Smelting occurrence is located south of an east-northeast-striking fault splay that extends along the north shore of Rex Lake. The fault splay may be the eastward continuation of the Werner-- Rex
lakes fault that extends southeast from Werner Lake. A strong northeast-striking foliation occurs throughout
the area. Folding of the metasedimentary migmatite assemblage is best developed along the north shore of
Rex Lake where dominant, tight, S-style symmetric folds with east-northeast-striking axial planar foliations
plunge moderately to the northeast and east-northeast. Many of these folds contain asymmetric, second-order,
parasitic folds along their limbs. An east-northeast-striking, vertical, S2 mineral foliation is axial planar to
folds at Rex Lake.
The Eastern Mining and Smelting occurrence is situated within homogeneous and inhomogeneous diatexite
and peraluminous granitoid rocks that contain discontinuous pods and lenses of mafic gneiss and altered ultramafic and mafic intrusive rocks.
LITHOLOGIC DESCRIPTION:
Rocks in the vicinity of the occurrence consist of the following:
Mafic gneiss: Very strongly foliated (2350/750N) to gneissic, medium- to coarse-grained, mafic gneiss composed of biotite, amphibole, plagioclase and disseminated magnetite. The mafic gneiss has a characteristic
orange-brown weathered surface and contains thick layers of garnet or cordierite porphyroblasts. Intruded by
granitic pegmatite dikes and medium-grained granodiorite. The mafic gneiss contains some minor peraluminous garnet-cordierite-feldspar-quartz leucosome.
A leucocratic, quartz-rich gneiss is interlayered with the mafic gneiss. The leucocratic gneiss consists of finegrained biotite, orthopyroxene, plagioclase and quartz with disseminated pink garnets < 2 mm in size. The
gneiss also contains narrow magnetite veinlets.
Leucogabbro/anorthosite: A small outcrop of highly strained anorthositic gabbro is located on the lakeshore.
The anorthositic gabbro is epidotized and consists of recrystallized plagioclase, amphibole, orthopyroxene and
possible diopside. The anorthositic gabbro hosts narrow layers or bands of coarse, black amphibole with magnetite.
MINERAL DESCRIPTION:
Diamond drilling intersected fine- to coarse-grained, disseminated chalcopyrite, bornite, pyrite and pyrrhotite
in garnetiferous gneisses. The following intersections were reported: 0.31% and 0.46% Ni across 15 feet in
DDH 53; 0.13% Cu across 7.5 feet in DDH 54; and 0.77% Cu across 7 feet in DDH 56.
ALTERATION DESCRIPTION:
Epidotization of the anorthositic gabbro.
109
ASSESSMENT FILES (Kenora Resident Geologist office):
52L07NE E-2 (B-1), F-4, N-2 and S-2.
ASSAYS:
Sample No.
Rock Name
Au
ppb
Ag
pp
m
94JRP1010
leucocratic gneiss
**
2.7
Pd
Pt
ppb ppb
**
**
110
Cr
pp
m
Co
ppm
Ni
ppm
Cu
ppm
Mo
pp
m
Pb
pp
m
Zn
ppm
**
31.54 < 40 < 100
<8
**
32.77
11. DEPOSIT NAME: FALCONBRIDGE NORTH OCCURRENCE
COMMODITIES: Cu, Au
UTM COORDINATES: 379764.0 mE, 5590240.0 mN
UTM Datum: NAD27
MDI No.: MDI52L07NE00027
Mining Division: Kenora
Area Name: Rex Lake
UTM ZONE: 15
Claim Map No.: G-2637
LOCATION AND ACCESS:
Rex Lake is only accessible by floatplane. The Falconbridge North occurrence is located about 620 m northnortheast of the Radioactive Minerals Rex Lake occurrence on the north shore of Rex Lake.
EXPLORATION HISTORY:
1987: Falconbridge Limited optioned a contiguous group of 9 mining claims from R. Fairservice and R.
Knappet and conducted geological mapping and sampling. The company discovered weak, disseminated chalcopyrite mineralization in a garnet-biotite schist and diamond drilled 1 hole (FO-3) to a depth of 149 m at this
showing. The diamond-drill hole intersected trace amounts of chalcopyrite and pyrite.
GEOLOGICAL DESCRIPTION:
Province: Superior
Subprovince: English River
Metamorphism: 1) Type: Regional
2) Grade: Granulite
Assemblage: English River
The Falconbridge North occurrence is located north of an east-northeast-striking fault splay that extends along
the north shore of Rex Lake. The fault splay may be the eastward continuation of the Werner-- Rex lakes fault
that extends southeast from Werner Lake. A strong northeast-striking foliation occurs throughout the area.
Folding of the metasedimentary migmatite assemblage is best developed along the north shore of Rex Lake
where dominant, tight, S-style symmetric folds with east-northeast-striking axial planar foliations plunge moderately to the northeast and east-northeast. Many of these folds contain asymmetric, second-order, parasitic
folds along their limbs. An east-northeast-striking, vertical, S2 mineral foliation is axial planar to folds at Rex
Lake.
The Falconbridge North occurrence is situated within homogeneous and inhomogeneous diatexite and peraluminous granitoid rocks that contain discontinuous pods and lenses of mafic gneiss and altered ultramafic and
mafic intrusive rocks.
LITHOLOGIC DESCRIPTION:
The rocks in the vicinity of the Falconbridge North occurrence dominantly consist of strongly garnetiferous
diatexite and pegmatite dikes with lenses of garnetiferous mafic gneiss and ultramafic rocks. Diamond drilling
conducted by Falconbridge intersected garnet-plagioclase-biotite schist with narrow magnetite-garnet layers.
MINERAL DESCRIPTION:
The occurrence was not located by the author and assessment file information is sparse. Falconbridge reported
that a sample collected from a garnet-biotite schist containing 5% disseminated chalcopyrite blebs analyzed
0.75% Cu, 0.20 opt Ag and 0.07 opt Au. The diamond-drill hole that was completed at the occurrence contained trace amounts of sulphide mineralization.
ALTERATION DESCRIPTION:
Diamond drilling conducted by Falconbridge intersected variable epidote alteration in the gneisses.
ASSESSMENT FILES (Kenora Resident Geologist office):
52L07NE R-1and S-2.
111
12. DEPOSIT NAME: FREDERICK No. 1 OCCURRENCE
COMMODITIES: Cu, Ni
UTM COORDINATES: 382972.0 mE, 5591642.0 mN
UTM Datum: NAD27
MDI No.: MDI52L07NE00025
Mining Division: Kenora
Area Name: Rex Lake
UTM ZONE: 15
Claim Map No.: G-2637
LOCATION AND ACCESS:
Rex Lake is only accessible by floatplane. The Frederick No. 1 occurrence is located about 430 m northwest
of a small north-striking bay on the north shore of Rex Lake. A few overgrown and debris-filled trenches were
found by the author.
EXPLORATION HISTORY:
1948: Frederick Mining and Development Group conducted geological mapping and ground geophysical surveys over 3 separate sulphide occurrences north of Rex Lake.
1955: Quebec Nickel Corp. Ltd. diamond drilled 10 short holes at the No. 1 occurrence and completed some
trenching and stripping. Only minor chalcopyrite and pyrite were intersected in the diamond-drill holes.
1956: Eastern Mining and Smelting Corporation Ltd. diamond drilled 4 holes totalling 1668.1 feet. The holes
intersected garnetiferous gneisses and pegmatite with narrow sections of minor disseminated chalcopyrite and
pyrite. A few narrow sections of massive pyrite and pyrrhotite, hosted by white pegmatite, were also intersected in diamond-drill core.
1987: The property was optioned from R. Fairservice by Platinum Exploration Canada Inc. who conducted a
small ground magnetic geophysical survey over the occurrence. The company diamond drilled 3 holes totalling 466 feet. The drilling intersected narrow sulphide zones in garnetiferous gneisses, pegmatite and biotite
schists.
GEOLOGICAL DESCRIPTION:
Province: Superior
Subprovince: English River
Metamorphism: 1) Type: Regional
2) Grade: Granulite
Assemblage: English River
The Frederick No. 1 occurrence is located north of an east-northeast-striking fault splay that extends along the
north shore of Rex Lake. The fault splay may be the eastward continuation of the Werner-- Rex lakes fault that
extends southeast from Werner Lake. A strong northeast-striking foliation occurs throughout the area. Folding
of the metasedimentary migmatite assemblage is best developed along the north shore of Rex Lake where
dominant, tight, S-style symmetric folds with east-northeast-striking axial planar foliations plunge moderately
to the northeast and east-northeast. Many of these folds contain asymmetric, second-order, parasitic folds
along their limbs. An east-northeast-striking, vertical, S2 mineral foliation is axial planar to folds at Rex Lake.
The Frederick No. 1 occurrence is situated within homogeneous and inhomogeneous diatexite and peraluminous granitoid rocks that contain discontinuous pods and lenses of mafic gneiss and altered ultramafic and
mafic intrusive rocks.
LITHOLOGIC DESCRIPTION:
Pink to white weathering diatexite and peraluminous granitoid rocks are the dominant lithologies at the Frederick No. 1 occurrence. Discontinuous lenses and pods of fine- to coarse-grained amphibole, biotite-garnet
schist, ultramafic rock and pyroxene gabbro (orthopyroxene, clinopyroxene, plagioclase, biotite) are situated
within the diatexite. Up to 20% garnet porphyroblasts occur in all rock types. A strong foliation strikes 2640
and dips steeply to the north. Z-drag folding was observed in the diatexite.
MINERAL DESCRIPTION:
The highest reported copper and nickel values, intersected in diamond drilling, were 0.15% Cu and 0.10% Ni
across 1.5 feet. A few low silver values were also reported. Mineralization in the trenches was reported to
occur along the edge of a small scarp for approximately 70 feet. Assessment work reports by Frederick Mining
describe the mineralization in the trenches as “heavy” and consisting of pyrite, pyrrhotite and sphalerite (?) in
silicified paragneiss.
The author found a large rusty zone on the edge of a steep outcrop near low swampy ground. Abundant disseminated to semi-massive pyrite (10%), chalcopyrite (5%) and pyrrhotite (5%) were found in quartz-rich peg112
matite and gneiss. Massive (up to 80%) sulphide minerals also occur in foliation parallel, narrow (8 cm) bands
in the gneisses. Platinum Exploration reported minor graphite and galena within the granitoid rocks. Ultramafic rocks are mineralized with disseminated magnetite and pyrrhotite and minor chalcopyrite. Platinum
Exploration noted that the ultramafic rocks contained rhythmic layers of magnetite, pyrrhotite, biotite and garnet up to 4 cm wide. About 80% combined sulphide minerals occur in the ultramafic rocks. Samples collected
from the trenches by Platinum Exploration analyzed between 23 and 570 ppm Cu with minor Ni, Ag and Cr.
Diamond-drilling by Platinum Exploration intersected generally narrow, massive sulphide zones with ball and
breccia textures indicative of sulphide mineral remobilization. Diamond-drill hole RX-87-2 intersected 23 feet
of semi-massive pyrrhotite and pyrite in a chlorite-biotite schist.
ALTERATION DESCRIPTION
Host rocks appear to be partially silicified adjacent to strong sulphide mineralization. The ultramafic rocks are
biotitic, chloritic and garnetiferous due to alteration by metasomatism associated with the intrusion of the pegmatites and peraluminous granitoid rocks.
MINERALIZED ZONE:
Strike: 2640 Dip: 800 Shape: Irregular Structure: Foliation Character: Disseminated, veins
Classification: Magmatic, hydrothermal, remobilized
ASSESSMENT FILES (Kenora Resident Geologist office):
52L07NE C-1, C-5, D-1, F-1, Q-1 and Q-2.
ASSAYS:
Sample No.
Rock Name
Au
(ppb)
Ag
(ppm)
Mo
(ppm)
Pb
(ppm)
Cr
(ppm)
Co
(ppm)
Ni
(ppm)
Cu
(ppm)
Zn
(ppm)
94JRP1035
pegmatite
<3
<2
25.59
10
50
22.32
< 40
187
47.22
113
13. DEPOSIT NAME: FREDERICK No. 2 OCCURRENCE
COMMODITIES: Cu
UTM COORDINATES: 382925.0 mE, 5591598.0 mN
UTM Datum: NAD27
MDI No.: MDI52L07NE00028
Mining Division: Kenora
Area Name: Rex Lake
UTM ZONE: 15
Claim Map No.: G-2637
LOCATION AND ACCESS:
Rex Lake is only accessible by floatplane. The Frederick No. 2 occurrence is located at the northeast end of
Rex Lake. The occurrence is about 400 m northwest of the lake, however, the author was unable to find it.
EXPLORATION HISTORY:
1948: Frederick Mining and Development Group conducted geological mapping and ground geophysical surveys over 3 separate sulphide occurrences north of Rex Lake.
1956: Three Brothers Mining Exploration diamond drilled 1 hole totalling 485 feet. The hole intersected biotite gneisses and pegmatite with narrow sections of disseminated pyrrhotite and pyrite in pegmatite.
1987: The property was optioned from R. Fairservice by Platinum Exploration Canada Inc. who conducted a
small ground magnetic geophysical survey over the occurrence.
GEOLOGICAL DESCRIPTION:
Province: Superior
Subprovince: English River
Metamorphism: 1) Type: Regional
2) Grade: Granulite
Assemblage: English River
The Frederick No. 2 occurrence is located south of an east-northeast-striking fault splay that extends along the
north shore of Rex Lake. The fault splay may be the eastward continuation of the Werner-- Rex lakes fault that
extends southeast from Werner Lake. A strong northeast-striking foliation occurs throughout the area. Folding
of the metasedimentary migmatite assemblage is best developed along the north shore of Rex Lake where
dominant, tight, S-style symmetric folds with east-northeast-striking axial planar foliations plunge moderately
to the northeast and east-northeast. Many of these folds contain asymmetric, second-order, parasitic folds
along their limbs. An east-northeast-striking, vertical, S2 mineral foliation is axial planar to folds at Rex Lake.
The Frederick No. 2 occurrence is situated within homogeneous and inhomogeneous diatexite and peraluminous granitoid rocks that contain discontinuous pods and lenses of mafic gneiss and altered ultramafic and
mafic intrusive rocks.
LITHOLOGIC DESCRIPTION:
Pink to white weathering, medium- to coarse-grained, diatexite, peraluminous granitoid rocks and quartz-feldspar-biotite pegmatite dikes are the dominant lithologies at the Frederick No. 2 occurrence. Paleosome in the
diatexite contains 10 to 25% garnet porphyroblasts.
MINERAL DESCRIPTION:
Sulphide mineralization was reported to occur intermittently along the edge of a large scarp for approximately
200 feet. Assessment work reports describe the mineralization as coarse disseminated pyrite in silicified paragneisses.
MINERAL DESCRIPTION:
Possible silicification associated with the sulphide mineralization.
ASSESSMENT FILES (Kenora Resident Geologist office):
52L07NE D-1, J-1, Q-1 and Q-2.
114
14. DEPOSIT NAME: FREDERICK No. 3 OCCURRENCE
COMMODITIES: Cu
UTM COORDINATES: 384778.0 mE, 5591483.0 mN
UTM Datum: NAD27
MDI No.: 52L07NE
Mining Division: Kenora
Area Name: Rex Lake
UTM ZONE: 15
Claim Map No.: G-2637
LOCATION AND ACCESS:
Rex Lake is only accessible by floatplane. The Frederick No. 3 occurrence is located at the northeast end of
Rex Lake. The occurrence consists of several large rusty outcrops on the north shore of the lake beside the
mouth of a small creek. The occurrence is visible from the lake.
EXPLORATION HISTORY:
1948: Frederick Mining and Development Group conducted geological mapping and ground geophysical surveys over 3 separate sulphide occurrences north of Rex Lake.
1956: Three Brothers Mining Exploration diamond drilled 7 holes totalling 1288 feet. The holes intersected
biotite gneisses and pegmatite with narrow sections of disseminated and massive sulphide minerals. Eastern
Mining and Smelting Corp. Ltd. diamond drilled 2 holes totalling 963 feet on the south shore of Rex Lake,
across from the No. 3 occurrence.
1987: The property was optioned from R. Fairservice by Platinum Exploration Canada Inc. who conducted a
small ground magnetic geophysical survey on the property. The company diamond drilled 1 hole to 134 feet.
The drilling intersected narrow sulphide zones in garnetiferous gneisses, pegmatite, amphibole-rich rock and
biotite-graphite-pyrite schists.
GEOLOGICAL DESCRIPTION:
Province: Superior
Subprovince: English River
Metamorphism: 1) Type: Regional
2) Grade: Granulite
Assemblage: English River
The Frederick No. 3 occurrence is located south of an east-northeast-striking fault splay that extends along the
north shore of Rex Lake. The fault splay may be the eastward continuation of the Werner-- Rex lakes fault that
extends southeast from Werner Lake. A strong northeast-striking foliation occurs throughout the area. Folding
of the metasedimentary migmatite assemblage is best developed along the north shore of Rex Lake where
dominant, tight, S-style symmetric folds with east-northeast-striking axial planar foliations plunge moderately
to the northeast and east-northeast. Many of these folds contain asymmetric, second-order, parasitic folds
along their limbs. An east-northeast-striking, vertical, S2 mineral foliation is axial planar to folds at Rex Lake.
The Frederick No. 3 occurrence is situated within homogeneous and inhomogeneous diatexite and peraluminous granitoid rocks that contain discontinuous pods and lenses of mafic gneiss and altered ultramafic and
mafic intrusive rocks.
LITHOLOGIC DESCRIPTION:
Pink to white weathering, medium- to coarse-grained, diatexite, peraluminous granitoid rocks and quartz-feldspar-biotite pegmatite dikes are the dominant lithologies at the Frederick No. 3 occurrence. Paleosome in the
diatexite contains 10 to 25% garnet porphyroblasts.
MINERAL DESCRIPTION:
Outcrops at the occurrence are deeply weathered and gossan-stained. About 10% fine-grained pyrite is disseminated throughout a garnetiferous and siliceous wacke paleosome. The paleosome is intruded by quartzrich pegmatite and some minor quartz veins. Pegmatite contains between 15 and 25% pyrite and 1 to 2% chalcopyrite on narrow fractures. Some mineralized sections contain more than 80% combined sulphide minerals
in narrow layers or veins.
Diamond drilling by Platinum Exploration intersected disseminated to semi-massive sulphide mineralization
(up to 70%) in almost every rock type. Disseminated graphite was reported in the gneisses.
ALTERATION DESCRIPTION:
Silicification is associated with the sulphide mineralization as well as some chloritization.
MINERALIZED ZONE:
Shape: Irregular Structure: Fractures, foliation Character: Disseminated
115
Classification: Hydrothermal, remobilized
ASSESSMENT FILES (Kenora Resident Geologist office):
52L07NE C-2, D-1, J-1, Q-1 and Q-2.
ASSAYS:
Sample No.
Rock Name
Au
(ppb)
Ag
(ppm)
Mo
(ppm)
Pb
(ppm)
Cr
(ppm)
Co
(ppm)
Ni
(ppm)
Cu
(ppm)
Zn
(ppm)
94JRP1005
migmatite
<3
2.4
9.69
9
32
<5
< 40
120
12.81
94JRP1045
pegmatoid
<3
<2
9.39
17
99
7.67
< 40
131
151.2
94JRP1046
migmatite
<3
<2
10.03
<7
202
15.59
47
203
74.61
94JRP1047
pegmatoid
<3
<2
9.93
21
62
89.99
< 40
129
34
116
15. DEPOSIT NAME: GORDON LAKE MINE (REXORA No. 2)
COMMODITIES: Ni, Cu, Pd, Pt, Ag, Au
UTM COORDINATES: 362917.0 mE, 5591776.0 mN
UTM Datum: NAD27
MDI No.: MDI52L07NW00004
Mining Division: Kenora
Area Name: Werner Lake
31825; 31830 to 31832; 19096, 19097, 33210
UTM ZONE: 15
Claim Map No.: G-2654
Mining Locations: KRL 31823 to
LOCATION AND ACCESS:
The Gordon Lake mine site can be accessed from the Gordon Lake mine road which leads directly to the property. A mine gate, which is usually locked, is installed on the road.
EXPLORATION HISTORY:
1942: H. Byberg and A. Vanderbrink discovered nickel-copper mineralization in ultramafic rocks on the
southwest shore of Gordon (Lynx) Lake.
1942 – 1945: Noranda Mines Ltd. optioned the Gordon Lake property and conducted extensive ground geophysical surveys and diamond drilling during World War II.
1948-- 1949: Rexora Mining Corporation Ltd. acquired the east part of the Gordon Lake property while the
International Nickel Company of Canada Ltd acquired the west part. Both companies conducted diamond drilling and geophysical surveys on their claims. Rexora had outlined 2 mineralized zones with small tonnages,
these were: the Rexora No.5 zone at Werner Lake with 35 000 tons averaging 0.78% Ni and 0.42% Cu; and the
Rexora No.2 zone on the southwest shore of Gordon Lake with 140 000 tons averaging 1.53% Ni and 0.73%
Cu. Falconbridge Nickel Mines Ltd. optioned the Rexora properties and conducted more diamond drilling and
ground geophysical surveys until 1949.
1952-- 1958: Quebec Nickel Corporation acquired all the ground formerly explored by Noranda, Inco, Rexora
and Falconbridge. Quebec Nickel conducted an extensive surface diamond drilling program followed by the
sinking of 2 shafts with considerable underground exploration and development. The Quebec Nickel Corporation merged with the Eastern Smelting and Mining Corporation to form Eastern Mining and Smelting Corporation Ltd. in 1955 but the name was changed to the Nickel Mining and Smelting Corporation Ltd. in 1958.
1962-- 1969: Nickel Mining and Smelting Corporation Ltd. was reorganised in 1963 to form Metal Mines Ltd.
and reorganised again in 1967 to form Consolidated Canadian Faraday Ltd. The Gordon Lake Mine commenced production in 1962 and produced 1 370 285 tons averaging 0.92% Ni, 0.47% Cu, 0.004 opt Pt and
0.023 opt Pd until 1969 when underground operations were terminated and the shafts were closed. Some minor production continued until 1972 when the mill was finally closed.
1971: It was reported that the mine had reserves of 170 420 tonnes averaging 0.85% Ni and 0.35% Cu (The
Financial Post Corporation Service (1974) Consolidated Canadian Faraday Ltd.).
1994: The mine site was rehabilitated.
GEOLOGICAL DESCRIPTION:
Province: Superior
Subprovince: English River
Metamorphism: 1) Type: Regional
2) Grade: Amphibolite
Assemblage: English River
The Gordon Lake Mine is situated along the east-striking, vertical to north-dipping Werner-- Rex lakes fault
that extends along the contact between metasedimentary migmatite to the north and tonalitic rocks of the Marijane batholith to the south. The fault strikes east across the Manitoba-- Ontario provincial boundary through
Reynar, Almo, Gordon, Werner and Rex lakes to Bug Lake and beyond for a strike length of about 32 km. The
fault bifurcates into several fault splays at the east end of Werner Lake and the east end of Reynar Lake. Overall horizontal displacement along the fault is interpreted to be dextral. Mineral lineations along the south shore
of Almo Lake have shallow plunges to the west-northwest.
Deformed, metamorphosed and metasomatized gabbro, leucogabbro, anorthosite and ultramafic pods are situated within and adjacent to the Werner-- Rex lakes fault and may have originally been part of one stratiform,
layered intrusion. The ultramafic pods are relatively small, amphibolitized and recrystallized and host oxide
and sulphide minerals such as magnetite, chromite, pyrrhotite and chalcopyrite. The Gordon Lake Mine consists of several disconnected ultramafic pods, lenses and pipe-like masses located along the Werner-- Rex lakes
fault. The pods are 180 m x 45 m x 180 m in size and are elongated parallel to the strike of the fault. The
pods are elliptical, north-dipping, northwest-plunging bodies that have greater vertical than lateral extent. The
117
footwall of the mine consists of mylonitized tonalite-granodiorite of the Marijane batholith. The hanging wall
consists of metasedimentary migmatite.
The interior of the ultramafic pods at the Gordon Lake Mine are relatively undeformed with a weak preferred
orientation of platy and acicular minerals, however, platy biotite crystals along the margins of the pods show
strong preferred orientations aligned parallel to sheared ultramafic contacts against the country rocks.
LITHOLOGIC DESCRIPTION:
The ultramafic rocks at the mine have been classified as hornblende peridotites, peridotitic hornblendites and
peridotites based on their mineralogy. Scoates (1972) examined the relatively unaltered cores of the large
ultramafic pods and reported that the original primary igneous mineralogy consists of olivine (Fo73.8 to Fo85.1 ;
average Fo79.8), orthopyroxene (En76 to En92 ; average En85.5), hornblende, chrome spinel (picotite) and minor
clinopyroxene which indicates that the rocks are essentially olivine-orthopyroxene-chromite cumulates. Original mineralogy and primary igneous textures in the majority of ultramafic pods have been obscured and modified by serpentinization, replacement, recrystallization and several periods of metasomatism and metamorphism associated with the intrusion of granitic and pegmatitic rocks. The altered ultramafic rocks are almost
completely composed of metamorphic amphibole (actinolite-tremolite, hornblende, anthophyllite), secondary
magnetite and remnant chrome spinel with variable amounts of serpentine and talc and other secondary minerals such as chlorite, clinochlore, biotite, phlogopite, calcite and hercynite (dark green iron spinel).
The most common amphibole in the ultramafic rocks is dark green actinolite-tremolite that occurs as elongate,
acicular crystals and radiating patches of crystals with highly variable grain sizes ranging from 1 mm to 10
cm. Samples of ultramafic rock from waste dumps at the Gordon Lake Mine contain actinolite crystals up to
30 cm in length. Other amphiboles such as hornblende occur as stubby black crystals while anthophyllite occurs as long lath-like crystals with feathery terminations (Scoates1972). All amphiboles are variably altered to
chlorite and serpentine. Orthopyroxene occurs as stubby or blocky, dark brown to black crystals with ragged
crystal boundaries due to serpentinization. Coarse-grained, chloritic biotite occurs along the margins of the
ultramafic pods or in alteration halos adjacent to pegmatite dikes and peraluminous pegmatoid veins that intrude the ultramafic rocks.
The footwall tonalite-granodiorite is medium-grained, relatively equigranular, pink-grey with diffuse pegmatitic or pink granitic patches. The tonalite is very strongly foliated with narrow (< 20 cm) mylonite zones and a
common gneissic texture with mafic platy minerals segregated into layers. The tonalite commonly hosts xenoliths of gabbro and ultramafic rock and late pegmatite dikes.
The migmatite in the hanging wall is a massive, medium- to coarse-grained, homogeneous diatexite consisting
of pink-white weathering granitoid and pegmatoid material with less than 10% strongly foliated wacke and
pelitic paleosome. The migmatite may contain 5-25% red-brown garnet porphyroblasts and 0-5% cordierite
porphyroblasts.
MINERAL DESCRIPTION:
The mineralized ultramafic bodies at the Gordon Lake Mine are not exposed, therefore, the following descriptions and observations of the mineralization at the mine have been summarized from Scoates (1963, 1972).
There are 2 types of sulphide mineralization at the mine: 1) disseminated copper-nickel sulphides in ultramafic
rocks; and 2) breccia sulphides in “amphibolite” (Scoates 1972).
Disseminated Sulphide Mineralization
a) Diffuse
This type of mineralization consists of greater than 5% total sulphide minerals in recrystallized margins of
ultramafic pods. Fine-grained, diffuse sulphide minerals with ragged, irregular, grain boundaries occur in fine,
discontinuous, sulphide stringers or in delicate “net textures”. Sulphide minerals consist of pyrrhotite and
chalcopyrite with minor pentlandite, cubanite and violarite. Pentlandite is always closely associated with pyrrhotite and cubanite occurs as inclusions in chalcopyrite and pentlandite. Sulphide grains commonly have globule or droplet shapes.
b) Interstitial
Disseminated, interstitial sulphide mineralization occurs in relatively unaltered cores of the ultramafic pods.
Sulphide minerals are medium-grained and commonly interstitial to amphibole with little evidence for sulphide replacement of silicate minerals. Pyrrhotite is the most common sulphide mineral and is commonly intergrown with pentlandite. Pyrrhotite is also interstitial to chromite grains and may occur as small inclusions
118
in the chromite. Chalcopyrite occurs as irregular, discrete grains or in patches associated with pyrrhotite and
pentlandite. Cubanite occurs as inclusions in chalcopyrite. Magnetite grains commonly occur along the rims
of sulphide minerals.
Analyses of the disseminated sulphide ores from the A-peridotite orebody gave numerous, low to moderate Rh,
Pd and Pt values such as: 0.23 ounce Rh per ton; 4.40 ounces Pd per ton and 0.34 ounce Pt per ton (Scoates
1963, Table 40, p.150). Jonasson et al. (1987) reported average analytical values of 1165 ppb Pt and 4385 ppb
Pd from 3 samples collected at the mine.
Breccia Sulphide Mineralization
Breccia ore occurs in the B-breccia zone which is a discontinuous, linear, sinuous, band of massive sulphide
minerals enclosed within “amphibolite” (Scoates 1972). The breccia zone is parallel to the Werner-- Rex lakes
fault and is situated 3 to 12 m south of the fault. The B-breccia zone is approximately 600 m long in the upper
levels of the mine and 90 m long on the 1650-level with a vertical dimension of 400 m. Therefore, the B-breccia zone has a crude wedge-- shape in longitudinal section with the apex pointing downward. The B-breccia
zone is a series of discontinuous breccia sulphide zones ranging in width from a few centimetres to 3 m. The
zone is foliation parallel and conformable with enclosing gneissic rocks with sharp and distinct contacts that
are marked by a thin biotite selvage in the wall rocks. The breccia zone also has a close spatial association
with pegmatite dikes. The zone truncates pegmatite dikes and is also intruded by pegmatite. The B-breccia
zone also transects the A-peridotite orebody on 2 levels and terminates at the bottom of the A-peridotite.
Tongues of massive sulphide protrude from the peridotite into the B-breccia zone.
The breccia ore displays a well-developed ball-texture indicative of solid state remobilization of the sulphide
minerals. The zone contains rounded, subrounded to subangular fragments of a wide variety of rocks types
embedded in a sulphide matrix. Fragments dominantly consist of granodiorite-quartz diorite and range from a
few millimetres to 4 cm in size. Inclusions of pegmatite and “amphibolite” are 0.6 m to 0.9 m long and 0.3 m
to 0.6 m wide. Foliation in some “amphibolite” clasts is parallel to the foliation in the enclosing “amphibolite”
(Scoates 1972).
The B-breccia zone is dominantly composed of pyrrhotite, pentlandite and chalcopyrite with minor pyrite,
marcasite, molybdenite and cassiterite. The sulphide minerals are variably distributed throughout the zone.
The breccia ore does not contain magnetite; has more abundant pentlandite; and more abundant pyrite than the
disseminated ore. The average composition of massive sulphide ore in the B-breccia zone is: 37.93% S,
6.99% Ni, 0.08% Cu and 55.0% Fe. All of the ores at the mine average less than 2% Cu. Analyses of the sulphide ores from the B-breccia zone gave numerous high Rh, Pd and Pt values such as: 0.97 ounce Rh per ton;
6.96 ounces Pd per ton and 2.74 ounces Pt per ton (Scoates 1963, Table 40, p.150).
Lenses of massive sulphide in the A and G peridotite pods display mineral textures that are similar to the Bbreccia zone.
Mineralization in Migmatite
Massive lenses of chalcopyrite, 8 mm to 20 cm wide and 3 m long, occur in horizontal joint sets in the metasedimentary migmatite at the mine. The migmatite also hosts small lenticular pods (0.6 m x 0.3 m x 0.3m) of
coarse-grained hornblendite containing disseminated pyrite, chalcopyrite, pyrrhotite and molybdenite.
Metal ratio and sulphur isotope work by Scoates (1963, 1972) indicates that there is an “intimate genetic relationship” between the sulphide ores in the B-breccia zone and the A-peridotite orebody. Scoates (1972) concluded that the B-breccia zone consists of magmatic sulphide mineralization that was remobilized from the
ultramafic rocks into a structurally controlled zone developed parallel to the Werner-- Rex lakes fault.
ALTERATION DESCRIPTION:
Alteration of the ultramafic rocks consists of the replacement of mafic silicate minerals, such as olivine and
pyroxene, by serpentine minerals. The ultramafic rocks experienced at least 2 separate serpentinization events
consisting of 1) serpentinization during the initial cooling of the ultramafic rocks (Scoates 1972); and 2) a later, higher temperature serpentinization after the rocks were recrystallized to amphibole (Scoates 1972). Serpentine from the original serpentinization of the ultramafic rocks was recognized by Scoates (1972) in the
weakly altered cores of large pods at the Gordon Lake Mine. Antigorite is the predominant serpentine mineral
with minor amounts of bastite (after pyroxene).
A common characteristic of the ultramafic rocks are the presence of symmetric, monomineralic contact reaction zones (“blackwall zones”) along the margins of the pods and in alteration halos adjacent to pegmatite
dikes and peraluminous pegmatoid veins that intrude the ultramafic rocks (Scoates 1972). The reaction zones
119
of large pods surround a serpentinized but relatively unaltered core. The outer contact reaction zones consist
of coarse-grained, variably chloritic biotite selvages that range from a few centimetres to 1.5 m thick and are
developed between the ultramafic rocks and the felsic country rocks. The outer biotite zones form due to high
temperatures of metasomatism or addition of K2O from adjacent country rocks with high K2O contents (Bowes
1964; Fowler et al. 1981). Detailed work by Scoates (1972) has shown that the biotitic outer zones have a
sharp contact with an inner zone of medium- to coarse-grained amphibole that grades into the serpentinized
ultramafic mineral assemblage. The amphibole zones range in width from a few centimetres to 2 m (Scoates
1972) and may have formed due to a contribution of Al from the country rocks (Fowler et al. 1981; Curtis and
Brown 1969). A zone of talc development may occur between the amphibole zone and the serpentinized ultramafic rock and some sulphide minerals may be disseminated along the biotite zone/amphibole zone contact
(Scoates 1972). The reaction zones “protect” the centres of large ultramafic pods from further alteration and
deformation.
MINERALIZED ZONE:
Name: several Length: < 180m Thickness: < 45m Strike: 2700 Dip: 800 Plunge: west-northwest
Shape: Cylinder, pipe, tabular or sheet, wedge Structure: Fault Character: Podiform, pipe, sheet
Classification: Magmatic, remobilized
PAST PRODUCTION:
YEAR
Ore
Hoisted
(tons)
Ore
Milled
(tons)
Ni
(pounds)
Cu
(pounds)
Pt
(ounces)
Pd
(ounces)
Au
(ounces)
Ag
(ounces)
1962
33 135
45 170
584 567
251 461
**
**
**
**
1963
136 720
136 970
2 761 234
1 218 830
754
5042
**
**
1964
193 174
192 874
3 089 907
1 529 110
853
5154
853
5051
1965
184 464
184 364
3 210 604
1 642 933
875
6207
847
6318
1966
209 888
211 228
4 054 060
2 127 881
**
**
**
**
1967
220 690
214 536
3 906 731
2 251 317
891
6267
**
**
1968
207 331
207 417
3 133 094
1 732 535
850
5777
**
**
1969
177 736
177 726
1 974 830
1 051 462
**
3783
**
**
TOTAL
1 363 138
1 370 285
4223
32 230
1700
11 369
1970
**
105 504
1 121 764
593 284
**
1730
**
**
1971
**
99 731
1 147 606
560 865
**
1566
**
**
1972
**
56 696
618 906
342 158
**
838
**
**
TOTAL
1 363 138
1 632 216
4223
36 364
1700
11 369
22 775 027 11 805 534
25 663 303 13 301 841
Underground production was terminated in 1969. The production reported from 1970-- 1972 came from cleanup operations, etc..
120
COMMODITY
ORE MILLED
Nickel
Copper
Palladium
Platinum
1 370 285 tons
AVERAGE GRADE
0.92%
0.47%
0.023 opt
0.004 opt
Ore reserves were reported as 170 420 tonnes averaging 0.85% Ni and 0.35% Cu in 1971.
SOURCES: ODM Annual Reports (v.73, p.106; v.74 p.107; v.75, p.106; v.77, p.82-- 83; v.78, p.55)
The Financial Post Corporation Service (1970) Consolidated Canadian Faraday Ltd.
Revised July 9,1970, published by MacLean Hunter Publishing Co. Ltd.
The Financial Post Corporation Service (1974) Consolidated Canadian Faraday Ltd.
Revised January 21,1974, published by MacLean Hunter Publishing Co. Ltd.
NOTE:
The author recalculated average grade for Ni, Cu, Pd, Pt and Ag using the numbers above for
the period 1962 to 1969. The “new” average grade for nickel, indicated in the table above, is
higher than previously published figures.
ASSESSMENT FILES (Kenora Resident Geologist office):
52L07NW S-2, J-1, M-1, N-1, O-1 and E-2 (A-4, A-6, A-10, B-1 to B-12)
121
16. DEPOSIT NAME: JANET LAKE OCCURRENCE (CONTACT LAKE OCCURRENCE)
COMMODITIES: Cu
MDI No.: 52L07NW Claim Map No.: G-2654 Mining Division: Kenora Area Name: Werner Lake
LOCATION AND ACCESS:
The property is located immediately south of Janet (Contact) Lake which is the first small east-striking lake
due east of Werner Lake. The trenches were not located by the author.
EXPLORATION HISTORY:
1948: International Nickel Co. Ltd. conducted geological mapping and ground geophysical surveys at Janet
Lake. Copper and nickel values were reported to have been obtained from mafic rocks in a “sedimentary
band” east of Janet Lake.
1954: Quebec Nickel Corporation Ltd. diamond drilled 4 holes totalling 300 feet on a small pond east of Janet
Lake.
1955: Quebec Nickel Corporation Ltd. diamond drilled 8 holes totalling 1097 feet east-northeast of Janet
Lake.
1956: Eastern Mining and Smelting Corporation Ltd. diamond drilled 2 holes totalling 370.1 feet along the
south shore of Janet Lake.
1963: Nickel Mining and Smelting Corporation diamond drilled 2 holes totalling 724 feet along the south
shore of Janet Lake.
1995: Staked by Canmine Resources Corporation.
GEOLOGICAL DESCRIPTION:
Province: Superior
Subprovince: English River
Metamorphism: 1) Type: Regional
2) Grade: Amphibolite
Assemblage: English River
The Janet Lake occurrence is located immediately south of the east-striking Werner-- Rex lakes fault and is situated within tonalitic to granodioritic rocks at the north contact of the Marijane batholith.
LITHOLOGIC DESCRIPTION:
Lithologies intersected in diamond-drill core are described as paragneiss with pegmatite bands and short sections of biotite-hornblende gneiss. The rocks south of Janet Lake consist of massive, medium- to coarsegrained tonalitic to granodioritic rocks with xenoliths of metasedimentary rock and amphibolitized mafic
rocks. The tonalite also contains small mafic clots of actinolite, magnetite and biotite.
MINERAL DESCRIPTION:
Fine-grained and relatively sparse, disseminated pyrite, chalcopyrite and magnetite were reported in diamonddrill core.
ASSESSMENT FILES (Kenora Resident Geologist office):
52L07NW F-1, J-2, L-3, N-3 and N-4.
122
17. DEPOSIT NAME: KRL 33380/33381 OCCURRENCE
COMMODITIES: Cu
UTM COORDINATES: 380641.0 mE, 5590307.0 mN
UTM Datum: NAD27
MDI No.: MDI52L07NE
Mining Division: Kenora
Area Name: Rex Lake
UTM ZONE: 15
Claim Map No.: G-2637
Mining Location: KRL 33381
LOCATION AND ACCESS:
Rex Lake is only accessible by floatplane. The KRL 33380/33381 occurrence is located on the north shore of
the lake near the mouth of a small creek. There is poor outcrop exposure on the property. Trenches located
about 300 feet north of the lake, near the claim boundary between KRL 33380 and 33381, were not found by
the author.
EXPLORATION HISTORY:
1948: Frederick Mining and Development Group made preliminary examinations of the Turcotte copper-nickel occurrences located on the north shore of Rex Lake.
1953: Quebec Nickel Corp. Ltd. diamond drilled 5 holes at the occurrence. The holes intersected paragneiss,
pegmatite and biotite-amphibole schists with sections of disseminated and massive chalcopyrite and pyrite.
1962: Falconbridge Nickel Ltd. conducted a geological reconnaissance of the Rex Lake area.
1987: Falconbridge Limited optioned a contiguous group of 9 mining claims from R. Fairservice and R.
Knappet and conducted geological mapping and sampling.
GEOLOGICAL DESCRIPTION:
Province: Superior
Subprovince: English River
Assemblage: English River
Metamorphism: 1) Type: Regional
2) Grade: Granulite
The KRL 33380/33381 occurrence is located south of an east-northeast-striking fault splay that extends along
the north shore of Rex Lake. The fault splay may be the eastward continuation of the Werner-- Rex lakes fault
that extends southeast from Werner Lake. A strong northeast-striking foliation occurs throughout the area.
Folding of the metasedimentary migmatite assemblage is best developed along the north shore of Rex Lake
where dominant, tight, S-style symmetric folds with east-northeast-striking axial planar foliations plunge moderately to the northeast and east-northeast. Many of these folds contain asymmetric, second-order, parasitic
folds along their limbs. An east-northeast-striking, vertical, S2 mineral foliation is axial planar to folds at Rex
Lake.
The KRL 33380/33381 occurrence is situated within homogeneous and inhomogeneous diatexite and peraluminous granitoid rocks that contain discontinuous pods and lenses of mafic gneiss and altered ultramafic and
mafic intrusive rocks.
LITHOLOGIC DESCRIPTION:
Orthopyroxene-cordierite rock: A coarse orthopyroxene-cordierite rock with disseminated magnetite, minor
biotite and alternating garnet-rich and cordierite-rich layers. Garnet and orthopyroxene porphyroblasts are up
to 2.5 cm in size. Garnet and cordierite abundance commonly exceeds 80%.
Foliated 2550 with a steep dip to the north.
The orthopyroxene-cordierite-garnet rock is commonly interlayered with fine-grained mafic gneiss and intruded by pegmatitic peraluminous leucosome which also contains cordierite, garnet and orthopyroxene. The
rocks are also intruded by massive, coarse-grained, pink to white weathering granitic pegmatite dikes.
Company reports indicate that a “typical” mineralized peridotite was exposed on the property.
MINERAL DESCRIPTION:
Diamond-drill logs indicate “fair to weak” disseminated chalcopyrite and pyrite mineralization in garnetiferous
gneiss. DDH R-- 10 (Quebec Nickel) intersected 0.23% Cu across 6.5 feet and minor silver values. Reports in
the assessment files indicate that a “band of siliceous paragneiss in contact with a typical peridotite” was exposed about 300 feet north of the lake shore. Trenches on the peridotite exposed “excellent” chalcopyrite and
pyrrhotite mineralization that analyzed 8.0% Cu.
ALTERATION DESCRIPTION:
The orthopyroxene-cordierite-garnet rock may be a highly altered, metasomatized and metamorphosed ultramafic rock.
123
ASSESSMENT FILES (Kenora Resident Geologist office):
52L07NE E-2 (B-1), F-4 and N-2.
ASSAYS:
Sample No.
Rock Name
Au
ppb
Ag
ppm
Pd
ppb
Pt
ppb
Cr
ppm
Co
ppm
Ni
ppm
Cu
ppm
Mo
ppm
Pb
ppm
Zn
ppm
94JRP1006
opx-crd-grt
rock
**
2.4
**
**
**
27.55
91
< 100
<8
**
42.82
94JRP1052
bt-opx-crd
rock
<3
<2
<5
< 10
200
29.33
103
< 100
<8
<7
47.54
bt – biotite; crd – cordierite; grt – garnet; opx – orthopyroxene
124
18. DEPOSIT NAME: LOWER FORTUNE LAKE OCCURRENCE (STRATMAT
OCCURRENCE)
COMMODITIES: Cu
UTM COORDINATES: 374880.0 mE, 5590201.0 mN
UTM Datum: NAD27
MDI No.: MDI52L07NW00034
Mining Division: Kenora
Area Name: Werner Lake
UTM ZONE: 15
Claim Map No.: G-2654
LOCATION AND ACCESS:
The occurrence is located on Lower Fortune Lake which is only accessible by floatplane. Several minor chalcopyrite occurrences are located in outcrop exposures along the extreme south shore of the lake. The actual
Stratmat occurrence is located about 150 m south of the lake, unfortunately, the author was unable to locate the
trenches.
EXPLORATION HISTORY:
1956: Stratmat Limited sunk a test pit and diamond drilled 3 holes totalling 502 feet at the occurrence. Copper values ranging from 0.09% to 2.60% Cu were reported from drill core as well as some low silver values.
1957: Sogemines Development Co. Ltd. conducted geological mapping and diamond drilled 5 holes totalling
485 feet on the south shore of Lower Fortune Lake which was part of their “Grant claim group”.
1962-- 1963: Nickel Mining and Smelting Corp. optioned the property and conducted geological mapping,
sampling and diamond drilling. Drilling was conducted along the west shore of Lower Fortune Lake and in the
vicinity of the Sogemines diamond-drill holes. Three holes totalling 1323 feet were completed and intersected
a “biotite-tremolite-magnetite rock” and disseminated chalcopyrite in biotite-garnet gneiss and granite pegmatite.
1995: Staked by Canmine Resources Corporation.
GEOLOGICAL DESCRIPTION:
Province: Superior
Subprovince: English River
Metamorphism: 1) Type: Regional
2) Grade: Granulite
Assemblage: English River
The Stratmat occurrence is located about 200 m south of an east-striking fault splay that extends from the
Werner-- Rex lakes fault at Werner Lake.
The Stratmat occurrence is situated within diatexite and peraluminous granitoid rocks that contain discontinuous pods and lenses of mafic gneiss and altered ultramafic and mafic intrusive rocks.
LITHOLOGIC DESCRIPTION:
The rocks at Lower Fortune Lake are strongly deformed and variably mylonitized. A strong foliation strikes
east-northeast and dips moderately to the north. Numerous Z-drag folds with east-striking axial planes have
shallow plunges to the east.
The majority of the rocks at Lower Fortune Lake consist of diatexite and peraluminous granitoid rocks with
variable (10 to 80%) amounts of garnet, cordierite and orthopyroxene porphyroblasts. Numerous discontinuous, relatively small, enclaves of strongly deformed and highly metamorphosed mafic gneiss, anorthosite, gabbro and amphibolitized ultramafic rocks are scattered throughout the migmatite. All of the rock types are intruded by late granitic pegmatite dikes. Carlson (1958) described the occurrence as a large inclusion of paragneiss enclosed within massive granite.
The mafic gneiss is commonly coarse-grained and garnetiferous (50% garnet) with large orthopyroxene porphyroblasts. Ultramafic rocks are fine- to medium-grained, dark green, amphibolitized and recrystallized.
Anorthosite is typically coarse-grained and very strongly deformed.
MINERAL DESCRIPTION:
Little information is available on this occurrence. Diamond-drill logs describe the mineralization as, “weak to
moderate, fine-grained, disseminated chalcopyrite and pyrrhotite”. Host rocks are described as a “grey gneiss”
which may or may not contain garnet and biotite and pink feldspar porphyry. Diamond drilling conducted by
Sogemines intersected narrow sections of heavy biotite-garnet with finely disseminated chalcopyrite. Some
disseminated magnetite was also noted in drill core.
125
Chalcopyrite occurrences are exposed in outcrops on the south shore of Lower Fortune Lake. These occurrences consist of 1 to 15% disseminated chalcopyrite and minor molybdenite in mafic gneiss; biotite-garnet
schist; ultramafic rocks; and biotitic and garnetiferous migmatite. The chalcopyrite also occurs as coarse aggregates in small biotite-garnet patches in diatexite and in narrow (1 cm) sulphide veins. Minor molybdenite
occurs in an amphibolitized ultramafic rock adjacent to a pegmatite dike.
ALTERATION DESCRIPTION:
Minor chloritic alteration of mafic minerals adjacent to chalcopyrite mineralization.
MINERALIZED ZONE:
Strike: 2500 Dip: 650 Shape: Irregular Character: Disseminated, veins
Classification: Hydrothermal, remobilized
ASSESSMENT FILES (Kenora Resident Geologist office):
52L07NW I-2, L-3, U-1.
ASSAYS:
Cu
(ppm)
Ni
Co
Cr
Mo
(ppm) (ppm) (ppm) (ppm)
Au
(ppb)
Ag
(ppm)
12.2
326
7.7
175
<8
29
2
126
95
<8
50
4
< 40
72
84
144
84
5
< 40
58.5
42
14
514
10.6
Sample No.
Rock Name
94JRP–1173
granitic
leucosome
2.40%
< 40
60.7
9
94JRP-- 1174
granitic
leucosome
1185
< 40
34.5
94JRP-- 1175 mafic gneiss
2471
< 40
94JRP-- 1176 mafic gneiss
0.72%
94JRP-- 1177 mafic gneiss
3.20%
Samples were collected from outcrops on the south shore of Lower Fortune Lake.
126
19. DEPOSIT NAME: NORPAX OILS AND MINES LTD. PROSPECT
COMMODITIES: Ni, Cu, Cr, Pd, Pt
UTM COORDINATES: 356739.0 mE, 5592310.0 mN
UTM Datum: NAD27
MDI No.: MDI52L06NE00016
Mining Division: Kenora
Area Name: Reynar Lake
UTM ZONE: 15
Claim Map No.: G-2636
Mining Location: KRL 34766
LOCATION AND ACCESS:
The property is accessible from the Gordon Lake mine road. The shaft and rock dump is located on the south
shore of Almo (Tigar) Lake and is visible from the road. Walk approximately 60 m north of the road to the
shaft site.
EXPLORATION HISTORY:
1953: C. Alcock discovered and trenched three copper-nickel occurrences in mineralized ultramafic pods
along the south shore of Almo Lake. Selco Exploration Co. Ltd. conducted geophysical surveys and diamond
drilling.
1954-- 1957: Norpax Oils and Mines Ltd. acquired the property and conducted extensive diamond drilling followed by underground exploration and development. A 3-compartment vertical shaft was sunk to 402 feet
with drifting conducted on 2 levels established at the 250- and 375-foot levels. A narrow zone of sulphide
mineralization was delineated by diamond drilling along a strike length of 1400 feet. The company changed
its name to Norpax Nickel Mines Ltd. in 1957 and operations were suspended.
1962: Optioned to Nickel Mining and Smelting Corp. who dewatered the workings and conducted underground sampling.
1970: Optioned to Consolidated Manitoba Mines Ltd. who conducted ground geophysical surveys and geological mapping.
1977: Two diamond-drill holes totalling 1766 feet were completed by Prestige Mines Ltd.
1988: A 194-foot diamond-drill hole was completed on the property by Ferguson Mining Services.
GEOLOGICAL DESCRIPTION:
Province: Superior
Subprovince: English River
Metamorphism: 1) Type: Regional
2) Grade: Amphibolite
Assemblage: English River
The prospect is situated along the east-striking, steeply north-dipping Werner-- Rex lakes fault that extends
along the contact between metasedimentary migmatite to the north and tonalitic rocks of the Marijane batholith to the south. The fault strikes east across the Manitoba-- Ontario provincial boundary through Reynar,
Almo, Gordon, Werner and Rex lakes to Bug Lake and beyond for a strike length of about 32 km. The fault
bifurcates into several fault splays at the east end of Werner Lake and the east end of Reynar Lake. Overall
horizontal displacement along the fault is interpreted to be dextral. The Werner-- Rex lakes fault is intersected
by a northeast-striking crossfault in the vicinity of the Norpax property.
Deformed, metamorphosed and metasomatized gabbro, leucogabbro, anorthosite and ultramafic pods are situated within and adjacent to the Werner-- Rex lakes fault and may have originally been part of one stratiform,
layered intrusion. The ultramafic pods are relatively small, amphibolitized and recrystallized and host oxide
and sulphide minerals such as magnetite, chromite, pyrrhotite and chalcopyrite. The footwall of the fault consists of mylonitized tonalite-granodiorite while the hanging wall consists of diatexite with abundant garnet porphyroblasts and tectonic inclusions of gabbro and ultramafic rock.
LITHOLOGIC DESCRIPTION:
The dominant lithologies at the Norpax prospect are ultramafic rocks hosting variable amounts of sulphide
mineralization; tonalite-granodiorite; migmatite and gabbro. Diamond drilling intersected pegmatite, biotite
gneiss, biotite-amphibole schist and peridotite.
Pieces of ultramafic rock can be found in the waste rock dump near the shaft. The rocks are dark green, massive, medium- to coarse-grained, amphibolitized and commonly biotitic. The ultramafic rock in diamond-drill
core is described as a peridotite with biotitic margins that may be garnetiferous. The peridotite is also interlayered with biotite-plagioclase layers and is reported to be enclosed within a biotite-amphibole-plagioclase schist
or gneiss.
127
The gabbro is medium-grained, recrystallized, amphibolitized, biotitic and very strongly foliated. Pieces of
gabbro at the rock dump commonly host small pegmatite veins composed of biotite, plagioclase, potassic feldspar and quartz.
The tonalite-granodiorite is medium-grained, relatively equigranular, pink-grey with diffuse pegmatitic or pink
granitic patches. The tonalite is very strongly foliated with narrow (< 20 cm) mylonite zones and a common
gneissic texture with mafic platy minerals segregated into layers. The tonalite commonly hosts small xenoliths
of gabbro and ultramafic rock and late pegmatite dikes.
The migmatite is a massive, medium- to coarse-grained, homogeneous diatexitic metasedimentary migmatite
consisting of pink-white weathering granitoid and pegmatoid material with less than 10% strongly foliated
wacke and pelitic paleosome. The migmatite may contain inclusions and lenses of amphibolitized gabbro.
MINERAL DESCRIPTION:
Sulphide minerals consist of chalcopyrite, pyrrhotite, pyrite, pentlandite and violarite. Disseminated magnetite
was also observed.
Sulphide mineralization consists of semi-massive to disseminated pyrrhotite, chalcopyrite and pyrite. The
semi-massive sulphide minerals have a well developed, strong, protomylonite or “ball-texture” consisting of
rounded fragments of wall rock (tonalite, pegmatite, ultramafic rock) embedded in fine-grained pyrrhotite.
This texture is indicative of faulting and solid state remobilization of the sulphide minerals. The sulphide minerals also appear to be remobilized and injected along fractures and thick veins. sulphide minerals are hosted
in strongly biotitic, amphibolitized, mafic and ultramafic rocks and late biotite-feldspar-quartz pegmatite
dikes. Sulphide mineralization intersected in diamond-drill core is described as 2 to 10% disseminated chalcopyrite and pyrrhotite in biotitic rocks and peridotite. Seams of pyrrhotite and pentlandite were noted in biotite
gneiss. Pegmatite dikes host disseminated chalcopyrite.
Underground development work indicated that the mineralization at the 250-foot level occurred within a
650-foot long zone with an average grade of 1.32% Ni and 0.85 % Cu across an average width of 11.8 feet.
The mineralized zone on the 375-foot level was 590 feet long with an average grade of 1.23% Ni and 0.99%
Cu across an average width of 26.5 feet. Grab samples from the waste rock dump have analyzed as high as
7000 ppb Pd and 210 ppb Pt (Blackburn et al. 1988).
ALTERATION DESCRIPTION:
Mafic and ultramafic rocks on the waste rock dump are strongly biotitic. Veins of biotite were noted in some
gabbroic rocks and large pieces composed entirely of large (< 4 cm) books of biotite are common. The biotitization is a result of recrystallization of serpentinized ultramafic rocks by a combination of metasomatic and
metamorphic reactions between the ultramafic-mafic rocks, felsic country rocks, pegmatites and peraluminous
intrusive rocks.
Diamond-drilling intersected variably hematized ultramafic rocks and strong hematization in the Werner-- Rex
lakes fault zone. Diamond-drill hole 2-77 (Assessment file 52L06NE R-- 1) intersected a granite breccia that
was recemented by hematite in the fault zone.
MINERALIZED ZONE:
Name: Norpax Length: 650 feet Thickness: up to 26.5 feet Strike: 2700 Dip: 800
Plunge: northwest Shape: Sheet or tabular shape Structure: Breccia, Fault Character: Tabular
Classification: Magmatic, remobilized
RESERVES:
COMMODITY
GRADE
TONNAGE
CATEGORY
Nickel
Copper
1.2%
0.5%
1 010 000 tons
Probable
Probable
SOURCE: Canadian Mines Handbook, 1963, p.215 (Norpax Nickel Mines Ltd.)
ASSESSMENT FILES (Kenora Resident Geologist office):
52L06NE K-2; K-3; N-1; R-1; T-1 and 52L07NW E-2 (A-3).
128
ASSAYS:
Sample No.
Rock Name
Au
(ppb)
Ag
(ppm)
Pd
(ppb)
Pt
(ppb)
Cr
(ppm)
Co
(ppm)
Ni
(ppm)
Cu
(ppm)
Zn
(ppm)
94JRP1067
bt-rich u/m
rock
<3
4
22
< 10
> 3000
125.2
2100
309
232.8
94JRP1068
gabbro
**
3.5
**
**
**
50.36
113
135
43.09
94JRP1069
u/m rock
12
3
249
81
3636
124.6
2565
1290
66.22
u/m - ultramafic
All samples were collected by the author from the waste rock dump.
Grab samples collected from rock dump material on the Norpax property by J.D. McCannell (Consultant Geologist, Norpax Oils and Mines Ltd.) analyzed 210 ppb Pt and 7000 ppb Pd (Blackburn et al. 1988).
Sample 94JRP1069 also analyzed 0.49% Cr2O3.
129
20. DEPOSIT NAME: QUEBEC NICKEL CORP. LTD. OCCURRENCE
COMMODITIES: Cu
UTM COORDINATES: 357817.0 mE, 5593491.0 mN
UTM Datum: NAD27
MDI No.: MDI52L06NE00023
Mining Division: Kenora
Area Name: Reynar Lake
and 33284
UTM ZONE: 15
Claim Map No.: G-2636
Mining Locations: KRL 33283
LOCATION AND ACCESS:
The occurrence is accessible from the Gordon Lake mine road. Launch a canoe on Almo Lake and paddle to
the north shore. Traverse north for approximately 1 km to the property. The occurrence is on the south shore
of an arcuate, unnamed lake. The trenches were not located, however, the author found broken rock pieces
containing abundant chalcopyrite, pyrite and pyrrhotite on the southeast shore of the lake at the mouth of a
small creek. A map in the Kenora assessment files (Assessment files 52L 6NE G-1 and Q-1) indicates that
Trench 1 is on the immediate shore of the lake near the creek and may have been below water at the time of
the property visit.
EXPLORATION HISTORY:
1954: Quebec Nickel Corp. Ltd. sunk 8 trenches and diamond drilled 8 holes totalling 486 feet. The holes
intersected disseminated pyrite in “banded, biotitic paragneiss” and pegmatite. The exploration work was conducted on claims KRL 33282 to 33285 inclusive, which were part of the company’s Wilson Lake claim group.
1956: Eastern Mining and Smelting Ltd. diamond drilled 11 holes totalling 5653 feet. Several holes intersected disseminated chalcopyrite, pyrite, pyrrhotite and molybdenite in biotitic, garnetiferous schists and
gneisses.
GEOLOGICAL DESCRIPTION:
Province: Superior
Subprovince: English River
Assemblage: English River
Metamorphism: 1) Type: Regional
2) Grade: Upper amphibolite to granulite
The Quebec Nickel Corp. Ltd. occurrence is located in the vicinity of a southeast-striking and vertical- to
north-dipping fault. The fault bifurcates a metasedimentary migmatite assemblage intruded by peraluminous
granitoid rocks and late-tectonic granite-granodiorite intrusions. The fault strikes southeast and is interpreted
to be the same fault that extends through the Werner Lake cobalt mine area (Carlson 1958).
Rocks that occur at the Quebec Nickel occurrence are very similar to the amphibolitized gabbro and mafic
gneiss at Rex, Werner and Almo lakes. These rocks occur as large lenses or pods (tectonic inclusions) in garnetiferous metatexite intruded by massive granite-granodiorite with diffuse pegmatitic phases.
LITHOLOGIC DESCRIPTION:
Mafic gneiss/gabbro: The mafic gneiss/gabbro is strongly foliated, fine- to coarse-grained and composed of
hornblende-biotite-plagioclase and magnetite with abundant black orthopyroxene and red garnet porphyroblasts. The rock has a typical rusty weathered surface and is interlayered with quartz-feldspar pegmatite and
minor leucosome. The gneiss contains small pods (1 x 3 cm) of coarse, dark green amphibole.
Granite-granodiorite: Massive, medium- to coarse-grained but relatively equigranular, buff grey to pink
weathering rock with diffuse pegmatitic phases. May contain xenoliths of mafic gneiss and gabbro. Intrudes
mafic gneiss and migmatite.
Migmatite: Consists of 40 to 90% moderately to strongly foliated wacke and pelitic paleosome (quartz-plagioclase-biotite-garnet) interlayered with medium- to coarse-grained granitoid and pegmatoid leucosome. Commonly hosts tectonic inclusions of mafic gneiss.
MINERAL DESCRIPTION:
Sulphide minerals consist of chalcopyrite, pyrite, pyrrhotite and molybdenite.
Little information is available on this occurrence. Diamond-drill logs describe the mineralization as disseminated or on fractures. Host rocks are described as a “paragneiss” which may or may not contain garnet and
biotite.
ALTERATION DESCRIPTION:
No information available.
130
ASSESSMENT FILES (Kenora Resident Geologist office):
52L06NE G-1 and Q-1.
ASSAYS:
Sample No.
Rock Name
94JRP1063 mafic gneiss
Au
(ppb)
Ag
(ppm)
Pd
(ppb)
Pt
(ppb)
Cr
(ppm)
Co
(ppm)
Ni
(ppm)
Cu
(ppm)
Zn
(ppm)
<3
2.8
<5
< 10
124
14.77
< 40
137
65.2
u/m - ultramafic
131
21. DEPOSIT NAME: QUEBEC NICKEL CORP. LTD. BEAVERHOUSE LAKE
OCCURRENCE
COMMODITIES: Cu
MDI No.: 52L07NW
Name: Werner Lake
Claim Map No.: G-2654
Mining Division: Kenora Area
LOCATION AND ACCESS:
The occurrence was not visited by the author. It is located about 500 m east-northeast of Beaverhouse Lake
which is northeast of Werner Lake.
EXPLORATION HISTORY:
1955: Quebec Nickel Corp. Ltd. conducted trenching and diamond drilled 9 holes totalling 307 feet. The
holes intersected disseminated chalcopyrite in “sheared dark gneiss” and biotite schist.
1995: Staked by Canmine Resources Corporation.
GEOLOGICAL DESCRIPTION:
Province: Superior
Subprovince: English River
Assemblage: English River
Metamorphism: 1) Type: Regional
2) Grade: Upper amphibolite to granulite
The Beaverhouse Lake occurrence is hosted within the metasedimentary migmatite assemblage intruded by
peraluminous granitoid rocks; late-tectonic granite-granodiorite intrusions and pegmatite dikes. The occurrence is situated north of the Werner-- Rex lakes fault.
LITHOLOGIC DESCRIPTION:
Lithologies are described as pegmatite; paragneiss; sheared dark gneiss; biotite-garnet schist; and biotite schist.
MINERAL DESCRIPTION:
Little information is available on this occurrence. Diamond-drill logs describe the mineralization as abundant
disseminated chalcopyrite. Host rocks are “sheared dark gneiss”; biotite-garnet schist with abundant garnet;
and biotite schists.
ALTERATION DESCRIPTION:
No information available.
MINERALIZED ZONE:
Shape: Irregular Character: Disseminated
Classification: Hydrothermal, remobilized
ASSESSMENT FILES (Kenora Resident Geologist office):
52L07NW N-4.
132
22. DEPOSIT NAME: QUEBEC NICKEL CORP. LTD. – REX LAKE OCCURRENCE
COMMODITIES: Cu, Ni, Pd, Pt
UTM COORDINATES: 380137.0 mE, 5590000.0 mN
UTM Datum: NAD27
MDI No.: MDI52L07NE00022
Mining Division: Kenora
Area Name: Rex Lake
UTM ZONE: 15
Claim Map No.: G-2637
LOCATION AND ACCESS:
Rex Lake is only accessible by floatplane. The Quebec Nickel Corp. Ltd. Rex Lake occurrence consists of a
few trenches located on the north shore of the lake, unfortunately, the author was unable to locate them.
EXPLORATION HISTORY:
1948: Frederick Mining and Development Group made preliminary examinations of the Turcotte copper-nickel occurrences located on the north shore of Rex Lake.
1955: Quebec Nickel Corp. Ltd. diamond drilled 7 short holes at the occurrence. The holes intersected paragneiss, pegmatite and biotite-amphibole schists with narrow sections of disseminated and massive chalcopyrite
and pyrite.
1956: Eastern Mining and Smelting Corp. Ltd. diamond drilled several holes at the occurrence. The holes
were drilled to test the down-dip extension of nickel mineralization exposed in test pits.
1962: Falconbridge Nickel Ltd. conducted a geological reconnaissance of the Rex Lake area.
1987: Falconbridge Limited optioned a contiguous group of 9 mining claims from R. Fairservice and R.
Knappet and conducted geological mapping and sampling. The company diamond drilled 1 hole (FO-1) to a
depth of 149 m at the occurrence. The diamond-drill hole intersected 3 to 5% disseminated chalcopyrite and
pyrite in a garnet-biotite-plagioclase schist.
GEOLOGICAL DESCRIPTION:
Province: Superior
Subprovince: English River
Metamorphism: 1) Type: Regional
2) Grade: Granulite
Assemblage: English River
The Quebec Nickel Corp. Ltd. Rex Lake occurrence is located south of an east-northeast-striking fault splay
that extends along the north shore of Rex Lake. The fault splay may be the eastward continuation of the Werner-- Rex lakes fault that extends southeast from Werner Lake. A strong northeast-striking foliation occurs
throughout the area. Folding of the metasedimentary migmatite assemblage is best developed along the north
shore of Rex Lake where dominant, tight, S-style symmetric folds with east-northeast-striking axial planar foliations plunge moderately to the northeast and east-northeast. Many of these folds contain asymmetric, secondorder, parasitic folds along their limbs. An east-northeast-striking, vertical, S2 mineral foliation is axial planar
to folds at Rex Lake.
The Quebec Nickel Corp. Ltd. Rex Lake occurrence is situated within homogeneous and inhomogeneous diatexite and peraluminous granitoid rocks that contain discontinuous pods and lenses of mafic gneiss and altered
ultramafic and mafic intrusive rocks.
LITHOLOGIC DESCRIPTION:
Mafic gneiss: Strongly foliated, medium-grained, mafic gneiss composed of biotite, amphibole, plagioclase
and disseminated magnetite. The mafic gneiss has a characteristic orange-brown weathered surface and contains a few layers of dark amphibole and thin, discontinuous, folded, quartz seams. Intruded by narrow, Z-drag
folded, granitic pegmatite dikes. Foliated 2650 with a steep dip to the north.
Orthopyroxene-cordierite rock: A coarse orthopyroxene-cordierite rock with disseminated magnetite, minor
biotite and alternating garnet-rich and cordierite-rich layers. Garnet and orthopyroxene porphyroblasts are up
to 2.5 cm in size. Garnet and cordierite abundance commonly exceeds 80%.
Foliated 2550 with a steep dip to the north.
The orthopyroxene-cordierite-garnet rock is commonly interlayered with fine-grained mafic gneiss and intruded by pegmatitic peraluminous leucosome which also contains cordierite, garnet and orthopyroxene.
MINERAL DESCRIPTION:
The only mineralization observed in outcrop were small patches of 1 to 5% disseminated chalcopyrite and malachite staining in the orthopyroxene-cordierite-garnet rock. Diamond drilling conducted by Quebec Mining
133
intersected the following mineralized sections in paragneiss and biotite schist: 1.02% Cu across 78.5 feet in
DDH 33355-1; 0.225% Cu across 6 feet in DDH 33355-2; 0.47% Cu across 10.5 feet in DDH 33355-16; and
1.3% Cu across 1.5 feet in DDH 33355-17. Diamond drilling by Falconbridge Ltd. intersected about 3 to 5%
disseminated chalcopyrite and pyrite in (DDH FO-1) a biotite-amphibole-plagioclase gneiss. The diamonddrill hole also intersected narrow magnetite layers throughout the mafic gneiss.
ALTERATION DESCRIPTION:
Some weak chloritization and sericitization in the mafic gneiss. The orthopyroxene-cordierite-garnet rock may
be a highly altered, metasomatized and metamorphosed ultramafic rock. Epidote alteration of the mafic gneiss
was noted in diamond-drill core.
MINERALIZED ZONE:
Shape: Irregular Structure: Foliation Character: Disseminated, foliation, patchy
Classification: Magmatic, hydrothermal, remobilized
ASSESSMENT FILES (Kenora Resident Geologist office):
52L07NE C-3, F-4, R-1 and S-2.
ASSAYS:
Sample No.
Rock Name
Au
ppb
Ag
ppm
Pd
ppb
Pt
ppb
Cr
ppm
Co
ppm
Ni
ppm
Cu
ppm
Mo
Pb
ppm ppm
Zn
ppm
94JRP1007
bt-qtz-opx
gneiss
<3
3
<5
< 10
532
72.93
139
< 100
<8
<7
52.82
94JRP1053
bt-opx-crd
rock
54
4
1705
192
388
842.8 2.4% 0.89%
<8
<7
<2
94JRP1054
bt-opx-crd
rock
<3
3
<5
< 10
327
39.87
121
228
< 20
<7
< 50
94JRP1055
bt-opx rock
<3
3
<5
< 10
533
58.72
152
< 100
<8
<7
31.37
bt – biotite; crd – cordierite; opx – orthopyroxene; qtz – quartz
Sample 94JRP1054 also analyzed 0.04% Cr2O3.
134
23. DEPOSIT NAME: RADIOACTIVE MINERALS LTD. – REX LAKE OCCURRENCE
COMMODITIES: Cu, Cr, Ni, Mo
UTM COORDINATES: 379661.0 mE, 5589750.0 mN
UTM Datum: NAD27
MDI No.: MDI52L07NE00026
Mining Division: Kenora
Area Name: Rex Lake
UTM ZONE: 15
Claim Map No.: G-2637
LOCATION AND ACCESS:
Rex Lake is only accessible by floatplane. The Rex Lake occurrence consists of at least 6 trenches located on
the north shore of the lake. The trenches are visible from the lake.
EXPLORATION HISTORY:
1948: Frederick Mining and Development Group made preliminary examinations of the Turcotte copper-nickel occurrences located on the north shore of Rex Lake.
1955: Quebec Nickel Corp. Ltd. diamond drilled 14 short holes at the occurrence. The holes intersected paragneiss, pegmatite and biotite-amphibole schists with narrow sections of disseminated and massive chalcopyrite and pyrite.
1962: Falconbridge Nickel Ltd. conducted a geological reconnaissance of the Rex Lake area.
1969: Duvan Copper Company Ltd. conducted geological mapping, trenching and sampling over a contiguous
group of 69 mining claims at the northeast end of Rex Lake. The claim group encompassed the trenches at the
Rex Lake occurrence.
1987: Falconbridge Limited optioned a contiguous group of 9 mining claims from R. Fairservice and R.
Knappet and conducted geological mapping and sampling. The company diamond drilled 2 holes (FO-2 and
FO-4), totalling 314.6 m, at the Rex Lake occurrence.
GEOLOGICAL DESCRIPTION:
Province: Superior
Subprovince: English River
Metamorphism: 1) Type: Regional
2) Grade: Granulite
Assemblage: English River
The Rex Lake occurrence is located south of an east-northeast-striking fault splay that extends along the north
shore of Rex Lake. The fault splay may be the eastward continuation of the Werner-- Rex lakes fault that extends southeast from Werner Lake. A strong northeast-striking foliation occurs throughout the area. Folding
of the metasedimentary migmatite assemblage is best developed along the north shore of Rex Lake where
dominant, tight, S-style symmetric folds with east-northeast-striking axial planar foliations plunge moderately
to the northeast and east-northeast. Many of these folds contain asymmetric, second-order, parasitic folds
along their limbs. An east-northeast-striking, vertical, S2 mineral foliation is axial planar to folds at Rex Lake.
The Rex Lake occurrence is situated within homogeneous and inhomogeneous diatexite and peraluminous
granitoid rocks that contain discontinuous pods and lenses of mafic gneiss and altered ultramafic and mafic
intrusive rocks.
LITHOLOGIC DESCRIPTION:
East Trenches
Leucogabbro/anorthosite: Coarse-grained, strongly foliated and composed of recrystallized white plagioclase
with interstitial mafic minerals such as amphibole and pyroxene. Strong foliation strikes between 500 and 670
with moderate dips to the north and south. A strong mineral lineation trends 520 to 670 and plunges moderately to the east. The leucogabbro is variably epidotized and intruded by granitic pegmatite dikes. Coarse biotite
is concentrated on foliation planes and fractures. An outcrop of foliated leucogabbro, on the north shore of
Rex Lake, contains narrow bands or layers of coarse-grained, dark green-black amphibole and magnetite.
These ultramafic layers may represent original cumulate layers of pyroxene within the leucogabbro.
Ultramafic rock: Medium-grained, equigranular, black to dark green, recrystallized and composed of orthopyroxene, amphibole and hercynite with 15 to 80% magnetite. Very strongly foliated and rusty with coarse biotite on foliation surfaces. Intruded by narrow veinlets and dikes of granitic pegmatite. The ultramafic rock
intersected in DDH FO-4 is massive, medium-grained, magnetic, hematized and interlayered with narrow
bands of biotite-plagioclase schist.
Gabbro: Medium-grained, strongly foliated, dark grey-green, recrystallized and composed of amphibole, plagioclase, 5 to 15 % orthopyroxene and 25 to 80% magnetite. Gabbro intersected in DDH FO-4 is strongly
135
brecciated; intruded by granitic pegmatite; epidotized; and commonly hosts 1 to 5 cm thick magnetite layers
with some layers up to 100 cm thick.
Granitic pegmatite: Massive, medium-grained and equigranular with diffuse pegmatitic phases. Composed of
pink and white feldspar, quartz and minor mafic minerals (biotite, amphibole). Large (2 m x 1.5 m) foliated
and folded enclaves of leucogabbro occur within the north margin of the Gone Lake pluton.
West Trenches
Same rock types as in the East trenches except that the anorthositic gabbro is very coarse-grained and less altered. The gabbro contains coarse, diffuse, pegmatitic patches composed of plagioclase, orthopyroxene, clinopyroxene and some biotite. The patches are rimmed with black amphibole selvages. The ultramafic rock is
strongly biotitic.
A leucocratic, fine- to medium-grained, equigranular and “sugary-textured” leucocratic gabbro contains disseminated aggregates of black amphibole and magnetite in a groundmass of white plagioclase, orthopyroxene
and clinopyroxene.
MINERAL DESCRIPTION:
The ultramafic rock is mineralized with 10 to 20% combined pyrite and chalcopyrite (py > cp) on fractures and
foliation surfaces. Pyrite and chalcopyrite are also disseminated and interstitial to silicate minerals. Minor,
medium-grained, disseminated molybdenite (1 to 3%) occurs on fractures and as small aggregates combined
with pyrite in narrow biotitic shears. Magnetite is disseminated throughout the ultramafic rock and gabbro but
also occurs in layers and irregular aggregates. The ultramafic rock also hosts a massive chromite layer intersected in diamond drilling (DDH FO-4). The ultramafic rock is mineralized with 3% disseminated chalcopyrite and pyrite in diamond-drill hole FO-4 which intersected 1.17% Cu across 29.5 m.
Ball textured and brecciated massive sulphides were observed in a 5 cm wide sulphide vein. The ball texture
consists of rounded fragments of silicate minerals and wall rock in a pyritic groundmass. This texture is indicative of sulphide mineral remobilization.
The anorthositic gabbro is weakly mineralized with disseminated chalcopyrite in the West trenches.
ALTERATION DESCRIPTION:
The ultramafic and mafic intrusive rocks are strongly chloritized adjacent to sulphide mineralization and variably biotitic and epidotized adjacent to granitic pegmatite dikes. The ultramafic rock was serpentinized metamorphosed and metasomatized. Strongly foliated and sheared anorthositic gabbro is chloritic and sericitized.
The epidotized anorthosite contains pale green saussuratized plagioclase.
An outcrop of leucogabbro, west of the trenches, contains a metamorphosed alteration assemblage that consists
of abundant (70%) disseminated cordierite porphyroblasts (< 2 cm in size) and 5% fine-grained garnet porphyroblasts that replace previously altered feldspar. Abundant biotite and accessory hercynite accompany the cordierite-garnet assemblage. The alteration is situated at a contact between the leucogabbro and peraluminous
diatexite.
DDH FO-4 intersected strong hematite alteration in ultramafic rocks with disseminated specular hematite and
patches and seams of hematite. Strong epidote alteration was also intersected in the diamond-drill hole.
MINERALIZED ZONE:
Shape: Irregular Structure: Fractures, foliations, shears, layers Character: Disseminated, foliation and
fracture parallel Classification: Magmatic, hydrothermal, remobilized
ASSESSMENT FILES (Kenora Resident Geologist office):
52L07NE B-1, F-4, R-1, S-2, T-1; 52L07NW S-2
136
ASSAYS:
East Trenches
Sample No.
Rock
Name
Au
ppb
Ag
ppm
Pd
ppb
Pt
ppb
Cr
ppm
Co
ppm
Ni
ppm
Cu
ppm
Mo
ppm
Pb
ppm
Zn
ppm
94JRP1002
u/m
43
8.4
151
< 10
> 3000
103.7
159
4.40%
<8
15
230.9
94JRP1004
gabbro
37
5.3
30
< 10
348
706.1
940
0.62%
9.77
9
63.65
94JRP1016
l gabbro
83
5
<5
< 10
70
55.01
183
4764
28.19
7
62.61
94JRP1016A
l gabbro
13
3
<5
< 10
90
31.93
161
826
10.33
<7
122.5
94JRP1018
u/m
8
5.1
15
< 10
557
231.5
785
0.74%
<8
29
133.2
94JRP1019
u/m
<3
3
<5
< 10
1100
81.68
181
185
182.6
<7
165.1
94JRP1020
u/m
<3
3
74
55
> 1.5%
111.6
115
309
<8
7
225.4
94JRP1021
gabbro
<3
2
42
< 10
433
194.1
811
1300
<8
10
115.8
94JRP1022
gabbro
8
2
<5
< 10
394
150.4
652
1996
<8
7
105.7
94JRP1023
gabbro
17
6.4
115
< 10
266
761
2549
0.68%
<8
15
51.95
94JRP1024
u/m
<3
3
<5
< 10
6305
92.06
< 40
< 100
<8
<7
120.3
94JRP1025
gabbro
<3
2
<5
< 10
849
81.58
191
110
<8
<7
78.2
94JRP1034
u/m
<3
3
<5
< 10
396
104.2
164
277
<8
<7
104.8
l gabbro – leucogabbro; u/m ultramafic
137
West Trenches
Sample No.
Rock
Name
Au
ppb
Ag
ppm
Pd
ppb
Pt
ppb
Cr
ppm
Co
ppm
Ni
ppm
Cu
ppm
Mo
ppm
Pb
pp
m
Zn
ppm
94JRP1026
u/m
24
4
<5
< 10
221
65.59
64
701
49.92
<7
78.06
94JRP1026A
u/m
54
4
<5
< 10
232
61.73
115
4019
<8
<7
68.01
94JRP1027
gabbro
4
3
<5
< 10
237
67.7
159
439
<8
<7
89.16
94JR1028
l gabbro
25
7
6
< 10
546
39.88
99
2963
15.87
<7
43.62
94JRP1029
l gabbro
<3
3
<5
< 10
31
29.91
151
717
15.57
<7
29.72
94JRP1030
gabbro
<3
3
<5
< 10
200
63.38
105
345
9.76
<7
44.8
94JRP1031
gabbro
67
6
<5
< 10
140
60.48
< 40
8
73.19
94JRP1032
gabbro
5
4
<5
< 10
239
69.08
84
435
8.54
<7
49.52
94JRP1062
l gabbro
21
4
<5
< 10
429
52.62
138
3556
11.87
<7
56.25
l gabbro - leucogabbro
Sample 94JRP1028 also analyzed 0.07% Cr2O3.
138
0.66% 39.12
24. DEPOSIT NAME: REXORA No. 3 OCCURRENCE (VANDERBRINK SHOWING)
COMMODITIES: Ni, Cu, Cr, Pd, Pt
UTM COORDINATES: 364517.0 mE, 5591319.0 mN
UTM Datum: NAD27
MDI No.: MDI52L07NW00039
Mining Division: Kenora
Area Name: Werner Lake
UTM ZONE: 15
Claim Map No.: G-2654
Mining Location: KRL 30056
LOCATION AND ACCESS:
The occurrence is accessible from the Gordon Lake mine road. Follow the road southeast from Gordon Lake
on foot or by ATV for about 1 km. Traverse south from the road for 180 m to the low grassy area immediately
northwest of Small Lake. Cross the grassy area to the large rusty outcrop and trenches that should be clearly
visible. Walk northwest for about 90 m along the low outcrop ridge to find the other trenches. Two trenches
(12 m apart; 3 m long x 2 m wide) have been sunk on the peridotite that is most clearly visible (edge of the low
grassy area). One overgrown trench (3 m long) has been sunk on the peridotite that is northwest of the first 2
trenches.
EXPLORATION HISTORY:
1942: A. Vanderbrink and H. Byberg made several copper-nickel discoveries in and around the Gordon–Werner lakes area. Noranda Mines Ltd. conducted ground geophysical surveys, stripping, trenching and diamond
drilling on these properties.
1948: The area was restaked by Aero Prospecting Syndicate and acquired by Rexora Mining Corporation Ltd.
who conducted some diamond drilling. The property was optioned to Falconbridge Nickel Mines Ltd. who
conducted magnetic and electromagnetic ground geophysical surveys and over 10 000 feet of diamond drilling
in 1949.
1971: Consolidated Canadian Faraday Ltd. conducted ground geophysical surveys on the property and diamond drilled 2 holes totalling 1215 feet..
GEOLOGICAL DESCRIPTION:
Province: Superior
Subprovince: English River
Assemblage: English River
Metamorphism: 1) Type: Regional
2) Grade: Amphibolite
The Rexora No. 3 occurrence is situated on the Werner-- Rex lakes fault that extends along the contact between
a metasedimentary migmatite assemblage to the north and the tonalitic Marijane batholith. The fault strikes
east across the Manitoba-- Ontario provincial border through Reynar, Almo, Gordon, Werner and Rex lakes to
Bug Lake and beyond for a strike length of approximately 32 km. The fault bifurcates into several fault splays
at the east end of Werner Lake and the east end of Reynar Lake. Overall horizontal displacement along the
fault is interpreted to be dextral. The fault strikes southeast and dips north on the Rexora property. S- and Zdrag folds were observed in the migmatitic rocks north and northeast of the fault.
Deformed, metamorphosed and metasomatized gabbro, leucogabbro, anorthosite and ultramafic pods are situated within and adjacent to the Werner-- Rex lakes fault. The ultramafic-mafic rocks may have originally been
part of one stratiform, layered intrusion. The ultramafic pods are relatively small, amphibolitized and recrystallized and host oxide and sulphide minerals such as magnetite, chromite, pyrrhotite and chalcopyrite. The
Rexora No. 3 occurrence consists of a small ultramafic pod and associated gabbroic rocks located on the footwall of the Werner-- Rex lakes fault. The footwall also consists of mylonitized tonalite-granodiorite of the Marijane batholith while the hanging wall consists of metatexite intruded by late-tectonic pegmatite dikes.
LITHOLOGIC DESCRIPTION:
Ultramafic rocks: Rusty, non-descript, very black, fine- to coarse-grained ultramafic rocks are amphibolitized
and contain “patches” of fibrous green actinolite and coarse biotite. The rocks also contain discontinuous layers of up to 50–60% combined magnetite and chromite. In thin section the rock is recrystallized with a granoblastic polygonal texture and consists of colourless to pale green, weakly pleochroic, amphibole (actinolite-tremolite) and large patches of fine-grained matted fibers of antigorite and sinuous intersecting “veins” of serpentine. Minor green hercynite and altered olivine were also identified.
Tonalite-granodiorite: Medium-grained, pink-grey, weakly to strongly foliated, relatively equigranular but
may be megacrystic with plagioclase phenocrysts. Composed of white-pink feldspar, quartz, biotite and amphibole.
Migmatite: Metatexitic metasedimentary migmatite with 40-- 90% moderately to strongly foliated wacke and
pelitic paleosome interlayered with medium- to coarse-grained granitoid and pegmatoid leucosome. Commonly intruded by late-tectonic pegmatitic granitic dikes.
139
Gabbro: Fine- to medium-grained, homogeneous, amphibolitized gabbro (hornblende-biotite-plagioclase)
hosting biotite-rich pegmatite. The gabbro is variably porphyritic with <5% white feldspar phenocrysts up to 2
cm in size. The gabbro is foliated and located on the footwall side of the Werner-- Rex lakes fault and appears
to be distributed between the tonalite and the ultramafic pods.
MINERAL DESCRIPTION:
Sulphide minerals consist of pyrrhotite, chalcopyrite and minor pyrite. Oxide minerals consist of magnetite,
chromite and hercynite.
Pyrrhotite is the most abundant sulphide mineral ranging from 5-- 20%. It is commonly disseminated but also
occurs as massive, fine-grained aggregates or as large crystals up to 1 cm in size. The host rocks also contain
about 1-- 3% disseminated chalcopyrite and very minor pyrite.
Oxide minerals consist of magnetite and chromite, which are difficult to distinguish in hand specimen since
they occur together in thick, fine-grained, massive, irregular aggregates and layers. Coarse-grained (1 cm)
magnetite was observed in one of the trenches.
The Rexora No. 3 occurrence consists of 2 separate zones: Zone A and Zone B. Trenching and stripping conducted by Rexora Mining revealed that Zone A is about 7.6 m long and 7.6 m wide while Zone B is 18 m long
and 9 m wide. Zone B is described as the best mineralized zone with 10 to 15% combined sulphide minerals
(Assessment file 52L07NW S–2).
ALTERATION DESCRIPTION:
The primary mineralogy of the ultramafic rocks has been replaced by a prograde metamorphic mineral assemblage of actinolite-tremolite and hercynite with retrograde alteration of amphibole to antigorite.
The ultramafic rocks also contain abundant coarse biotite which is a result of recrystallization of serpentinized
ultramafic rocks by a combination of metasomatic and metamorphic reactions between the ultramafic/mafic
rocks, felsic country rocks, pegmatites and peraluminous intrusive rocks.
MINERALIZED ZONE:
Name: No.3 zone Length: 25.6 m Thickness: 7 - 9 m Strike: 2900 Dip: 800
Shape: Irregular Structure: Fault Character: Podiform
Classification: Magmatic
ASSESSMENT FILES (Kenora Resident Geologist office):
52L07NW E-2 (A-1, A-4, B-1), S-2.
ASSAYS:
Sample No.
Rock
Name
Au
(ppb)
Ag
Pd
(ppm) (ppb)
Pt
(ppb)
Cr
(ppm)
94JRP1108
u/m rock
25
3
94JRP1109
u/m rock
30
94JRP1110*
u/m rock
23
Co
Ni
Cu
Zn
(ppm) (ppm) (ppm) (ppm)
746
106
4094
232
0.67% 0.57%
55.1
2
765
159
6745
199
0.58%
102
3
902
425
>15000
177
0.35% 0.74%
2383
278
u/m - ultramafic
* - 94JRP1110 was collected from the west trench.
Grab samples collected from the showing, by Blackburn and Vogg (Blackburn et al. 1988) analyzed up to 210
ppb Pt and 800 ppb Pd. Sample 94JRP1107 was collected from the west trench for whole rock geochemistry
and analyzed 0.85% Cr2O3.
140
25. DEPOSIT NAME: REXORA No. 4 OCCURRENCE (SMALL LAKE OCCURRENCE)
COMMODITIES: Ni, Cu, Cr, Pd, Pt
UTM COORDINATES: 365198.0 mE, 5590967.0 mN
UTM Datum: NAD27
MDI No.: MDI52L07NW00040
Mining Division: Kenora Area Name: Werner Lake
UTM ZONE: 15
Claim Map No.: G-2654
Mining Location: KRL 30057
LOCATION AND ACCESS:
The occurrence is accessible from the Gordon Lake mine road. Follow the road southeast from Gordon Lake
on foot or by ATV for about 1km. Traverse south from the road for 213 m to the small pond about 150 m
southeast of Small Lake. Two trenches, trenches 2.4 m long and 1.2 m wide, are located on the north side of a
beaver dam. The first trench, closest to the beaver dam, has been sunk on amphibolitized peridotite. The second trench is sunk on metasedimentary migmatite interlayered with granitic pegmatite and some narrow layers
of gabbro. No sulphide minerals or ultramafic rock were observed in the second trench.
EXPLORATION HISTORY:
1942: A. Vanderbrink and H. Byberg made several copper-nickel discoveries in and around the Gordon-- Werner lakes area. Noranda Mines Ltd. conducted ground geophysical surveys, stripping, trenching and diamond
drilling on these properties.
1948: The area was restaked by Aero Prospecting Syndicate and acquired by Rexora Mining Corporation Ltd.
who conducted some diamond drilling. The property was optioned to Falconbridge Nickel Mines Ltd. who
conducted magnetic and electromagnetic ground geophysical surveys and over 10 000 feet of diamond drilling
in 1949.
GEOLOGICAL DESCRIPTION:
Province: Superior
Subprovince: English River
Metamorphism: 1) Type: Regional
2) Grade: Amphibolite
Assemblage: English River
The Rexora No. 4 occurrence is situated on the Werner-- Rex lakes fault that extends along the contact between
a metasedimentary migmatite assemblage to the north and the tonalitic Marijane batholith. The fault strikes
east across the Manitoba-- Ontario provincial border through Reynar, Almo, Gordon, Werner and Rex lakes to
Bug Lake and beyond for a strike length of approximately 32 km. The fault bifurcates into several fault splays
at the east end of Werner Lake and the east end of Reynar Lake. Overall horizontal displacement along the
fault is interpreted to be dextral. The fault strikes southeast and dips north on the Rexora property. S- and Zdrag folds were observed in the migmatitic rocks north and northeast of the fault.
Deformed, metamorphosed and metasomatized gabbro, leucogabbro, anorthosite and ultramafic pods are situated within and adjacent to the Werner-- Rex lakes fault. The ultramafic-mafic rocks may have originally been
part of one stratiform, layered intrusion. The ultramafic pods are relatively small, amphibolitized and recrystallized and host oxide and sulphide minerals such as magnetite, chromite, pyrrhotite and chalcopyrite. The
Rexora No. 4 occurrence consists of a small ultramafic pod and associated gabbroic rocks located in the footwall of the Werner-- Rex lakes fault. The footwall also consists of mylonitized tonalite-granodiorite of the Marijane batholith while the hanging wall consists of metatexite intruded by late-tectonic pegmatite dikes. The
metatexite contains up to 10% garnet porphyroblasts.
LITHOLOGIC DESCRIPTION:
Ultramafic rocks: Rusty, non-descript, very black, fine- to coarse-grained ultramafic rocks are amphibolitized
and contain “patches” of fibrous green actinolite and coarse biotite. The rocks also contain discontinuous layers of up to 80% combined magnetite and chromite. In thin section the rock is recrystallized with a granoblastic polygonal texture and consists of colourless to pale green, weakly pleochroic, amphibole (actinolite-tremolite) and large patches of fine-grained matted fibres of antigorite and sinuous intersecting “veins” of serpentine.
Tonalite-granodiorite: Medium-grained, pink-grey, weakly to strongly foliated, relatively equigranular but
may be megacrystic with plagioclase phenocrysts. Composed of white-pink feldspar, quartz, biotite and amphibole.
Migmatite: Metatexitic metasedimentary migmatite with 40-- 90% moderately to strongly foliated wacke and
pelitic paleosome interlayered with medium- to coarse-grained granitoid and pegmatoid leucosome. Commonly intruded by late-tectonic pegmatitic granitic dikes. The migmatite contains up to 10% garnet porphyroblasts.
141
MINERAL DESCRIPTION:
Sulphide minerals consist of pyrrhotite and chalcopyrite. Oxide minerals consist of magnetite and chromite.
Ultramafic rocks host layers and irregular aggregates of up to 80% combined massive magnetite and chromite.
Sulphide minerals consist of about 3% disseminated pyrrhotite and 1-2% chalcopyrite.
ALTERATION DESCRIPTION:
The primary mineralogy of the ultramafic rocks has been replaced by a prograde metamorphic mineral assemblage of actinolite-tremolite and hercynite with retrograde alteration of amphibole to antigorite.
The ultramafic rocks also contain abundant coarse biotite which is a result of recrystallization of serpentinized
ultramafic rocks by a combination of metasomatic and metamorphic reactions between the ultramafic/mafic
rocks, felsic country rocks, pegmatites and peraluminous intrusive rocks.
MINERALIZED ZONE:
Name: No. 4 zone Length: 6.0 m Thickness: 1.8 m Strike: 2950 Dip: 800
Shape: Irregular Structure: Fault Character: Podiform
Classification: Magmatic
ASSESSMENT FILES (Kenora Resident Geologist office):
52L07NW E-2 (B-1), S-1.
ASSAYS:
Sample No.
Rock
Name
Au
Ag
Pd
(ppb) (ppm) (ppb)
Pt
(ppb)
Cr
(ppm)
Co
Ni
Cu
Zn
(ppm) (ppm) (ppm) (ppm)
94JRP1113 u/m rock
36
3
411
94
>15000
191
0.32%
3225
213
94JRP1116 u/m rock
10
2
195
65
>15000
171
0.28%
1062
201
u/m - ultramafic
Grab samples collected from the showing, by Blackburn and Vogg (Blackburn et al. 1988) analyzed up to 135
ppb Pt and 510 ppb Pd. Sample 94JRP1113 was collected for geochemistry and analyzed 1.56% Cr2O3
142
26. DEPOSIT NAME: REXORA No. 5 PROSPECT (JEADLE No. 3 OCCURRENCE)
COMMODITIES: Ni, Cu, Cr, Pd, Pt
UTM COORDINATES: 367194.0 mE, 5590461.0 mN
UTM Datum: NAD27
MDI No.: MDI52L07NW00041
Mining Division: Kenora
Area Name: Werner Lake
and 19110
UTM ZONE: 15
Claim Map No.: G-2654
Mining Locations: KRL 19109
LOCATION AND ACCESS:
The occurrence is accessible from Werner Lake. Drive down the Gordon Lake mine road to the north shore of
Werner Lake. Launch a canoe at the large culvert. Paddle east along the north shore of the lake to a location
just west of Upper Falls creek. Two overgrown trenches are located about 20 m from the lakeshore. The west
trench is about 8 m long and 1.2 m wide. The east trenches consist of 2 trenches about 6 m apart and 5 m long
x 1.2 m wide.
EXPLORATION HISTORY:
1942: A. Vanderbrink and H. Byberg made several copper-nickel discoveries in and around the Gordon-- Werner lakes area. Noranda Mines Ltd. conducted ground geophysical surveys, stripping, trenching and diamond
drilling on these properties.
1948: The area was restaked by Aero Prospecting Syndicate and acquired by Rexora Mining Corporation Ltd.
who conducted some diamond drilling. The property was optioned to Falconbridge Nickel Mines Ltd. who
conducted magnetic and electromagnetic ground geophysical surveys and over 10 000 feet of diamond drilling
in 1949.
1952: The property was diamond drilled by Quebec Nickel Corporation Ltd.
1971: Consolidated Canadian Faraday Ltd. conducted ground geophysical surveys.
GEOLOGICAL DESCRIPTION:
Province: Superior
Subprovince: English River
Metamorphism: 1) Type: Regional
2) Grade: Amphibolite
Assemblage: English River
The Rexora No. 5 occurrence is situated on the Werner-- Rex lakes fault that extends along the contact between
a metasedimentary migmatite assemblage to the north and the tonalitic Marijane batholith. The fault strikes
east across the Manitoba-- Ontario provincial border through Reynar, Almo, Gordon, Werner and Rex lakes to
Bug Lake and beyond for a strike length of approximately 32 km. The fault bifurcates into several fault splays
at the east end of Werner Lake and the east end of Reynar Lake. Overall horizontal displacement along the
fault is interpreted to be dextral. The fault strikes east and dips north on the Rexora property.
Deformed, metamorphosed and metasomatized gabbro, leucogabbro, anorthosite and ultramafic pods are situated within and adjacent to the Werner-- Rex lakes fault. The ultramafic-mafic rocks may have originally been
part of one stratiform, layered intrusion. The ultramafic pods are relatively small, amphibolitized and recrystallized and host oxide and sulphide minerals such as magnetite, chromite, pyrrhotite and chalcopyrite. The
Rexora No. 5 occurrence consists of a small ultramafic pod and associated gabbroic rocks located immediately
north of the Werner-- Rex lakes fault.
LITHOLOGIC DESCRIPTION:
Ultramafic rocks: Dark green-grey to black, fine- to medium-grained, amphibolitized and serpentinized ultramafic rocks contain “patches” of fibrous green actinolite and coarse biotite. Pieces of coarse biotite-chlorite
schist are visible in the rock piles beside the trenches. The rocks contain disseminations and irregular aggregates of up to 80% combined magnetite and chromite. Magnetite also occurs along narrow (< 4 mm) fractures. In thin section the rock is recrystallized with a granoblastic polygonal texture and consists of colourless
to pale green, weakly pleochroic, amphibole (actinolite-tremolite) and large patches of fine-grained matted
fibers of antigorite and sinuous intersecting “veins” of serpentine.
Gabbro: The ultramafic rocks appear to be enclosed within a strongly deformed and amphibolitized, mediumgrained gabbroic rock interlayered with foliation parallel pink, granitic pegmatite. The rocks are strongly foliated 2700/900.
MINERAL DESCRIPTION:
Ultramafic rocks host disseminations and irregular aggregates of up to 80% combined massive magnetite and
chromite. Sulphide minerals consist of about 5% disseminated pyrrhotite; 3% disseminated pyrite; and less
143
than 2% chalcopyrite. Sulphide minerals are also concentrated along narrow fractures. The west trench hosts
the most abundant sulphide mineralization.
ALTERATION DESCRIPTION:
The primary mineralogy of the ultramafic rocks has been replaced by a prograde metamorphic mineral assemblage of actinolite-tremolite with retrograde alteration of amphibole to antigorite. The ultramafic rocks also
contain abundant coarse biotite which is a result of recrystallization of serpentinized ultramafic rocks by a
combination of metasomatic and metamorphic reactions between the ultramafic/mafic rocks, felsic country
rocks, pegmatites and peraluminous intrusive rocks.
MINERALIZED ZONE:
Name: No. 5 zone Length: 30.0 m Thickness: 15.2 m Depth: 22.9 m Strike: 2700 Dip: 800
Shape: Tabular Structure: Fault Character: Podiform
Classification: Magmatic
RESERVES:
COMMODITY
GRADE
TONNAGE
CATEGORY
Nickel
Copper
0.78%
0.42%
35 000 tons
Probable
Probable
SOURCE: Taylor 1950 ; Assessment file 52L07NW 0-1
ASSESSMENT FILES (Kenora Resident Geologist office):
52L07NW E-2 (A-1, B-1), N-1, S-1, 0-1.
ASSAYS:
Sample No.
Rock
Name
Au
(ppb)
Ag
Pd
(ppm) (ppb)
Pt
(ppb)
Cr
(ppm)
Co
Ni
Cu
Zn
(ppm) (ppm) (ppm) (ppm)
94JRP1124 u/m–west
trench
22
4
664
166
13975
248.5
0.6%
1493
69.62
94JRP1126
5
2
88
25
>15000
104
1124
2340
137
u/m–east
trench
u/m – ultramafic
Samples 94JRP1122, 1123, 1125, 1127 and 1128 were collected for whole rock geochemistry and analyzed
1.69% Cr2O3, 8.03% Cr2O3, 6.05% Cr2O3, 5.20% Cr2O3 and 1.17% Cr2O3, respectively.
144
27. DEPOSIT NAME: SOGEMINES No.1 OCCURRENCE (SHEARN CLAIM GROUP;
NORCO CLAIM GROUP 1)
COMMODITIES: Cu
UTM COORDINATES: 372841.0 mE, 5590760.0 mN
UTM Datum: NAD27
MDI No.: MDI52L07NW00049
Mining Division: Kenora
Area Name: Werner Lake
UTM ZONE: 15
Claim Map No.: G-2654
LOCATION AND ACCESS:
The property is located immediately west of Upper Fortune Lake. The trench is located about 300m west of
the northwest corner of the lake. The occurrence consists of 2 trenches on the top of a large outcrop ridge.
Only one of the trenches was located by the author.
EXPLORATION HISTORY:
1957: Sogemines Development Co. Ltd. conducted geological mapping and sampling over a large claim group
that encompassed most of the area around Upper Fortune Lake. The company referred to this part of the property as the “Shearn claim group”. Seven diamond-drill holes totalling 710.6 feet were drilled on the property.
Two of the holes were targeted on the trenches while the others were drilled south of the trenches. The diamond-drill holes intersected disseminated chalcopyrite in “biotite-hornblende gneiss” and garnetiferous
gneisses.
1962-- 1963: Nickel Mining and Smelting Corp. optioned the property and conducted airborne and ground geophysical surveys and some sampling. The property was referred to as the “Norco claim group 1”.
1987: Falconbridge Ltd. conducted some reconnaissance sampling west of Fortune Lake.
1995: Staked by Canmine Resources Corporation.
GEOLOGICAL DESCRIPTION:
Province: Superior
Subprovince: English River
Metamorphism: 1) Type: Regional
2) Grade: Granulite
Assemblage: English River
The Sogemines No.1 occurrence is located about 200 m north of an east-striking fault splay that extends from
the Werner-- Rex lakes fault at Werner Lake.
The Sogemines No.1 occurrence is situated within diatexite and peraluminous granitoid rocks that contain discontinuous pods and lenses of mafic gneiss, anorthosite, gabbro and altered ultramafic intrusive rocks.
LITHOLOGIC DESCRIPTION:
The rocks at Upper Fortune Lake are strongly deformed and variably mylonitized. A strong foliation strikes
east and dips moderately to the north. Numerous Z-drag folds with east-striking axial planes have shallow
plunges to the east.
The majority of the rocks at Upper Fortune Lake consist of diatexite and peraluminous granitoid rocks with
variable (10 to 95%) amounts of garnet, cordierite and orthopyroxene porphyroblasts. Numerous discontinuous, relatively small, enclaves of strongly deformed and highly metamorphosed mafic gneiss, anorthosite, gabbro and amphibolitized ultramafic rocks are scattered throughout the migmatite. The majority of the rocks contain variable amounts of cordierite, garnet and orthopyroxene. All of the rock types are intruded by late granitic pegmatite dikes.
The mafic gneiss is strongly foliated, commonly coarse-grained and consists of biotite, orthopyroxene, amphibole and 50% garnet. The mafic gneiss is interlayered with metasedimentary migmatite and intruded by peraluminous granitoid leucosome.
MINERAL DESCRIPTION:
The trench is sunk on a 2 m wide rusty zone in strongly garnetiferous mafic gneiss and migmatite. Sulphide
mineralization is concentrated in 2.5 to 15 cm wide, foliation parallel, sulphide veins consisting of 10 to 25%
chalcopyrite and 5 to 15% pyrite. Three grab samples collected from the trenches by Nickel Mining and
Smelting analyzed: 3.67% Cu, 10.12% Cu and 13.35% Cu.
ALTERATION DESCRIPTION:
Alteration is not well developed and mainly consists of weak chloritization adjacent to the sulphide veins.
145
MINERALIZED ZONE:
Name: Sogemines 1 Thickness: 2 m Strike: 2950 Dip: 900
Shape: Irregular Character: Vein
Classification: Hydrothermal, remobilized
ASSESSMENT FILES (Kenora Resident Geologist office):
52L07NW E-2 (A-9,A-11),L-3, P-1, P-2, Q-1.
ASSAYS:
Sample No.
Rock Name
Cu
(ppm)
Ni
(ppm)
Co
(ppm)
Cr
(ppm)
Mo
(ppm)
Au
(ppb)
Ag
(ppm)
94JRP-- 1160
grt-bt
gneiss
0.63%
< 40
75.6
13
<8
19
4
94JRP-- 1161
grt-bt
gneiss
5.60%
95
831
14
<8
436
8.9
Abbreviations: bt – biotite; grt - garnet
146
28. DEPOSIT NAME: SOGEMINES No.2 OCCURRENCE (SOBESKI CLAIM GROUP;
NORCO CLAIM GROUP 2)
COMMODITIES: Cu
UTM COORDINATES: 374239.0 mE, 5595590395.0 mN
UTM Datum: NAD27
MDI No.: MDI52L07NW00048
Mining Division: Kenora
Area Name: Werner Lake
UTM ZONE: 15
Claim Map No.: G-2654
LOCATION AND ACCESS:
The property is located immediately south of Upper Fortune Lake which is only accessible by floatplane. One
trench is located on the south shore of the lake and is clearly visible from the lake. A second trench is located
about 150 m southeast of the southeast corner of the lake and is located in a low area beside a large outcrop.
EXPLORATION HISTORY:
1957: Sogemines Development Co. Ltd. conducted geological mapping and sampling over a large claim group
that encompassed most of the area around Upper Fortune Lake. The company referred to this part of the property as the “Sobeski claim group”. The company diamond drilled 4 holes totalling 271.4 feet along the south
shore of the lake. The drill holes intersected narrow sections of disseminated chalcopyrite, pyrrhotite and magnetite in garnetiferous and biotitic paragneisses.
1963: Nickel Mining and Smelting Corp. optioned the property and conducted airborne and ground geophysical surveys and some sampling. The property was referred to as the “Norco claim group 2”. The company
diamond drilled 3 holes totalling 491 feet that were targeted on the lake shore trench. The diamond-drill holes
intersected narrow sections of disseminated chalcopyrite and magnetite in garnetiferous biotite gneiss and garnetiferous pegmatite.
1995: Staked by Canmine Resources Corporation.
GEOLOGICAL DESCRIPTION:
Province: Superior
Subprovince: English River
Metamorphism: 1) Type: Regional
2) Grade: Granulite
Assemblage: English River
The Sogemines No. 2 occurrence is located due south of an east-striking fault splay that extends from the
Werner-- Rex lakes fault at Werner Lake.
The Sogemines No. 2 occurrence is situated within diatexite and peraluminous granitoid rocks that contain
discontinuous pods and lenses of mafic gneiss, gabbro, anorthosite and altered ultramafic intrusive rocks.
LITHOLOGIC DESCRIPTION:
The rocks at Upper Fortune Lake are strongly deformed and variably mylonitized. A strong foliation strikes
east and dips moderately to the north. Numerous Z-drag folds with east-striking axial planes have shallow
plunges to the east. The majority of the rocks consist of diatexite and peraluminous granitoid rocks with variable (10 to 95%) amounts of garnet, cordierite and orthopyroxene porphyroblasts. Numerous discontinuous,
relatively small, enclaves of strongly deformed and highly metamorphosed mafic gneiss, anorthosite, gabbro
and amphibolitized ultramafic rocks are scattered throughout the migmatite. The majority of the rocks contain
variable amounts of cordierite, garnet and orthopyroxene. All of the rock types are intruded by late granitic
pegmatite dikes.
Mafic gneiss is strongly foliated, coarse-grained and consists of biotite, orthopyroxene, coarse black amphibole
and 50% garnet. The mafic gneiss is interlayered with metasedimentary migmatite and intruded by peraluminous granitoid leucosome.
Sogemines mapped 3 main types of gneisses on the property: biotite-hornblende gneiss, garnet-hornblende
gneiss and siliceous garnet gneiss.
MINERAL DESCRIPTION:
The lakeshore trench is sunk on a 2 m wide mineralized zone striking 2680/900 in garnetiferous mafic gneiss
and migmatite. Sulphide mineralization consists of 2 to 5% chalcopyrite and 1 to 3% pyrite disseminated
throughout the mafic gneiss. A narrow garnetiferous quartz vein, exposed in the trench, also contains chalcopyrite. Disseminated sulphide mineralization occurs in an outcrop exposure on the lakeshore, approximately
120 m west of the trench. About 10% disseminated chalcopyrite and pyrite are hosted within small enclaves of
147
biotite-garnet schists enclosed within pink weathering, coarse-grained, garnetiferous and feldspar-phyric peraluminous granite. The biotite-garnet schist contains up to 80% garnet porphyroblasts. The second trench,
south of the lake, has been sunk on 15 cm wide, foliation parallel and extension sulphide veins consisting of
chalcopyrite and pyrite. The veins are hosted within a biotite-amphibole-garnet rock.
Sogemines mapped an east-striking mineralized zone along the south shore of the lake. Chalcopyrite was reported to occur in narrow, massive veins up to 8 cm wide or as disseminations in garnet-hornblende gneiss.
The company traced the mineralization for approximately 5000 feet along strike. About 10 other scattered
copper occurrences were discovered south of the lake but none of these were located by the author.
ALTERATION DESCRIPTION:
Alteration is not well developed and mainly consists of weak chloritization adjacent to the sulphide veins.
MINERALIZED ZONE:
Name: Sogemines 2 Thickness: 2 m Strike: 2830 Dip: 900
Shape: Irregular Character: Disseminated, vein
Classification: Hydrothermal, remobilized
ASSESSMENT FILES (Kenora Resident Geologist office):
52L07NW E-2 (A-9,A-11), L-3, Q-1, and Q-2.
ASSAYS:
Sample No.
Rock Name
Cu
(ppm)
Ni
(ppm)
Co
(ppm)
Cr
(ppm)
Mo
(ppm)
Au
(ppb)
Ag
(ppm)
94JRP-- 1165*
mafic gneiss
999
75
35.9
79
<8
23
2
94JRP-- 1166*
mafic gneiss
3005
78
48.4
113
<8
24
2
94JRP-- 1168*
quartz vein
3.0%
< 40
62.9
47
<8
105
6
94JRP-- 1170
mafic gneiss
2.20%
< 40
68.6
18
42.7
215
12.4
94JRP-- 1171
mafic gneiss
12.0%
< 40
58.2
9
<8
566
8.4
94JRP-- 1172
mafic gneiss
0.86%
< 40
64.5
16
15.2
181
5
* - samples taken from the lakeshore trench.
148
29. DEPOSIT NAME: WERNER LAKE COBALT MINE
COMMODITIES: Co, Cu, As, Au, Ni, Zn
UTM COORDINATES: 360203.0 mE, 5592377.0 mN
UTM Datum: NAD27
MDI No.: MDI52L07NW00003
Mining Division: Kenora
Area Name: Werner Lake
UTM ZONE: 15
Claim Map No.: G-2654
Mining Location: KRL 33181
LOCATION AND ACCESS:
The property is accessible from the Gordon Lake mine road. The shaft, adit and waste rock dump is visible on
the north side of the road.
EXPLORATION HISTORY:
1920: A mineralized zone 150 feet long and 10 feet wide averaging 2.08% Co discovered by M. Carlson.
1925: The mineralized zone was sampled and assayed by Rex Taylor of Deloro Smelting and Refining Co.
The claims were allowed to lapse.
1928: Staked by Kenora Prospectors and Miners Ltd. who developed trenches and test pits and sunk a shaft to
a depth of 35 feet. A mineralized zone 100 feet long and 6 to 12 feet wide was exposed.
1932: A 100-foot long open cut was developed and 70 tons of ore, containing about 20 000 pounds of cobalt
(average grade of 18 to 20% Co) was shipped by air to Norwood, Ohio for processing.
1940-- 1944: The property was leased to Norman B. Davis of Ottawa. The ore was handcobbed until 1942
when a 25 ton/day mill was flown in and erected at the mine site. About 1200 feet of diamond drilling was
completed in 1942. An adit was driven 42 feet and a 2-compartment vertical shaft was sunken 20 feet in 1943.
The shaft was completed to a total depth of 40 feet below the adit level. A total of 123,386 pounds of Co was
shipped during the period 1940-- 1944. The mine closed in 1944 when a contract with Metals Reserve Co. was
cancelled. Total production is reported as 143,386 pounds of cobalt. Channel samples across the ore zone analyzed as high as 7.8% Co and 2.4% Cu. Nickel values as high as 0.5% were obtained from grab samples. The
average grade of the deposit is approximately 2.2% Co and 0.74% Cu.
1957: About 3000 feet of diamond drilling was conducted.
1994-- 1996: Canmine Resources Corp. optioned the property from Falconbridge Inc. and conducted ground
and airborne geophysical surveys, completed about 160 diamond-drill holes totalling approximately 75,000
feet and initiated clean-up operations at the mine site. Approximately 3100 tonnes of mineralized material was
shipped to Sudbury for metallurgical testing.
GEOLOGICAL DESCRIPTION:
Province: Superior
Subprovince: English River
Metamorphism: 1) Type: Regional
2) Grade: Amphibolite
Assemblage: English River
Cobalt-copper sulphide mineralization is erratically distributed within the Werner Lake cobalt-copper zone: a
1 to 30 m wide, east-striking, deformation zone of mixed lithologies that include stratabound skarnoid deposits. The zone hosts the Werner Lake cobalt mine, the West and East zone cobalt occurrences and some minor
showings of disseminated copper sulphide mineralization in ultramafic rocks. The cobalt-copper zone extends
for a strike length of 4.14 km from the north shore of Almo Lake to the northwest shore of Werner Lake and
was first described by Derry (1931) as a “replacement vein” in a “garnet-rich band which may be traced for a
mile or more along the strike”. The zone occurs within metasedimentary migmatite about 200 m north of the
Werner-- Rex lakes fault and is intruded by massive granite-granodiorite sills at Almo and Werner lakes. A
northwest-striking crossfault, coincident with a major linear, topographic low, is interpreted (Chown 1955;
Carlson 1958) to extend along the west side of the mine.
The cobalt-copper zone consists of a linear, sinuous, anastomosing band of strongly foliated biotite-garnet
schist intermixed with foliation parallel, granitoid and pegmatoid leucosome veins of quartz + plagioclase +
biotite and quartz + potassium feldspar + biotite + garnet. The leucosome veins are folded, discontinuous,
irregular and strongly contorted in some locations. The biotite-garnet schist is also interlayered with strongly
foliated amphibolitized gabbro; metatexite; and small (0.5 to 2 m in size) pods or boudins of dark green-black,
biotitic, ultramafic rock.
The cobalt-copper zone at Werner Lake extends along the contact between a granite-granodiorite intrusion to
the south and metatexite to the north. The metatexite consists of moderately to strongly foliated wacke and
149
pelitic paleosome with inclusions of mafic gneiss, amphibolitized gabbro and ultramafic pods. The granitegranodiorite intrusion is buff-grey to pink weathering, massive and porphyritic with potassium feldspar phenocrysts ranging from 1 to 6 cm in size. The intrusion is foliated along its north margin and contains diffuse pegmatitic phases and scattered xenoliths of wacke and gabbro. The granite-granodiorite intrusion contains minor,
fine-grained, disseminated pyrite and is weakly sericitic, chloritic, carbonatized and variably epidotized at the
Werner Lake cobalt mine.
The portion of the cobalt-copper zone, adjacent to the granite-granodiorite intrusion, hosts high grade cobaltcopper sulphide mineralization in lenses and layers of calcsilicate, amphibole rock and biotite-garnet schist at
the Werner Lake cobalt mine and West cobalt zone occurrence. The intrusion intrudes and cuts off the cobaltcopper zone on the northwest shore of Werner Lake at the East cobalt zone occurrence.
LITHOLOGIC DESCRIPTION:
The skarnoid is situated at an intrusive contact between a granite-granodiorite intrusion in the footwall (south
side) and metatexite in the hanging wall (north side). Foliation and layering in the skarnoid rocks strike about
2600 and dip steeply north. Geometry and size of the skarnoid is difficult to determine due to poor exposure
and excavation during mining , however, the mineralized zone was reported to be 2 to 4 m wide (Wright 1932;
Chown 1955; Carlson 1958). The intrusive contact with the granite-granodiorite is parallel or subparallel to
layering in the metatexite and skarnoid assemblage. Skarn is commonly confined to narrow but vertically extensive zones where intrusive contacts are subparallel to bedding planes (Meinert 1992), therefore, the skarnoid
at the Werner Lake cobalt mine may have a similar form.
Three main rock units were identified (Chown 1955) in the mineralized zone at the Werner Lake cobalt mine
and West cobalt zone: 1) a marginal biotite-garnet schist or gneiss on the north side or hanging wall of the mineralized zone; 2) an amphibole-rich rock on the south side or foot wall of the zone; and 3) a “quartz-poor biotite-feldspar schist” that occurs between the biotite-garnet schist and the amphibole-rich rock. The “biotitefeldspar” schist was described as the host of the high grade ore (Chown 1955). Biotite-feldspar schist was not
identified by the author, instead, the author found a calcsilicate rock containing high grade cobalt mineralization.
Calcsilicate rocks are pale green-grey, massive, fine- to medium-grained and dominantly composed of whitegrey calcite. The rock contains a prograde mineral assemblage calcite + forsterite (magnesian olivine) + magnetite + hercynite-spinel that is strongly retrograded to antigorite, chondrodite, clinochlore (magnesian chlorite) and clinozoisite (iron-poor epidote). In thin section, the rock is granoblastic with large polygonal grains
of calcite; radiating fibrous patches of antigorite pseudomorphs after forsterite or coronas of antigorite along
the rims of altered olivine; disseminated anhedral magnetite intergrown with calcite and olivine; minor subhedral green hercynite containing magnetite lamellae and magnetite on rims and fractures; and rare aggregates of
pale yellow chondrodite formed by the alteration of olivine. Narrow veinlets of amphibole, clinochlore and
clinozoisite transect the calcsilicate assemblage and are associated with sulphide minerals. A few narrow layers of calcite + magnetite + diopside were identified by the author at the West cobalt zone but diopside was not
recognized at the mine.
Large blocks of calcsilicate rock, in the rock dump at the mine, contain 8 to 20 cm wide bands or layers of
dark green, very coarse-grained amphibole. In thin section, narrow amphibole veinlets and fractures transect
the calcsilicate rocks. The amphibole layers and veins are dense and massive consisting of large (4 cm x 10
cm), euhedral to subhedral, dark green crystals of magnesian hastingsite intergrown with coarse, dark green to
black magnesian hornblende and interstitial tremolite, magnetite, quartz, feldspar, hercynite and sulphide minerals. The amphibole layers are variably retrograded to clinochlore and clinozoisite. The amphibole layers
and veins overprint the earlier calcsilicate assemblage.
The marginal biotite-garnet schist is strongly foliated with coarse (up to 2 cm in diameter), red, subhedral to
euhedral porphyroblasts of magnesian almandine garnet embedded in a coarse biotite matrix with minor interstitial quartz. The garnet occurs in clotty aggregates or as disseminated crystals ranging in abundance from 15
to 95% of the rock. The schist is commonly intruded by foliation parallel granitoid and pegmatoid leucosome
and variably altered to clinochlore and clinozoisite associated with disseminated sulphide mineralization.
All of the lithologies described above are variably foliated and deformed. Coarse-grained amphibolelayers and
calcsilicate at the cobalt mine are massive and do not appear to have a foliation. Chown (1955) observed dragfolded layers of sulphide mineralization at the cobalt mine.
MINERAL DESCRIPTION:
Sulphide minerals consist of cobaltite, chalcopyrite and pyrite with secondary erythrite and malachite. Oxide
minerals consist of magnetite and hercynite.
150
Chown (1955) reported that the mineralized zone at the Werner Lake cobalt mine consisted of disseminated
sulphide minerals that enclosed small, irregular lenses of massive sulphide mineralization situated on either
side of the mineralized zone. Carlson (1958) reported that the largest mineralized lens at the cobalt mine was
3 m x 1.2 m x 1.5 m in size. Assessment file reports (Assessment File 52L07NW S-1) describe the cobalt and
copper sulphide mineralization as “spotty and erratic”. The assessment reports indicate that the best sulphide
mineral lenses were high grade but not more than a few feet long and under a foot in width (Assessment File
52L07NW S-1). The sulphide lenses are also described as “stopping and starting suddenly” and “jumping
from side to side of the garnetiferous zone” (Assessment File 52L07NW S-1). Diamond drilling conducted at
the cobalt mine by Canmine Resources Corporation intersected 3 mineralized, en echelon lenses (Canmine
Resources Corporation, News Release, February 23, 1996; W. Ferreira, Canmine Resources Corporation, personal communication, 1996).
All of the skarnoid rocks are variably mineralized with cobaltite, chalcopyrite and pyrite (3 to 15% combined
sulphide minerals) but the calcsilicate rocks contain the most abundant and highest grade cobalt mineralization
with up to 25 or 30% combined sulphide minerals. Cobaltite is the most abundant sulphide mineral with grain
size ranging from < 2 mm to 1 cm. Sulphide minerals in calcsilicate occur in bands or layers (up to 10 cm
thick) of disseminated, fine- to coarse-grained, euhedral to subhedral grains that replace and overprint silicate
minerals; invade silicate minerals along fractures; and replace magnetite. Sulphide minerals also occur along
narrow veinlets and fractures with associated chlorite, clinozoisite and amphibole.
Chalcopyrite, pyrite, pyrrhotite and minor cobaltite are disseminated throughout the amphibole layers. Sulphide minerals may be interstitial to amphibole and overprint and replace silicate minerals. Chalcopyrite “corrodes” the edges of amphibole crystals and invades silicate minerals along fractures. Relatively minor cobaltite, chalcopyrite and pyrite are disseminated in the biotite-garnet schist.
Other minor minerals identified in the ores from the Werner Lake cobalt mine are: linneaite (Co+2Co2+3S4)
and siegenite (Ni, Co)3S4 (Rose 1951); sphalerite (Godard 1931); annabergite and hematite (Chown 1955); and
minor grains of tetrahedrite and bornite (E.O. Chisholm, assessment file 52L07NW M-1).
Mineral textures and relationships suggest that the majority of sulphide and oxide minerals were deposited after the formation of prograde silicate and carbonate mineral assemblages.
Diamond drilling conducted by Canmine Resources Corp. intersected numerous mineralized sections at the
Werner Lake cobalt mine, such as: 1.48% Co, 0.27% Cu and 0.03 ounce Au per ton across 4 m in Lens No.2;
0.29% Co and 0.66% Cu across 7.6 m in Lens No.3; and 0.18% Co and 0.11% Cu across 8 m in Lens No.3
(Canmine Resources Corp., News Release, February 23, 1996).
ALTERATION DESCRIPTION:
The protolith for the replacement skarnoid at the Werner Lake cobalt mine was a deformed and serpentinized
ultramafic rock. Metasomatism and replacement of the altered ultramafic protolith accompanied the emplacement and crystallization of the syn- to late-tectonic granite-granodiorite intrusion in the footwall of the deposit.
The skarnoid formation resulted in prograde mineral assemblages that constitute the 3 main rock types at the
mine. Hydrous retrograde alteration accompanied final cooling of the skarnoid, therefore, prograde minerals
were replaced by antigorite and chondrodite (after forsterite), clinozoisite (iron-poor epidote) and clinochlore
(magnesian chlorite).
MINERALIZED ZONE:
Name: Cu-Co zone Length: 50 m Thickness: 3.0 m Strike: 2620 Dip: 850
Shape: Irregular Structure: Contact, Fault Character: Layers, lenses
Classification: Contact metamorphic, hydrothermal, skarnoid
PAST PRODUCTION:
COMMODITY
PRODUCTION
AVERAGE GRADE
Cobalt
146 386 pounds of
cobalt
2.2 % Co
Copper
SOURCE: Carlson 1958
ASSESSMENT FILES (Kenora Resident Geologist office):
52L07NW M-1, S-1 and S-2.
151
0.75% Cu
ASSAYS:
Sample No.
Rock
Name
94JRP1099
Au
(ppb)
Ag
Mo
As
(ppm) (ppm) (ppm)
Cr
Co
Ni
Cu
Zn
(ppm) (ppm) (ppm) (ppm) (ppm)
calcsilicate 357
4.4
<8
1.90%
151
22074
452
1875
96.2
94JRP1100
amphibole
421
4
<8
> 6000
839
36300
652
4731
401.7
94JRP1101
amphibole
1246
4
<8
> 6000
330
14240
< 40
1.9%
127
94JRP1102
amphibole
356
5
<8
< 100
65
2036
< 40
0.7%
13340
94JRP1103
gabbro
<3
4
<8
42
275
111.2
71
< 100
66.85
A grab sample collected at the mine by Chisholm (1949) assayed 0.01 ounce Pt per ton and 0.07 ounce Pd per
ton. Trace to nil platinum and palladium values were obtained from samples collected by the author.
152
30. DEPOSIT NAME: WERNER LAKE COBALT -- EAST ZONE
COMMODITIES: Co, Cu, Au
UTM COORDINATES: 360851.0 mE, 5591319.0 mN
UTM Datum: NAD27
MDI No.: MDI52L07NW00043
Mining Division: Kenora
Area Name: Werner Lake
9386
UTM ZONE: 15
Claim Map No.: G-2654
Mining Location: KRL 9385 and
LOCATION AND ACCESS:
Accessible from the Gordon Lake mine road. Drive down the road to the north shore of Werner Lake.
Launch a canoe into the lake at the large culvert. Paddle along the east shore of the lake. The trench and rusty
rock dump are visible from the lake.
Test pits and trenches are also located on the west side of the Gordon Lake mine road. These trenches are on
strike with the trench on the lakeshore and are situated on the last large outcrop, on the west side of the road,
before the large culvert at Werner Lake.
EXPLORATION HISTORY:
1920: A mineralized zone 150 feet long and 10 feet wide averaging 2.08% Co was discovered by M. Carlson
at the site of the Werner Lake mine.
1928-- 1932: Staked by Kenora Prospectors and Miners Ltd. who developed several trenches and test pits east
and west of the Werner Lake mine. The development was concentrated on an east-striking, garnet-rich zone
within metasedimentary migmatite. Four trenches were developed on the East zone across a strike length of
230 feet.
1942: Frobisher Exploration Company Ltd. conducted sampling, geological mapping and diamond drilling on
the property.
1968: The property was acquired by Falconbridge Nickel Mines Ltd.
1994-- 1996: Canmine Resources Corp. optioned the property from Falconbridge Inc. and conducted ground
and airborne geophysical surveys and completed an extensive diamond-drill program on the West zone and at
the Werner Lake cobalt zone. No diamond drilling was reported on the East zone.
GEOLOGICAL DESCRIPTION:
Province: Superior
Subprovince: English River
Metamorphism: 1) Type: Regional
2) Grade: Amphibolite
Assemblage: English River
Cobalt-copper sulphide mineralization is erratically distributed within the Werner Lake cobalt-copper zone: a
1 to 30 m wide, east-striking, deformation zone of mixed lithologies that include stratabound skarnoid deposits. The zone hosts the Werner Lake cobalt mine, the West and East zone cobalt occurrences and some minor
showings of disseminated copper sulphide mineralization in ultramafic rocks. The cobalt-copper zone extends
for a strike length of 4.14 km from the north shore of Almo Lake to the northwest shore of Werner Lake and
was first described by Derry (1931) as a “replacement vein” in a “garnet-rich band which may be traced for a
mile or more along the strike”. The zone occurs within metasedimentary migmatite about 200 m north of the
Werner-- Rex lakes fault and is intruded by massive granite-granodiorite sills at Almo and Werner lakes.
The cobalt-copper zone consists of a linear, sinuous, anastomosing band of strongly foliated biotite-garnet
schist intermixed with foliation parallel, granitoid and pegmatoid leucosome veins of quartz + plagioclase +
biotite and quartz + potassium feldspar + biotite + garnet. The leucosome veins are folded, discontinuous,
irregular and strongly contorted in some locations. The biotite-garnet schist is also interlayered with strongly
foliated amphibolitized gabbro; metatexite; and small (0.5 to 2 m in size) pods or boudins of dark green-black,
biotitic, ultramafic rock.
The cobalt-copper zone at the East zone extends along the contact between a granite-granodiorite intrusion to
the south and metatexite to the north. The metatexite consists of moderately to strongly foliated wacke and
pelitic paleosome with inclusions of mafic gneiss, amphibolitized gabbro and ultramafic pods. The granitegranodiorite intrusion is buff-grey to pink weathering, massive and porphyritic with potassium feldspar phenocrysts ranging from 1 to 6 cm in size. The intrusion is foliated along its north margin and contains diffuse pegmatitic phases and scattered xenoliths of wacke and gabbro. The granite-granodiorite intrusion is weakly sericitic and variably epidotized at the East zone.
The portion of the cobalt-copper zone, adjacent to the granite-granodiorite intrusion, hosts high grade cobaltcopper sulphide mineralization in lenses and layers of calcsilicate, amphibole rock and biotite-garnet schist.
153
The intrusion intrudes and cuts off the cobalt-copper zone on the northwest shore of Werner Lake at the East
cobalt zone occurrence.
LITHOLOGIC DESCRIPTION:
Host rocks at the East zone trench on the east shore of Werner Lake consists of a strongly deformed, contorted,
mixed assemblage of strongly epidotized, chloritic, coarse-grained biotite-garnet schist and amphibole rock.
The calcsilicate rocks were not recognized at this occurrence. The rocks contain almost solid layers of massive magnetite and large garnets up to 3 or 4 cm in size.
Ultramafic rock: A medium- to coarse-grained, dark green-black rock composed of dark green amphibole intruded by granitic pegmatite veins. The amphibole is moderately to strongly altered to clinozoisite and clinochlore. This ultramafic rock was only observed in the trench on the east shore of Werner Lake.
Biotite-garnet schist: A medium- to coarse-grained, strongly foliated, schistose rock consisting of 25 to 90%
red-brown, magnesian almandine garnet and biotite retrograded to clinochlore and clinozoisite. The schist is
interlayered with quartz-feldspar-biotite pegmatite.
Granite-granodiorite: Massive to foliated, medium-grained and pink weathering outcrop surfaces with diffuse
pegmatitic phases. The granite-granodiorite is megacrystic with large pink potassic feldspar phenocrysts. The
granite-granodiorite contains xenoliths of mafic gneiss and migmatite. Feldspars are weakly altered to sericite
and abundant epidote occurs along fracture surfaces.
Migmatite: Metatexite contains 40 to 90% moderately to strongly foliated wacke and pelitic paleosome
(quartz-plagioclase-biotite) interlayered with medium- to coarse-grained granitoid and pegmatoid leucosome
and contains inclusions of mafic gneiss and gabbro. The migmatite hosts up to 75 to 80% garnet porphyroblasts in some locations.
Peridotite/pyroxenite: Small, football-size pods of black-brown to dark green-black ultramafic rocks recrystallized and replaced by amphibole and biotite. Commonly occurs with minor amounts of medium-grained, biotitic gabbro.
MINERAL DESCRIPTION:
Sulphide minerals consist of cobaltite, chalcopyrite and pyrite with secondary erythrite and malachite. Oxide
minerals consist of disseminated and semimassive magnetite.
The pits and trenches west of the Gordon Lake mine road are weakly mineralized with 1-- 2% combined disseminated pyrite and chalcopyrite. The sulphide minerals are fine-grained, subhedral and hosted within the
biotite-garnet schist, gabbro and mafic gneiss.
The best sulphide mineralization occurs in the trench on the east shore of Werner Lake and consists of abundant chalcopyrite (25 to 30%) and pyrite with minor cobaltite (2 to 5%). The sulphide minerals are concentrated in large, irregular, coarse aggregates interstitial to amphibole and garnet. Disseminated magnetite
(5-- 15%) occurs throughout the host rocks and is concentrated in narrow layers of almost solid magnetite
(80-- 90%). Magnetite also appears to have been sulphidized by chalcopyrite and pyrite.
ALTERATION DESCRIPTION:
The amphibole, garnet and biotite are weakly to strongly altered to clinochlore and clinozoisite. Feldspar is
almost completely altered to epidote.
MINERALIZED ZONE:
Name: East zone Length: n/a Thickness: n/a Shape: Irregular Structure: Contact
Character: Disseminated
Classification: Contact metamorphic, hydrothermal, skarnoid
ASSESSMENT FILES (Kenora Resident Geologist office):
52L07NW S-1.
154
ASSAYS:
Sample No.
Rock
Name
Au
(ppb)
Ag
Mo
As
Cr
Co
Ni
Cu
Zn
(ppm) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm)
94JRP1104*
bt-grt
schist
<3
<2
<8
<6
12
25.7
< 40
158
89
94JRP1105*
gabbro
476
4
<8
<6
131
68.5
< 40
240
127
94JRP1117
grt-ampbt rock
868
9.2
<8
<6
95
4659
167
3.4%
142
94JRP1119
grt-ampbt rock
35
11
9.15
<6
43
1655
< 40
0.7%
79.04
94JRP1120
grt-ampbt rock
1154
11.7
<8
17
2
5156
447
8.10%
268
amp – amphibole; bt – biotite; grt – garnet
* - Samples taken from 2 trenches on the west side of Werner Lake and west of the Gordon Lake mine road.
All other samples taken from the trench on the east shore of the lake.
155
31. DEPOSIT NAME: WERNER LAKE COBALT -- WEST ZONE
COMMODITIES: Co, Cu, As, Au
UTM COORDINATES: 359575.0 mE, 5591319.0 mN
UTM Datum: NAD27
MDI No.: MDI52L07NW00042
Mining Division: Kenora
Area Name: Werner Lake
and 33183
UTM ZONE: 15
Claim Map No.: G-2654
Mining Location: KRL 33182
LOCATION AND ACCESS:
The property is accessible from the Gordon Lake mine road. Park on the side of the road and walk about 180
m due north to the trenches. Follow the garnet-rich zone east and west along strike from the main trench to
find other trenches and pits. The West Zone consists of at least 6 trenches over a strike length of about 400 m.
The trenches have been developed on the garnet-rich cobalt-copper zone west of the Werner Lake cobalt mine.
The main trench hosts the best sulphide mineralization including cobaltite. The other trenches are weakly
mineralized with up to 5% chalcopyrite and pyrite in biotite-garnet schist with coarse-grained, biotite-rich pegmatite and minor quartz veins. The biotite-garnet schist (up to 90% garnet) is interlayered with garnetiferous
migmatite (60% garnet); minor mafic gneiss; gabbro and small pods of dark green-black ultramafic rock. The
mineralized zone is approximately 1.8 to 3.1 m wide in these trenches.
Note: The occurrence has changed considerably since the author’s visit since it is now the site of an underground ramp developed by Canmine Resources Corp.
EXPLORATION HISTORY:
1920: A mineralized zone 150 feet long and 10 feet wide averaging 2.08% Co discovered by M. Carlson.
1928-- 1932: Staked by Kenora Prospectors and Miners Ltd. who developed several trenches and test pits east
and west of the Werner Lake mine. The development was concentrated on an east-striking garnet-rich zone
within the metasedimentary migmatites. Analyses reported from chip samples taken from the west trenches
are as follows: 0.07% Co across 11 feet; 0.09% Co across 10 feet; 0.15% Co across 20 feet; 0.22% Co across
20.5 feet.
1942: Frobisher Exploration Company Ltd. conducted sampling, geological mapping and diamond drilling on
the property.
1968: The property was acquired by Falconbridge Nickel Mines Ltd.
1994-- 1997: Canmine Resources Corp. optioned the property from Falconbridge Inc. and conducted ground
and airborne geophysical surveys and completed an extensive diamond-drill program. Drilling at the West
zone delineated a mineralized section consisting of 14 000 tonnes averaging 1.57% Co, 0.26% Cu and 0.113
ounce Au per ton. In February, 1996 Canmine announced plans to bulk sample this section beginning in June,
1996 (Canada Stockwatch, February 26, 1996, p.11). Diamond drilling results also indicate that the West zone
has a mineralized strike length of about 400 m and has been traced 100 m downrake with intercepts of up to 17
m (Canada Stockwatch, January 25, 1996, p.6).
The company commenced underground mining operations in late 1996 by ramping into the West zone and extracting about 10 000 tonnes of cobalt ore before the end of 1997. A total of 847 feet of underground ramping,
drifting and raising was completed. Underground chip sampling gave the following cobalt values: 3.0% Co,
15% Co, 15.7% Co, 18.5% Co and 20% Co (Canmine Resources, News Release, October 23, 1997).
GEOLOGICAL DESCRIPTION:
Province: Superior
Subprovince: English River
Metamorphism: 1) Type: Regional
2) Grade: Amphibolite
Assemblage: English River
Cobalt-copper sulphide mineralization is erratically distributed within the Werner Lake cobalt-copper zone: a
1 to 30 m wide, east-striking, deformation zone of mixed lithologies that include stratabound skarnoid deposits. The zone hosts the Werner Lake cobalt mine, the West and East zone cobalt occurrences and some minor
showings of disseminated copper sulphide mineralization in ultramafic rocks. The cobalt-copper zone extends
for a strike length of 4.14 km from the north shore of Almo Lake to the northwest shore of Werner Lake and
was first described by Derry (1931) as a “replacement vein” in a “garnet-rich band which may be traced for a
mile or more along the strike”. The zone occurs within metasedimentary migmatite about 200 m north of the
Werner-- Rex lakes fault and is intruded by massive granite-granodiorite sills at Almo and Werner lakes.
The cobalt-copper zone consists of a linear, sinuous, anastomosing band of strongly foliated biotite-garnet
schist intermixed with foliation parallel, granitoid and pegmatoid leucosome veins of quartz + plagioclase +
156
biotite and quartz + potassium feldspar + biotite + garnet. The leucosome veins are folded, discontinuous,
irregular and strongly contorted in some locations. The biotite-garnet schist is also interlayered with strongly
foliated amphibolitized gabbro; metatexite; and small (0.5 to 2 m in size) pods or boudins of dark green-black,
biotitic, ultramafic rock.
The cobalt-copper zone at Werner Lake extends along the contact between a granite-granodiorite intrusion to
the south and metatexite to the north. The metatexite consists of moderately to strongly foliated wacke and
pelitic paleosome with inclusions of mafic gneiss, amphibolitized gabbro and ultramafic pods. The granitegranodiorite intrusion is buff-grey to pink weathering, massive and porphyritic with potassium feldspar phenocrysts ranging from 1 to 6 cm in size. The intrusion is foliated along its north margin and contains diffuse pegmatitic phases and scattered xenoliths of wacke and gabbro.
The portion of the cobalt-copper zone, adjacent to the granite-granodiorite intrusion, hosts high grade cobaltcopper sulphide mineralization in lenses and layers of calcsilicate, amphibole layers and biotite-garnet schist at
the West cobalt zone occurrence.
LITHOLOGIC DESCRIPTION:
The skarnoid is situated at an intrusive contact between a granite-granodiorite intrusion in the footwall (south
side) and metatexite in the hanging wall (north side). Foliation and layering in the skarnoid rocks is east-striking and dips steeply north. The mineralized zone is 2 to 4 m wide with disseminated sulphide mineralization
enclosing small high grade sulphide lenses and layers. The intrusive contact with the granite-granodiorite is
parallel or subparallel to layering in the metatexite and skarnoid assemblage. Skarn is commonly confined to
narrow but vertically extensive zones where intrusive contacts are subparallel to bedding planes (Meinert
1992), therefore, the skarnoid deposit at the West zone may have a similar form.
Calcsilicate rocks are pale green-grey, massive, fine- to medium-grained and dominantly composed of whitegrey calcite. The rock contains a prograde mineral assemblage calcite + forsterite (magnesian olivine) + magnetite that is strongly retrograded to antigorite, clinochlore (magnesian chlorite) and clinozoisite (iron-poor
epidote). In thin section, the rock is granoblastic with large polygonal grains of calcite; radiating fibrous
patches of antigorite pseudomorphs after forsterite or coronas of antigorite along the rims of altered olivine;
and disseminated anhedral magnetite intergrown with calcite and olivine. Narrow veinlets of amphibole, clinochlore and clinozoisite transect the calcsilicate assemblage and are associated with sulphide minerals. A
few narrow layers of calcite + magnetite + diopside were identified by the author at the West cobalt zone but
diopside was not recognized at the mine. The calcsilicate rocks are not as abundant at the West zone as they
are at the Werner Lake cobalt mine and commonly occur in narrow, discontinuous layers.
Amphibole layers at the West cobalt zone are foliation parallel and subparallel to the margins of the mineralized zone. The amphibole layers are dense and massive consisting of large (4 cm x 10 cm), euhedral to subhedral, dark green crystals of magnesian hastingsite intergrown with coarse, dark green to black magnesian hornblende and interstitial tremolite, magnetite, quartz, feldspar and sulphide minerals. The amphibole is variably
retrograded to clinochlore and clinozoisite. A fine-grained, pale green, 2 to 6 cm wide, metasomatic reaction
zone or alteration front, consisting of clinozoisite + magnetite + clinochlore, occurs at the interface between an
amphibole layer and biotite-garnet schist. Diffuse clinozoisite-clinochlore alteration extends outward from
either side of the reaction zone with the most intense alteration in the biotite-garnet schist. The amphibole
layers or veins overprint the earlier calcsilicate assemblage.
The marginal biotite-garnet schist is strongly foliated with coarse (up to 2 cm in diameter), red, subhedral to
euhedral porphyroblasts of magnesian almandine garnet embedded in a coarse biotite matrix with minor interstitial quartz. The garnet occurs in clotty aggregates or as disseminated crystals ranging in abundance from 15
to 95% of the rock. The schist is commonly intruded by foliation parallel granitoid and pegmatoid leucosome
and variably altered to clinochlore and clinozoisite associated with disseminated sulphide mineralization.
All of the lithologies described above are variably foliated and deformed. Amphibole layers and calcsilicate
rocks at the West cobalt zone are strongly deformed and foliated. Some calcsilicate layers at the West zone
also appear to be boudinaged into long discontinuous lenses. Mineralized lenses at the West zone were reported to plunge 450 to the east in underground exposures (Canmine Resources Corp., News Release, October
22, 1997).
MINERAL DESCRIPTION:
Sulphide minerals consist of cobaltite, chalcopyrite, pyrite, pyrrhotite and molybdenite with secondary erythrite and malachite. Oxide minerals consist of magnetite and hercynite.
Rocks in the trenches host disseminated, fine- to medium-grained, euhedral to subhedral cobaltite (5-- 10%);
pyrite (2-- 5%); pyrrhotite (2-- 5%); chalcopyrite (2-- 5%); erythrite (pink cobalt bloom); azurite and malachite.
157
About 1-- 2% fine-grained flakes of molybdenite were observed in the main trench. Magnetite is part of the
skarnoid mineral assemblage and is disseminated throughout the calcsilicate rock, amphibole rock and biotitegarnet schist. Sulphide minerals overprint or overgrow all silicate and gangue minerals. Magnetite is commonly sulphidized to chalcopyrite, pyrite or cobaltite. These textures indicate that sulphide minerals were deposited during the final cooling of the skarnoid and accompanied the retrograde alteration of the prograde skarnoid mineral assemblage.
Diamond drilling by Canmine at the West cobalt zone intersected numerous mineralized sections, including:
0.85% Co and 0.31% Cu across 17.27 m in DDH J-40 (Canada Stockwatch, December 13, 1995); 0.06% Co
and 0.14% Cu across 9 m in DDH J-9; 0.31% Co, 0.5% Cu, 0.11 ounce Au per ton and 0.12 ounce Ag per ton
across 8.72 m in DDH J-10; and 0.17% Co, 2.29% Cu, 0.036 ounce Au per ton and 0.39 ounce Ag per ton
across 4.56 m in DDH J-12 (Canmine Resources Corp., News Release, October 5, 1995).
ALTERATION DESCRIPTION:
The protolith for the replacement skarnoid at the West zone was a deformed and serpentinized ultramafic rock.
Metasomatism and replacement of the ultramafic protolith accompanied the emplacement and crystallization
of the syn- to late-tectonic granite-granodiorite intrusion in the footwall of the deposit. The skarnoid formation
resulted in prograde mineral assemblages that constitute the 3 main rock types at the West zone: biotite-garnet
(magnesian almandine) schist; amphibole rock (magnesian hastingsite-magnesian hornblende-tremolite) and
the calcsilicate rock (calcite-forsterite-magnetite). Retrograde alteration accompanied final cooling of the
skarnoid, therefore, prograde minerals were replaced by antigorite (after forsterite), clinozoisite (iron poor epidote) and clinochlore (magnesian chlorite).
MINERALIZED ZONE:
Name: West zone Length: 400 m Thickness: 10.0 m Strike: 2690 Dip: 850
Shape: Irregular Structure: Contact Character: Layers and lenses
Classification: Contact metamorphic, hydrothermal, skarnoid
RESERVES:
COMMODITY
GRADE
TONNAGE
Cobalt
Copper
Gold
1.57 %
14 000 tonnes
0.26%
0.113 opt
SOURCE: Canada Stockwatch, February 26, 1996, p.11.
ASSESSMENT FILES (Kenora Resident Geologist office):
52L07NW S-1.
158
CATEGORY
Recoverable
Recoverable
Recoverable
ASSAYS:
Sample No.
Rock
Name
Au
(ppb)
Ag
Mo
As
Cr
Co
Ni
Cu
Zn
(ppm) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm)
94JRP1091
amphibole
168
3
15.57
411
72
2191
144
0.77%
56.3
94JRP1092
amphibole
57
4
<8
2443
174
3072
< 40
788
112.1
94JRP1094
amphibole
58
4
12.84
1557
152
2204
<40
797
63.76
94JRP1095
bt-grt
schist
110
6.2
<8
<6
287
312.3
< 40
0.79%
139.1
94JRP1096
bt-grt
schist
182
5
<8
<6
92
47.7
< 40
0.57%
77.59
94JRP1097
bt-grt
schist
209
4
<8
<6
162
62.81
< 40
0.53%
84.86
94JRP1098
bt-grt
schist
23
<2
<8
<6
750
116.7
< 40
509
142.4
Samples 1092, 1092 and 1094 were collected from the “Main trenches”; the other samples were collected from
a series of trenches located east of the Main trenches.
159
32. DEPOSIT NAME: WERNER LAKE--WEST ARM OCCURRENCE
COMMODITIES: Ni, Cu
UTM COORDINATES: 361710.0 mE, 5591921.0 mN
UTM Datum: NAD27
MDI No.: MDI52L07NW00044
Mining Division: Kenora
Area Name: Werner Lake
and 31829.
UTM ZONE: 15
Claim Map No.: G-2654
Mining Locations: KRL 31828
LOCATION AND ACCESS:
The West Arm occurrence is located about 240 m due east of Werner Lake at the extreme northwest end of the
lake. The occurrence is also about 300 m due south of the Gordon Lake mine road. The occurrence is most
easily accessed from the mine road. The pits at this occurrence were not located by the author, however,
abundant diamond-drill core is scattered on the outcrops.
EXPLORATION HISTORY:
1942: A. Vanderbrink and H. Byberg made several copper-nickel discoveries in and around the Gordon-- Werner lakes area.
1948: International Nickel Co. Ltd. conducted geological mapping and ground geophysical surveys over 15
contiguous mining claims that encompassed the West Arm occurrence.
1962: Canadian Nickel Co. conducted ground geophysical surveys.
1971: Consolidated Canadian Faraday Ltd. diamond drilled 12 holes at this occurrence. Almost all of the
holes intersected nickel-copper mineralization in a peridotite body.
GEOLOGICAL DESCRIPTION:
Province: Superior
Subprovince: English River
Metamorphism: 1) Type: Regional
2) Grade: Amphibolite
Assemblage: English River
The West Arm occurrence is situated on the Werner-- Rex lakes fault that extends along the contact between a
metasedimentary migmatite assemblage to the north and the tonalitic Marijane batholith. The fault strikes east
across the Manitoba-- Ontario provincial border through Reynar, Almo, Gordon, Werner and Rex lakes to Bug
Lake and beyond for a strike length of approximately 32 km. The fault strikes east and dips north at the West
Arm occurrence.
Deformed, metamorphosed and metasomatized gabbro, porphyritic gabbro and ultramafic pods are situated
within and adjacent to the Werner-- Rex lakes fault and may have originally been part of one stratiform, layered
intrusion. The ultramafic pods are relatively small, amphibolitized and recrystallized and host oxide and sulphide minerals such as magnetite, chromite, pyrrhotite and chalcopyrite.
LITHOLOGIC DESCRIPTION:
Metatexite, granitic pegmatite dikes and strongly foliated tonalitic rocks of the Marijane batholith are the dominant lithologies in the vicinity of the West Arm occurrence. The metatexite contains about 5% garnet porphyroblasts in the paleosome and peraluminous leucosome. Discontinuous lenses of fine- to medium-grained
strongly foliated gabbro occur within the metasedimentary rocks. A strong foliation strikes 2700 and dips
steeply to the north. Z-drag folding was also observed in the metatexite. Sulphide mineralization is hosted in
an ultramafic pod, unfortunately, the pod is not exposed.
Diamond-drill logs describe the ultramafic pod as a massive, altered, magnetic, fine-grained peridotite.
MINERAL DESCRIPTION:
Little information is available on the mineralization at this occurrence. Diamond-drill logs report disseminated
“sulphides”. Diamond-drill hole No. 1971-- 17 (Consolidated Canadian Faraday Ltd.) intersected thick peridotite between 366.0 to 582.7 feet which analyzed 0.43% Ni and 0.095% Cu across 216.7 feet.
ALTERATION DESCRIPTION:
Diamond-drill logs indicate that the peridotite is variably serpentinized, biotitic and chloritized. The ultramafic rocks also contain abundant calcite stringers; calcite-filled shears and calcite-filled “slips”. Thick biotitechlorite zones were intersected at the margins of the peridotite body.
160
ASSESSMENT FILES (Kenora Resident Geologist office):
52L07NW B-1, E-2 (A-4, B-1) and J-1.
161
THIS PAGE LEFT BLANK INTENTIONALLY
162
Bug Lake
163
1. DEPOSIT NAME: BUG LAKE OCCURRENCE (NORTH LAKESHORE SHOWING)
COMMODITIES: Cu, Ag
UTM COORDINATES: 385850.0 mE, 5587960.0 mN
UTM Datum: NAD27
MDI No.: MDI52L07NE00020
Mining Division: Kenora
Area Name: Rex Lake
UTM ZONE: 15
Claim Map No.: G-2637
LOCATION AND ACCESS:
Bug Lake is only accessible by floatplane. The occurrence is located at the extreme north end of the lake
where several large trenches have been developed on a large, relatively flat outcrop.
EXPLORATION HISTORY:
1958-- 1961: Prospectors working for Steep Rock Iron Mines Ltd. discovered copper mineralization at Bug
Lake.
1962-- 1963: Steep Rock Iron Mines Ltd. conducted geological mapping, trenching, stripping, sampling and
magnetic, electromagnetic and self potential ground geophysical surveys over numerous copper occurrences
located north and southeast of Bug Lake.
1964: The Bug Lake property was optioned (Fletcher Lake option) by Rio Tinto Canadian Exploration Ltd.
who conducted induced polarization ground geophysical surveys and diamond drilled 15 holes totalling 2955.5
feet. These holes were drilled on various targets north of Bug Lake. Numerous mineralized sections were intersected in the diamond drilling including: 0.61% Cu across 11.5 feet; 1.37% Cu across 17.7 feet; 2.09% Cu
across 7.7 feet; and 1.44% Cu across 22.5 feet. Two diamond-drill holes totalling 555 feet were also completed on 2 copper occurrences southeast of Bug Lake.
1985-- 1988: Noranda Exploration Ltd. acquired the Bug Lake property and conducted geological mapping,
lithogeochemical surveys and magnetic and electromagnetic ground geophysical surveys. Samples taken from
the trenches by Noranda analysed up to 12% Cu from grab samples and 1.98% Cu across 17 feet from chip
samples.
1992-- 1995: Staked by W. Ferreira and optioned to Canmine Resources Corporation who conducted linecutting; geological mapping; airborne and ground geophysical surveys; and diamond drilling. Canmine referred
to the Bug Lake property as the “Pen property”. Mineralized intersections in 3 holes, diamond drilled in April
1995, analyzed as follows: 1.08% Cu across 31.99 feet (DDH No. 1); 0.86% Cu across 40.15 feet (DDH No.
2); and 1.32% Cu across 16.93 feet (Canmine Resources Corp., Press Release No. A15/95, April 24, 1995).
The diamond-drill holes also intersected low grade molybdenum (0.18% Mo) associated with the copper mineralization. Canmine announced a 25 000-foot diamond-drill program for the Pen property in May, 1995.
GEOLOGICAL DESCRIPTION:
Province: Superior
Subprovince: English River
Metamorphism: 1) Type: Regional
2) Grade: Granulite
Assemblage: English River
The Bug Lake occurrence is situated along a north-northwest-striking fault splay that extends south from the
Werner-- Rex lakes fault at Rex Lake and continues along the east margin of the granodioritic Gone Lake pluton
at Bug Lake. The majority of copper occurrences at Bug Lake are hosted within a thin (< 150 m) discontinuous, arcuate unit of mafic gneiss that extends for approximately 8 km along the Werner-- Rex lakes fault from
Rex Lake to Bug Lake. Small, discontinuous, amphibolitized ultramafic pods and lenses of leucogabbro-anorthosite are closely associated with the mafic gneiss. The mafic gneiss and anorthosite are situated along the
contact of the Gone Lake pluton to the east. The mafic gneiss is in contact with metasedimentary migmatite to
the west. A strong foliation strikes north to north-northwest and dips moderately to the east. An east-striking,
vertical to north-dipping, axial planar S2 foliation is associated with gentle open folding.
The Bug Lake occurrence consists of mafic gneiss intruded by north-striking gabbro dikes and granitic pegmatite dikes. Copper sulphide mineralization is hosted by mafic gneiss and pegmatite.
LITHOLOGIC DESCRIPTION:
The mafic gneiss consists of a fine-grained; massive to weakly foliated; biotite-amphibole-orthopyroxene-plagioclase rock with 10% disseminated magnetite and less than 10% leucosome. The fine-grained gneiss is
gradational with medium- to coarse-grained; moderately to strongly foliated biotite-amphibole- orthopyroxeneplagioclase mafic gneiss. The foliation in the gneiss strikes due north and dips 480 to the east and is folded by
164
a second east-striking foliation that is axial planar to gentle open folding in the gneisses. The mafic gneiss
exhibits gradational layering where dark green-black amphibole-rich layers alternate with white-grey feldsparrich layers; and fine-grained layers alternate with medium- to coarse-grained layers. The coarser grained mafic gneiss contains less than 5% cordierite and garnet porphyroblasts and less than 10% leucosome. the gneiss
is intruded by numerous pegmatite dikes.
A single outcrop of an unusual massive, dark grey, fine- to medium-grained apatite-feldspar-biotite-cordieritehercynite rock is located west of the trenches at the occurrence. The rock contains up to 75% hercynite, low
silica (29.87% SiO2), very high alumina (36.47% Al2O3 ) and relatively high phosphorous (1.2% P2O5). The
outcrop has a curious brecciated texture with a large irregular patch of retrograde biotite.
Medium- to coarse-grained; foliation parallel; massive; dark green to brown-green; mafic dikes with mottled
weathered surfaces intrude most rock types. The dikes are commonly boudinaged or folded with narrow chill
margins along contacts.
Medium- to coarse-grained; white to pink weathering; foliation parallel; irregular granitic pegmatite dikes intrude most rock types. The dikes are dominantly composed of feldspar, quartz and biotite.
MINERAL DESCRIPTION:
Sulphide mineralization occurs within a 1 m wide zone striking 3530/380. Abundant chalcopyrite, minor pyrite
and molybdenite are interstitial to silicate minerals in medium- to coarse-grained granitic pegmatite dikes.
Mafic gneiss also hosts minor disseminated chalcopyrite and pyrite. Abundant red hematite staining occurs in
deeply weathered rocks in the mineralized zone.
ALTERATION DESCRIPTION:
There is no significant alteration other than some minor chloritization in the mineralized mafic gneiss.
MINERALIZED ZONE:
Name: North lakeshore zone Thickness: 1 m Strike: 0030 Dip: 380
Shape: Irregular Character: Disseminated
Classification: Hydrothermal, remobilized
ASSESSMENT FILES (Kenora Resident Geologist office):
52L07NE G-1, G-2, H-1, O-1, O-2
ASSAYS:
Sample
No.
Rock
Name
Cu
(ppm)
Ni
(ppm)
Co
(ppm)
Cr
(ppm)
Mo
(ppm)
Au
(ppb)
Ag
(ppm)
93JRP-- 61
granitic
pegmatite
99850
204
102
90
10.4
550
19.0
165
2. DEPOSIT NAME: NORTH OCCURRENCE
COMMODITIES: Cu, Ni, Ag, Mo
UTM COORDINATES: 385780.0 mE, 5589450.0 mN
UTM Datum: NAD27
MDI No.: MDI52L07NE00023
Mining Division: Kenora
Area Name: Rex Lake
UTM ZONE: 15
Claim Map No.: G-2637
LOCATION AND ACCESS:
Bug Lake is only accessible by floatplane. The North occurrence is located approximately 1.6 km due north of
Bug Lake. Four large trenches are located along the west side of a large, continuous, north-striking outcrop
ridge that can be followed from the north shore of Bug Lake. A low, linear gully extends almost continuously
along the west side of the ridge.
EXPLORATION HISTORY:
1958-- 1961: Prospectors working for Steep Rock Iron Mines Ltd. discovered copper mineralization at Bug
Lake.
1962-- 1963: Steep Rock Iron Mines Ltd. conducted geological mapping, trenching, stripping, sampling and
magnetic, electromagnetic and self potential ground geophysical surveys.
1964: The Bug Lake property was optioned (Fletcher Lake option) by Rio Tinto Canadian Exploration Ltd.
who conducted induced polarization ground geophysical surveys and diamond drilled 15 holes totalling 2955.5
feet. These holes were drilled on various targets north of Bug Lake. Two diamond-drill holes totalling 555
feet were also completed on 2 copper occurrences southeast of Bug Lake. Numerous mineralized sections
were intersected in the diamond drilling including: 0.61% Cu across 11.5 feet; 1.37% Cu across 17.7 feet;
2.09% Cu across 7.7 feet; and 1.44% Cu across 22.5 feet.
1985-- 1988: Noranda Exploration Ltd. acquired the Bug Lake property and conducted geological mapping,
lithogeochemical surveys and magnetic and electromagnetic ground geophysical surveys. Samples taken from
the trenches by Noranda analysed up to 12% Cu from grab samples and 1.98% Cu across 17 feet from chip
samples.
1992-- 1995: Staked by W. Ferreira and optioned to Canmine Resources Corporation who conducted linecutting; geological mapping; airborne and ground geophysical surveys; and diamond drilling. Canmine referred
to the Bug Lake property as the “Pen property”. Mineralized intersections in 3 holes, diamond drilled in April
1995, analyzed as follows: 1.08% Cu across 31.99 feet (DDH No. 1); 0.86% Cu across 40.15 feet (DDH No.
2); and 1.32% Cu across 16.93 feet (Canmine Resources Corp., Press Release No. A15/95, April 24, 1995).
The diamond-drill holes also intersected low grade molybdenum (0.18% Mo) associated with the copper mineralization. Canmine announced a 25 000-foot diamond-drill program for the Pen property in May, 1995.
GEOLOGICAL DESCRIPTION:
Province: Superior
Subprovince: English River
Metamorphism: 1) Type: Regional
2) Grade: Granulite
Assemblage: English River
The North occurrence is situated along a north-northwest-striking fault splay that extends south from the Werner-- Rex lakes fault at Rex Lake and continues along the east margin of the granodioritic Gone Lake pluton at
Bug Lake. The majority of copper occurrences are hosted within a thin (< 150 m) discontinuous, arcuate unit
of mafic gneiss that extends for approximately 8 km along the Werner-- Rex lakes fault from Rex Lake to Bug
Lake. Small, discontinuous, amphibolitized ultramafic pods and lenses of leucogabbro-anorthosite are closely
associated with the mafic gneiss. The mafic gneiss and anorthosite are situated along the contact of the Gone
Lake pluton to the east. The mafic gneiss is in contact with metasedimentary migmatite to the west. A strong
foliation strikes north to north-northwest and dips moderately to the east. An east-striking, vertical to northdipping, axial planar S2 foliation is associated with gentle open folding.
The North occurrence consists of discontinuous lenses of altered ultramafic rocks; orthopyroxene-cordierite
rocks; and mafic gneiss within diatexitic metasedimentary migmatite. Copper sulphide mineralization is
hosted by the ultramafic rocks and mafic gneiss.
LITHOLOGIC DESCRIPTION:
Most lithologies are moderately to strongly foliated. The foliation strikes north or north-northwest and dips
moderately to the east and is folded by a second east-striking foliation that is axial planar to gentle open folding in the gneisses. Z-drag folds were observed in some rock units.
166
The mafic gneiss occurs in narrow, moderately to strongly foliated discontinuous lenses. It consists of medium- to coarse-grained, granoblastic to gneissic rocks composed of variable amounts of plagioclase + magnetite + amphibole + orthopyroxene + biotite + quartz. The gneiss is rusty orange-brown to buff grey-brown on
weathered surfaces with a colour index ranging from 20 to 50. The mafic gneiss is weakly to strongly porphyroblastic and contains orthopyroxene, garnet and cordierite. It contains up to 50% garnet and abundant epidote
pods and veins.
The migmatite is a massive to strongly foliated, medium- to coarse-grained, inhomogeneous diatexitic metasedimentary migmatite consisting of pink-white weathering granitoid and pegmatoid material with 10 to 40 %
strongly foliated wacke and pelitic paleosome. The paleosome consists of alternating pelitic and quartz-feldspar-rich layers and contains 5 to 50% garnet porphyroblasts. The migmatite is strongly deformed and contorted and intruded by numerous pegmatoid and granitoid dikes. The migmatite is commonly interlayered with
narrow layers of amphibole. Elliptical ultramafic pods less than 0.5 m in size are scattered throughout the
migmatite. The pods have well developed, symmetrical reaction rims that consist of an outer rim of black biotite; an interior rim composed of amphibole; and a core of fibrous, green actinolite.
Ultramafic rocks at the North occurrence consist of small (2.4 m wide) irregular lenses of strongly foliated;
medium- to coarse-grained; black to dark green; biotite-amphibole + garnet schist. Layers of coarse biotite
alternate with fine-grained, amphibole-rich layers with gradational contacts. The schists are intruded by numerous granitic pegmatite dikes. The ultramafic pods have been modified by serpentinization, replacement,
recrystallization and several periods of metasomatism and metamorphism associated with the intrusion of granitic and pegmatitic rocks. The altered ultramafic rocks are almost completely composed of metamorphic amphibole (actinolite-tremolite, hornblende) and secondary magnetite with variable amounts of chlorite, clinochlore, clinozoisite, biotite, phlogopite and hercynite (dark green iron spinel).
Massive, medium- to coarse-grained orthopyroxene-cordierite rocks occur in discontinuous lenses and consist
of coarse orthopyroxene + cordierite + biotite + plagioclase + magnetite + garnet. These rocks are distributed
along the west side of the steep outcrop and are exposed in trenches. A narrow garnetiferous section of orthopyroxene-cordierite rock extends along its contact with mafic gneiss and migmatite.
Medium- to coarse-grained, white to pink weathering, irregular granitic pegmatoid dikes dominantly composed
of feldspar, quartz and biotite intrude all rock types.
MINERAL DESCRIPTION:
Sulphide mineralization occurs within narrow (1 m), discontinuous, north-striking and moderately east-dipping
zones in altered and strongly foliated ultramafic rocks and massive orthopyroxene-cordierite rocks. Chalcopyrite (3 to 20%), pyrite and minor molybdenite (2%) commonly occur in foliation parallel seams and veins that
are generally less than 1 cm thick. Some of the sulphide veins also transect the foliation. The sulphide minerals are erratically disseminated throughout the host rocks and are interstitial to silicate minerals. Less than 1 to
3% disseminated pyrite and chalcopyrite also occurs in garnetiferous mafic gneiss and migmatite. Some red
hematite staining was observed in the mineralized zones.
The North occurrence consists of 4 trenches sunk at 30 m intervals along a north-northwest strike. The best
mineralization occurs in the 2 most northerly trenches.
ALTERATION DESCRIPTION:
Host rocks are weakly to moderately altered adjacent to sulphide seams and veins. Narrow, chloritic alteration
halos extend for 1 to 5 cm on either side of the veins. The alteration halos may also contain clinozoisite.
Dense, aggregates of fibrous amphibole are commonly perpendicular to the edges of the sulphide veins and are
intergrown with the sulphide minerals.
MINERALIZED ZONE:
Name: North zone Thickness: 1 m Strike: 3500 Dip: 680
Shape: Irregular Character: Disseminated, vein
Classification: Hydrothermal, remobilized
ASSESSMENT FILES (Kenora Resident Geologist office):
52L07NE G-1, G-2, H-1, O-1, O-2
167
ASSAYS:
Sample No.
Rock
Name
Cu
(ppm)
Ni
(ppm)
Co
(ppm)
Cr
(ppm)
Mo
(ppm)
Au
(ppb)
Ag
(ppm)
93JRP-- 68
u/m
98240
1304
266
44
650
568
22.0
93JRP-- 69
u/m
25810
814
143
31
473
244
10
93JRP-- 97
u/m
71270
1164
188
149
742
304
12
93JRP-- 100
u/m
14980
414
117
98
153
245
5
93JRP-- 101
u/m
7381
138
211
185
11.9
169
3
93JRP-- 102
bt-grt-opx 12330
84.2
213
76
17
320
4
m gneiss
Abbreviations: bt – biotite; grt – garnet; opx – orthopyroxene; m gneiss – mafic gneiss; u/m –
ultramafic rock
168
3. DEPOSIT NAME: PERKINS OCCURRENCE
COMMODITIES: Cu
UTM COORDINATES: 385840.0 mE, 5589000.0 mN
UTM Datum: NAD27
MDI No.: MDI52L07NE00024
Mining Division: Kenora
Area Name: Rex Lake
UTM ZONE: 15
Claim Map No.: G-2637
LOCATION AND ACCESS:
Bug Lake is only accessible by floatplane. The South trenches at the Perkins occurrence are located approximately 820 m due north of Bug Lake while the North trenches are located about 1 km north of the lake. The
trenches are situated along the west side of a large, continuous, north-striking outcrop ridge that can be followed from the north shore of Bug Lake. A low, linear gully extends almost continuously along the west side
of the ridge.
EXPLORATION HISTORY:
1958-- 1961: Prospectors working for Steep Rock Iron Mines Ltd. discovered copper mineralization at Bug
Lake.
1962-- 1963: Steep Rock Iron Mines Ltd. conducted geological mapping, trenching, stripping, sampling and
magnetic, electromagnetic and self potential ground geophysical surveys.
1964: The Bug Lake property was optioned (Fletcher Lake option) by Rio Tinto Canadian Exploration Ltd.
who conducted induced polarization ground geophysical surveys and diamond drilled 15 holes totalling 2955.5
feet. These holes were drilled on various targets north of Bug Lake. Two diamond-drill holes totalling 555
feet were also completed on 2 copper occurrences southeast of Bug Lake. Numerous mineralized sections
were intersected in the diamond drilling including: 0.61% Cu across 11.5 feet; 1.37% Cu across 17.7 feet;
2.09% Cu across 7.7 feet; and 1.44% Cu across 22.5 feet.
1985-- 1988: Noranda Exploration Ltd. acquired the Bug Lake property and conducted geological mapping,
lithogeochemical surveys and magnetic and electromagnetic ground geophysical surveys. Samples taken from
the trenches by Noranda analysed up to 12% Cu from grab samples and 1.98% Cu across 17 feet from chip
samples.
1992-- 1995: Staked by W. Ferreira and optioned to Canmine Resources Corporation who conducted linecutting; geological mapping; airborne and ground geophysical surveys; and diamond drilling. Canmine referred
to the Bug Lake property as the “Pen property”. Mineralized intersections in 3 holes, diamond drilled in April
1995, analyzed as follows: 1.08% Cu across 31.99 feet (DDH No. 1); 0.86% Cu across 40.15 feet (DDH No.
2); and 1.32% Cu across 16.93 feet (Canmine Resources Corp., Press Release No. A15/95, April 24, 1995).
The diamond-drill holes also intersected low grade molybdenum (0.18% Mo) associated with the copper mineralization. Canmine announced a 25 000-foot diamond-drill program for the Pen property in May, 1995.
GEOLOGICAL DESCRIPTION:
Province: Superior
Subprovince: English River
Metamorphism: 1) Type: Regional
2) Grade: Granulite
Assemblage: English River
The Perkins occurrence is situated along a north-northwest-striking fault splay that extends south from the
Werner-- Rex lakes fault at Rex Lake and continues along the east margin of the granodioritic Gone Lake pluton
at Bug Lake. The majority of copper occurrences at Bug Lake are hosted within a thin (< 150 m) discontinuous, arcuate unit of mafic gneiss that extends for approximately 8 km along the Werner-- Rex lakes fault from
Rex Lake to Bug Lake. Small, discontinuous, amphibolitized ultramafic pods and lenses of leucogabbro-anorthosite are closely associated with the mafic gneiss. The mafic gneiss and anorthosite are situated along the
contact of the Gone Lake pluton to the east. The mafic gneiss is in contact with metasedimentary migmatite to
the west. A strong foliation strikes north to north-northwest and dips moderately to the east. An east-striking,
vertical to north-dipping, axial planar S2 foliation is associated with gentle open folding.
The Perkins occurrence consists of mafic gneiss and orthopyroxene-cordierite rocks intruded by north-striking
granitic pegmatite dikes.
LITHOLOGIC DESCRIPTION:
North Trenches
The majority of lithologies at the North trenches are moderately foliated 3500/600. The foliation is folded by a
second east-striking foliation that is axial planar to open folding in the gneisses.
169
Moderately to strongly foliated; fine- to medium-grained; granoblastic to gneissic mafic gneiss is composed of
variable amounts of plagioclase + magnetite + amphibole + orthopyroxene + biotite + quartz. The gneiss is
rusty orange-brown to buff grey-brown on weathered surfaces and contains about 35% mafic minerals and 20%
garnet porphyroblasts less than 1 cm in size.
Massive, fine- to very coarse-grained, orthopyroxene-cordierite rocks occur in discontinuous, irregular lenses
and consist of coarse orthopyroxene + cordierite + biotite + plagioclase + magnetite + garnet. These rocks are
distributed along the west side of the outcrop and are exposed in trenches. Garnet porphyroblasts range in size
from 0.5 cm to 4 cm and make up 30 to 50% of the rock. The rock also contains local concentrations of cordierite up to 60% and large orthopyroxene crystals up to 2 cm in size.
A finer grained, moderately to strongly foliated, orthopyroxene-cordierite rock contains 5 to 10% quartz; less
than 15% cordierite; 10% fine-grained magnetite; and narrow stringers of quartz-feldspar-orthopyroxene-magnetite leucosome. This finer grained rock has gradational contacts with the mafic gneiss.
Coarse-grained; white to pink weathering; irregular; discontinuous; foliation parallel; granitic pegmatite dikes
are dominantly composed of feldspar and quartz and intrude most rock types.
South Trenches
Lithologies at the South trenches are identical or similar to those at the North trenches. The orthopyroxenecordierite rocks contain variable amounts of garnet (5 to 50%) and thick accumulations of cordierite that appear to be cordierite veins. The foliation varies from 0300/67 to 3450/730 and affects most lithologies with the
exception of some very massive orthopyroxene-cordierite rocks.
MINERAL DESCRIPTION:
North Trenches
Sulphide mineralization consists of 2 to 5% disseminated chalcopyrite and pyrite in mafic gneiss and coarsegrained orthopyroxene-cordierite rocks. A quartz vein contains some minor disseminated chalcopyrite. The
North trenches consist of one 20 m long, shallow, east-striking trench and several small test pits.
A trench has also been sunk on a large enclave of mafic gneiss enclosed within pegmatitic granodioritic rocks
of the Gone Lake pluton. This trench is located on a steep outcrop across the gully from the other trenches.
About 3 to 15% chalcopyrite and pyrite are disseminated along foliation planes in the mafic gneiss and are
interstitial to silicate minerals in pegmatite dikes that intrude the gneiss. One grab sample was taken at this
trench (93JRP-- 79).
South Trenches
Sulphide mineralization consists of 5 to 10% disseminated chalcopyrite, pyrite and minor molybdenite disseminated throughout massive, coarse-grained, orthopyroxene-cordierite rocks. Sulphide minerals are also hosted
by granitic pegmatite dikes. Some narrow, foliation parallel, sulphide veins, containing up to 30% chalcopyrite, were found in moderately foliated orthopyroxene-garnet-cordierite rocks. Some semi-massive sulphide
minerals have a well developed, strong, protomylonite or “ball-texture” consisting of rounded fragments of
wall rock embedded in a fine-grained groundmass of chalcopyrite and pyrite. This texture is indicative of
faulting and solid state remobilization of the sulphide minerals.
The South trenches consist of 3 long, east-striking trenches that are 18 to 29 m apart along a north strike.
ALTERATION DESCRIPTION:
There is no significant alteration other than some chloritization in the mineralized rocks.
MINERALIZED ZONE:
Name: Perkins Thickness: 1 to 3 m Strike: north-northwest Dip: 500
Shape: Irregular Character: Disseminated
Classification: Hydrothermal, remobilized
ASSESSMENT FILES (Kenora Resident Geologist office):
52L07NE G-1, G-2, H-1, O-1, O-2
170
ASSAYS:
North Trenches
Sample
No.
Rock
Name
Cu
(ppm)
Ni
(ppm)
Co
(ppm)
Cr
(ppm)
Mo
(ppm)
Au
(ppb)
Ag
(ppm)
93JRP-- 65
grt-crd-bt-f
el-opx gn
8.05
223
47.9
499
<6
<3
<2
93JRP-- 67
bt-opx-grt-f
el-qtz gn
14.97
118
34
211
<6
<3
**
93JRP-- 78 grt-bt-opx-q
tz-fel gn
10.8
247
47.9
515
<6
<3
<2
44600
160
38.5
18
6.46
697
12
93JRP-- 79
granitic
pegmatite
South Trenches
Sample No.
Rock
Name
Cu
(ppm)
Ni
(ppm)
Co
(ppm)
Cr
(ppm)
Mo
(ppm)
Au
(ppb)
Ag
(ppm)
93JRP-- 71
grt-bt-opx
m gneiss
1510
228
104
281
<6
<3
<2
93JRP-- 73
grt-bt-opx
m gneiss
5548
88.7
132
351
6.21
49
2
93JRP-- 74
grt-bt-opx
m gneiss
7866
176
70.4
310
<6
61
3
93JRP-- 75
granitic
123900
451
298
389
36.2
180
16
pegmatite
Abbreviations: bt – biotite; crd – cordierite; fel – feldspar; grt – garnet; opx – orthopyroxene;
qtz – quartz; m gneiss – mafic gneiss
171
4. DEPOSIT NAME: SOUTH OCCURRENCES
COMMODITIES: Cu
UTM COORDINATES: 386400.0 mE, 5586900.0 mN
UTM Datum: NAD27
MDI No.: 52L07NE
Mining Division: Kenora
Area Name: Rex Lake
UTM ZONE: 15
Claim Map No.: G-2637
LOCATION AND ACCESS:
Bug Lake is only accessible by floatplane. The South occurrences consist of 10 separate trenches, generally
about 30 m apart, that extend southeast from Bug Lake along a strike length of about 1.2 km. The first trench
is located on the east shore of a narrow bay, at the southeast corner of Bug Lake. The other trenches are distributed along the southwest side of a narrow, outcrop ridge that extends southeast from Bug Lake. A narrow,
linear, gully extends continuously along the southwest side of the ridge.
EXPLORATION HISTORY:
1958-- 1961: Prospectors working for Steep Rock Iron Mines Ltd. discovered copper mineralization at Bug
Lake.
1962-- 1963: Steep Rock Iron Mines Ltd. conducted geological mapping, trenching, stripping, sampling and
magnetic, electromagnetic and self potential ground geophysical surveys.
1964: The Bug Lake property was optioned (Fletcher Lake option) by Rio Tinto Canadian Exploration Ltd.
who conducted induced polarization ground geophysical surveys and diamond drilled 15 holes totalling 2955.5
feet. These holes were drilled on various targets north of Bug Lake. Two diamond-drill holes totalling 555
feet were also completed on 2 copper occurrences southeast of Bug Lake. Numerous mineralized sections
were intersected in the diamond drilling including: 0.61% Cu across 11.5 feet; 1.37% Cu across 17.7 feet;
2.09% Cu across 7.7 feet; and 1.44% Cu across 22.5 feet.
1985-- 1988: Noranda Exploration Ltd. acquired the Bug Lake property and conducted geological mapping,
lithogeochemical surveys and magnetic and electromagnetic ground geophysical surveys. Samples taken from
the trenches by Noranda analysed up to 12% Cu from grab samples and 1.98% Cu across 17 feet from chip
samples.
1992-- 1995: Staked by W. Ferreira and optioned to Canmine Resources Corporation who conducted linecutting; geological mapping; airborne and ground geophysical surveys; and diamond drilling. Canmine referred
to the Bug Lake property as the “Pen property”. Mineralized intersections in 3 holes, diamond drilled in April
1995, analyzed as follows: 1.08% Cu across 31.99 feet (DDH No. 1); 0.86% Cu across 40.15 feet (DDH No.
2); and 1.32% Cu across 16.93 feet (Canmine Resources Corp., Press Release No. A15/95, April 24, 1995).
The diamond-drill holes also intersected low grade molybdenum (0.18% Mo) associated with the copper mineralization. Canmine announced a 25 000-foot diamond-drill program for the Pen property in May, 1995.
GEOLOGICAL DESCRIPTION:
Province: Superior
Subprovince: English River
Metamorphism: 1) Type: Regional
2) Grade: Granulite
Assemblage: English River
The South occurrences are situated along a north-northwest-striking fault splay that extends south from the
Werner-- Rex lakes fault at Rex Lake and continues along the east margin of the granodioritic Gone Lake pluton
at Bug Lake. The majority of copper occurrences are hosted within a thin (< 150 m) discontinuous, arcuate
unit of mafic gneiss that extends for approximately 8 km along the Werner-- Rex lakes fault from Rex Lake to
Bug Lake. Small, discontinuous, amphibolitized ultramafic pods and lenses of leucogabbro-anorthosite are
closely associated with the mafic gneiss. The mafic gneiss and anorthosite are situated along the contact of the
Gone Lake pluton to the east. The mafic gneiss is in contact with metasedimentary migmatite to the west. A
strong foliation strikes north to north-northwest and dips moderately to the east. An east-striking, vertical to
north-dipping, axial planar S2 foliation is associated with gentle open folding.
The South occurrences consist of mafic gneiss and metasedimentary migmatite interlayered with discontinuous
lenses of amphibole-biotite schist and orthopyroxene-cordierite rock. Copper sulphide mineralization is hosted
by mafic gneiss and amphibole-biotite schist.
LITHOLOGIC DESCRIPTION:
The majority of rocks southeast of Bug Lake are very strongly deformed and commonly mylonitic in several
locations. Z-drag folding is common in the metasedimentary migmatite as well as boudinaged pegmatitic
dikes and quartz veins.
172
Mafic gneiss consists of medium- to coarse-grained, granoblastic to gneissic rocks composed of variable
amounts of plagioclase + magnetite + amphibole + orthopyroxene + biotite + quartz. The gneiss is rusty
orange-brown to buff grey-brown on weathered surfaces with strong hematite and limonite staining and a
colour index ranging from 20 to 50. The mafic gneiss is weakly to strongly porphyroblastic and contains variable amounts of orthopyroxene, garnet and cordierite. The mafic gneiss contains up to 50 or 90 % cordierite or
garnet and hosts irregular and discontinuous patches of cordierite + plagioclase + biotite + orthopyroxene +
garnet leucosome. The mafic gneiss contains 0-10% leucosome, which is typical of mafic rocks in areas of
high-grade metamorphism. Cordierite occurs in narrow (<1 m) foliation parallel layers; in fine- to mediumgrained, patchy aggregates; or as large (< 1 to 4 cm) subhedral, indigo-blue crystals disseminated throughout
the mafic gneiss.
The migmatite is strongly foliated, medium- to coarse-grained, inhomogeneous diatexitic metasedimentary
migmatite consisting of pink-white weathering granitoid and pegmatoid material with 10 to 40 % strongly foliated wacke and pelitic paleosome. The paleosome consists of alternating pelitic and quartz-feldspar-rich layers and contains 5 to 50% garnet porphyroblasts. The migmatite is strongly deformed and contorted and intruded by numerous boudinaged pegmatoid and granitoid dikes. The migmatite is commonly interlayered with
narrow, orthopyroxene + cordierite layers. Elliptical ultramafic pods less than 0.5 m in size are scattered
throughout the migmatite. The pods have well developed, symmetrical reaction rims that consist of an outer
rim of black biotite; an interior rim composed of amphibole; and a core of fibrous, green actinolite.
Massive, medium- to coarse-grained orthopyroxene-cordierite rocks occur in discontinuous lenses and consist
of coarse orthopyroxene + cordierite + biotite + plagioclase + magnetite. Biotite-amphibole schist occurs in
small pods, lenses and seams that are interlayered with mafic gneiss and migmatite. Leucogabbro is coarsegrained and composed of large, white, recrystallized plagioclase crystals; coarse black amphibole; biotite and
orthopyroxene. The leucogabbro is variably epidotized with epidote on fractures; in veins; and in small pods
and clots. The leucogabbro is intruded by granodioritic rocks of the Gone Lake pluton.
Medium- to coarse-grained; white to pink weathering; foliation parallel granitic pegmatite dikes are dominantly composed of feldspar, quartz and biotite and intrude migmatite and mafic gneiss. The pegmatitic dikes and
associated quartz veins are strongly deformed and boudinaged parallel to foliation.
MINERAL DESCRIPTION:
The sulphide mineralization, in the majority of trenches, consists of less than 1 to 10% chalcopyrite; 1 to 3%
pyrite; and less than 1% molybdenite. Sulphide minerals are disseminated along foliation planes but may also
occur in narrow, foliation parallel, sulphide veins up to 6 cm wide. The majority of the sulphide mineralization is hosted by mafic gneiss and narrow (1 m wide) lenses of amphibole-biotite schist. Mafic gneiss also
hosts minor disseminated chalcopyrite and pyrite. Abundant red hematite and limonite staining occurs on most
mineralized outcrops. About 10% magnetite is disseminated throughout the mafic gneiss but it also occurs in
numerous, crisscrossing, 0.5 to 1.5 cm wide extension magnetite veins that transect the foliation.
ALTERATION DESCRIPTION:
There is no significant alteration other than some minor chloritization in the mineralized mafic gneiss and amphibole-biotite schist.
MINERALIZED ZONE:
Name: South zone Thickness: 1 m Strike: 3100 Dip: 500
Shape: Irregular Character: Disseminated, veins
Classification: Hydrothermal, remobilized
ASSESSMENT FILES (Kenora Resident Geologist office):
52L07NE G-1, G-2, H-1, O-1, O-2
173
ASSAYS:
Sample No. Rock Name
Cu
(ppm)
Ni
(ppm)
Co
(ppm)
Cr
(ppm)
Mo
(ppm)
Au
(ppb)
Ag
(ppm)
93JRP-- 62
biotitic u/m
rock
3189
246
79.9
242
9.83
39
2
93JRP-- 104
granitic
pegmatite
9214
169
55.3
35
12.6
146
3
93JRP-- 105
bt-opx-fel
m gneiss
10050
189
67.8
108
11.9
165
2
93JRP-- 107
pegmatoid
leucosome
8359
330
41
95
12.1
340
4
93JRP-- 108
bt-opx-fel
m gneiss
51950
399
162
148
24.8
535
7
93JRP-- 109
bt-opx-fel
m gneiss
2980
121
41.4
104
<6
39
2
93JRP-- 110
bt-opx-qtz
mm
2082
208
85.3
447
10.5
30
<2
93JRP-- 111
opx-qtz-fel
leucosome
1723
92.3
41.1
89
<6
27
<2
93JRP-- 112
bt-opx-fel
m gneiss
6894
208
66.6
121
<6
91
2
93JRP-- 114
m gneiss
744.3
103
66.8
73
<6
3
2
Abbreviations: bt – biotite; fel – feldspar; opx – orthopyroxene; qtz – quartz;
m gneiss – mafic gneiss; mm – metasedimentary migmatite; u/m – ultramafic
174
5. DEPOSIT NAME: STEEP ROCK OCCURRENCES
COMMODITIES: Cu
UTM COORDINATES: 385850.0 mE, 5588300.0 mN
UTM Datum: NAD27
MDI No.: 52L07NE
Mining Division: Kenora
Area Name: Rex Lake
UTM ZONE: 15
Claim Map No.: G-2637
LOCATION AND ACCESS:
Bug Lake is only accessible by floatplane. The Steep Rock trenches are located approximately 320 m due
north of Bug Lake. There are approximately 10 trenches and test pits situated along the east and west sides of
a large, continuous, north-striking outcrop ridge that can be followed from the north shore of Bug Lake. A
low, linear gully extends almost continuously along both sides of the ridge.
EXPLORATION HISTORY:
1958-- 1961: Prospectors working for Steep Rock Iron Mines Ltd. discovered copper mineralization at Bug
Lake.
1962-- 1963: Steep Rock Iron Mines Ltd. conducted geological mapping, trenching, stripping, sampling and
magnetic, electromagnetic and self potential ground geophysical surveys.
1964: The Bug Lake property was optioned (Fletcher Lake option) by Rio Tinto Canadian Exploration Ltd.
who conducted induced polarization ground geophysical surveys and diamond drilled 15 holes totalling 2955.5
feet. These holes were drilled on various targets north of Bug Lake. Two diamond-drill holes totalling 555
feet were also completed on 2 copper occurrences southeast of Bug Lake. Numerous mineralized sections
were intersected in the diamond drilling including: 0.61% Cu across 11.5 feet; 1.37% Cu across 17.7 feet;
2.09% Cu across 7.7 feet; and 1.44% Cu across 22.5 feet.
1985-- 1988: Noranda Exploration Ltd. acquired the Bug Lake property and conducted geological mapping,
lithogeochemical surveys and magnetic and electromagnetic ground geophysical surveys. Samples taken from
the trenches by Noranda analysed up to 12% Cu from grab samples and 1.98% Cu across 17 feet from chip
samples.
1992-- 1995: Staked by W. Ferreira and optioned to Canmine Resources Corporation who conducted linecutting; geological mapping; airborne and ground geophysical surveys; and diamond drilling. Canmine referred
to the Bug Lake property as the “Pen property”. Mineralized intersections in 3 holes, diamond drilled in April
1995, analyzed as follows: 1.08% Cu across 31.99 feet (DDH No. 1); 0.86% Cu across 40.15 feet (DDH No.
2); and 1.32% Cu across 16.93 feet (Canmine Resources Corp., Press Release No. A15/95, April 24, 1995).
The diamond-drill holes also intersected low grade molybdenum (0.18% Mo) associated with the copper mineralization. Canmine announced a 25 000-foot diamond-drill program for the Pen property in May, 1995.
GEOLOGICAL DESCRIPTION:
Province: Superior
Subprovince: English River
Metamorphism: 1) Type: Regional
2) Grade: Granulite
Assemblage: English River
The Steep Rock occurrences are situated along a north-northwest-striking fault splay that extends south from
the Werner-- Rex lakes fault at Rex Lake and continues along the east margin of the granodioritic Gone Lake
pluton at Bug Lake. The majority of copper occurrences at Bug Lake are hosted within a thin (< 150 m) discontinuous, arcuate unit of mafic gneiss that extends for approximately 8 km along the Werner-- Rex lakes fault
from Rex Lake to Bug Lake. Small, discontinuous, amphibolitized ultramafic pods and lenses of leucogabbroanorthosite are closely associated with the mafic gneiss. The mafic gneiss and anorthosite are situated along
the contact of the Gone Lake pluton to the east. The mafic gneiss is in contact with metasedimentary migmatite to the west. A strong foliation strikes north to north-northwest and dips moderately to the east. An eaststriking, vertical to north-dipping, axial planar S2 foliation is associated with gentle open folding.
The Steep Rock occurrences consist of mafic gneiss, metasedimentary migmatite and orthopyroxene-cordierite
rock intruded by north-striking gabbro dikes and granitic pegmatite dikes. Copper sulphide mineralization is
hosted by mafic gneiss and orthopyroxene-cordierite rock.
LITHOLOGIC DESCRIPTION:
The mafic gneiss consists of a fine-grained; massive to weakly foliated; biotite-amphibole-orthopyroxene- plagioclase rock with 10% disseminated magnetite and less than 10% leucosome. The fine-grained gneiss is
175
gradational with medium- to coarse-grained; moderately to strongly foliated biotite-amphibole-orthopyroxeneplagioclase mafic gneiss. The foliation in the gneiss strikes due north and dips 480 to the east and is folded by
a second east-striking foliation that is axial planar to gentle open folding in the gneisses. The mafic gneiss
exhibits gradational layering where dark green-black amphibole-rich layers alternate with white-grey feldsparrich layers; and fine-grained layers alternate with medium- to coarse-grained layers. The mafic gneiss contains
less than 5 to 60% cordierite and garnet porphyroblasts and less than 10% leucosome. Large patches of cordierite-rich leucosome are common in the mafic gneiss.
The migmatite is a massive to strongly foliated, medium- to coarse-grained, inhomogeneous diatexitic metasedimentary migmatite consisting of pink-white weathering granitoid and pegmatoid material with 10 to 40 %
strongly foliated wacke and pelitic paleosome. The paleosome consists of alternating pelitic and quartz-feldspar-rich layers and contains 5 to 60% garnet porphyroblasts. The migmatite is strongly deformed and contorted and intruded by numerous pegmatoid and granitoid dikes.
Massive, medium- to very coarse-grained, orthopyroxene-cordierite rocks occur in discontinuous, irregular
lenses and consist of coarse orthopyroxene + cordierite + biotite + plagioclase + magnetite + garnet. The rock
also contains local concentrations of cordierite up to 60% and large orthopyroxene crystals up to 2 cm in size.
Medium- to coarse-grained; foliation parallel; massive; dark green to brown-green; mafic dikes with mottled
weathered surfaces intrude most rock types. The dikes are commonly boudinaged or folded with narrow chill
margins along contacts.
Medium- to coarse-grained; white to pink weathering; foliation parallel; irregular granitic pegmatite dikes intrude most rock types. The dikes are dominantly composed of feldspar, quartz and biotite.
MINERAL DESCRIPTION:
Sulphide mineralization is generally disseminated within narrow (less than 1 m) zones in mafic gneiss; orthopyroxene-cordierite rocks; and pegmatite dikes. Sulphide mineralization consists of less than 1 to 5% chalcopyrite; 1 to 3% pyrite; and very minor molybdenite. Abundant red hematite staining occurs in deeply weathered rocks in the mineralized zone. The mafic gneiss also hosts about 10 to 15% fine-grained, disseminated
magnetite.
ALTERATION DESCRIPTION:
There is no significant alteration other than some minor chloritization in the mineralized rocks.
MINERALIZED ZONE:
Name: Steep Rock zone Thickness: 1 m Strike: 0030 Dip: 500
Shape: Irregular, discontinuous Character: Disseminated
Classification: Hydrothermal, remobilized
ASSESSMENT FILES (Kenora Resident Geologist office):
52L07NE G-1, G-2, H-1, O-1, O-2
176
ASSAYS:
Sample No.
Rock Name
Cu
(ppm)
Ni
(ppm)
Co
(ppm)
Cr
(ppm)
Mo
(ppm)
Au
(ppb)
Ag
(ppm)
93JRP-- 66
grt-opx-bt-qtzfel gneiss
6670
57.9
109
20
6.04
200
3
93JRP-- 81
opx-qtz-fel
gneiss
3812
36.8
20.6
19
<6
57
2
93JRP-- 82
opx-bt-fel
mafic gneiss
689.3
153
52.3
345
<6
9
2
93JRP-- 83
opx-qtz-fel
gneiss
4244
87.5
117
30
8.59
90
2
93JRP-- 84
pegmatoid
leucosome
1112
57.7
29.3
230
<6
5
<2
93JRP-- 85
opx-qtz-fel
gneiss
278.8
56.6
130
196
<6
<3
<2
Abbreviations: bt – biotite; fel – feldspar; grt – garnet; opx – orthopyroxene; qtz - quartz
177
Metric Conversion Table
Conversion from SI to Imperial
Conversion from Imperial to SI
SI Unit
Multiplied by
Gives
Imperial Unit
1 mm
1 cm
1m
1m
1 km
0.039 37
0.393 70
3.280 84
0.049 709
0.621 371
LENGTH
inches
1 inch
25.4
inches
1 inch
2.54
feet
1 foot
0.304 8
chains
1 chain
20.116 8
miles (statute) 1 mile (statute) 1.609 344
mm
cm
m
m
km
1 cm@
1 m@
1 km@
1 ha
0.155 0
10.763 9
0.386 10
2.471 054
AREA
square inches 1 square inch
square feet
1 square foot
square miles
1 square mile
acres
1 acre
6.451 6
0.092 903 04
2.589 988
0.404 685 6
cm@
m@
km@
ha
1 cm#
1 m#
1 m#
0.061 023
35.314 7
1.307 951
VOLUME
cubic inches
1 cubic inch
cubic feet
1 cubic foot
cubic yards
1 cubic yard
16.387 064
0.028 316 85
0.764 554 86
cm#
m#
m#
CAPACITY
1 pint
1 quart
1 gallon
Multiplied by
1L
1L
1L
1.759 755
0.879 877
0.219 969
pints
quarts
gallons
1g
1g
1 kg
1 kg
1t
1 kg
1t
0.035 273 962
0.032 150 747
2.204 622 6
0.001 102 3
1.102 311 3
0.000 984 21
0.984 206 5
MASS
ounces (avdp) 1 ounce (avdp) 28.349 523
ounces (troy) 1 ounce (troy) 31.103 476 8
pounds (avdp) 1 pound (avdp) 0.453 592 37
tons (short)
1 ton (short)
907.184 74
tons (short)
1 ton (short)
0.907 184 74
tons (long)
1 ton (long)
1016.046 908 8
tons (long)
1 ton (long)
1.016 046 90
1 g/t
0.029 166 6
1 g/t
0.583 333 33
CONCENTRATION
ounce (troy)/
1 ounce (troy)/
ton (short)
ton (short)
pennyweights/ 1 pennyweight/
ton (short)
ton (short)
Gives
0.568 261
1.136 522
4.546 090
L
L
L
g
g
kg
kg
t
kg
t
34.285 714 2
g/t
1.714 285 7
g/t
OTHER USEFUL CONVERSION FACTORS
1 ounce (troy) per ton (short)
1 gram per ton (short)
1 ounce (troy) per ton (short)
1 pennyweight per ton (short)
Multiplied by
31.103 477
grams per ton (short)
0.032 151 ounces (troy) per ton (short)
20.0
pennyweights per ton (short)
0.05
ounces (troy) per ton (short)
Note: Conversion factors which are in bold type are exact. The conversion factors have been taken from or have been
derived from factors given in the Metric Practice Guide for the Canadian Mining and Metallurgical Industries, published by the Mining Association of Canada in co-operation with the Coal Association of Canada.
178
ISSN 0826-9580
ISBN 0-7778-7352-4