Download Graphite - Geological Survey of Ethiopia

GEOLOGICAL SURVER OF ETHIOPIA
GEOSCIECE DATA DIRECTORIATE
GRAPHITE AROUND KIBRE MENGIST AND MOYALE AREA
OROMIA NATIONAL REGIONAL STATE, ETHIOPIA
By:
Degife Shiferaw
DECEMBER 2012
ADDIS ABABA
Opportunities for Graphite development in Ethiopia
Contents
INTRODUCTION .............................................................................................................. 1
Geology ........................................................................................................................... 2
Uses ................................................................................................................................. 3
GRAPHITE IN ETHIOPIA ................................................................................................ 3
Geology of The Study Areas........................................................................................... 4
GRAPHITE OCCURRENCE AROUND KIBRE MENGIST ........................................... 5
Hidi Eda Graphite ........................................................................................................... 6
Kucho Graphite ............................................................................................................... 6
Melka Gonji Graphite ..................................................................................................... 7
Kenticha Graphite ........................................................................................................... 7
Kibre Mengist Graphite .................................................................................................. 7
Moyale Graphite ............................................................................................................. 8
ABOUT THE MINISTRY OF MINES .............................................................................. 8
Mining Legislation .......................................................................................................... 9
Investment Climate of Ethiopia .................................................................................... 10
Mineral Investment ....................................................................................................... 10
REFRENCES .................................................................................................................... 12
Geological Survey of Ethiopia (GSE)
December, 2012
ii
Opportunities for Graphite development in Ethiopia
INTRODUCTION
Graphite is an allotrope of the chemical element carbon and is denoted by the symbol C.
Natural graphite occurs in three distinct forms in nature. Crystalline graphite, amorphous
graphite and lump graphite. Lump graphite, also called vein graphite, is found all over the
world. Graphite is grayish black to steel gray in color and can make impressions on the
substrate. Because of this marking property possessed by graphite, it is used in the
manufacture of pencils and gets its name from the Greek word graphein, which means to
write.Graphite properties make it a unique chemical substance.
Graphite properties
Physical properties of graphite
Following are some of the properties of this compound based on its structure and
occurrence in nature.
Physical state
The mineral graphite is steel gray to black in color and odorless. It is opaque and has a
sub metalic luster. Graphite is very soft and has a greasy texture. It can be broken easily
and leaves a black streak on the hand when touched. Although graphite is soft and
flexible , it is not elastic in nature.
Structure
Graphite is crystalline in nature, however, perfect crystals are rarely found. The carbon
atoms in graphite are arranged in hexagonal manner in planar condensed ring system.
This gives the graphite crystals, a hexagonal shape. Different layers of graphite are
stacked together and held by weak covalent forces, to forms giant covalent structure.
Melting point
Graphite has a high melting point above 3000 degrees centigrade, like that of diamond
,the other allotrope of carbon .Hence ,it is stable over a wide range of temperatures.
Solubility
Graphite is insoluble in water as well as other organic solvents. There are no attractive
forces that occur between the solvent molecules and the carbon atoms in graphite and so
it fails to dissolve in any of the organic solvents.
Geological Survey of Ethiopia (GSE)
December, 2012
1
Opportunities for Graphite development in Ethiopia
Density
As there is a lot of vacant spaces between the graphite sheets, held by the weak covalent
bonds, the density of graphite is 2.09 to 2.33g/cc, which is lower than that of diamond.
The measured specific gravity of graphite is approximately 2.26g/cc, however, it depends
upon the purity of graphite. Graphite with higher ash content shows a specific gravity
higher than 2.26g/cc, while natural graphite has a lower specific gravity or density due to
the trapped porosity.
Electrical conductivity
There is vast delocalization of electrons within the carbon layers of graphite. The
delocalized electrons are free to move and are able to conduct electricity, thus making
graphite a good conductor of electricity.
Chemical properties of graphite
Graphite is chemically inert to almost all chemicals. It burns completely, when heated in
oxygen to form carbondioxide. However, it fails to burn in air, even if it is heated to high
temperatures. When heated in the presence of concentrated sulfuric acid and potassium
dichromate, graphite gets oxidized to carbondioxide. Due to its chemical inertness and
stability at high tempratures, it is widely used as a refractory material.
Geology
Graphite forms during the metamorphism, under intense heat and pressure, of coal or
limestones with a great deal of organic matter in them. Like diamond, the other
crystalline form of carbon, graphite can be manufactured artificially. Graphite is widely
distributed throughout the world. It occurs in many types of igneous, sedimentary, and
metamorphic rocks. Many occurrences are, however, of little economic importance. The
more important are those found in metasomatic-hydrothermal deposits and sedimentary
rocks that have been subjected to regional or thermal metamorphism. Economic deposits
of graphite include five main geological types:

Flake graphite disseminated in metamorphosed, silica-rich sedimentary rocks.

Flake graphite disseminated in marble.
Geological Survey of Ethiopia (GSE)
December, 2012
2
Opportunities for Graphite development in Ethiopia

Amorphous deposits formed by metamorphism of coal or carbon rich sediments.

Veins filling fractures, and cavities in country rock

Contact metasomatic or hydrothermal deposits in metamorphosed, calcareous
sedimentary rocks.
Uses
The followings are some uses of graphite:
Manufacture of lead used in pencils, refractories, steel making, lubricant, making
electrodes, manufacture of polishes and paints, mold in foundary, batteries, bearings, and
brake lining etc.
GRAPHITE IN ETHIOPIA
Graphite occurrence in Ethiopia is known for many years, but significant study was not
carried out except some reconnaissance work at different localities around Kibre Mengist
along with kyanite and talc minerals. Semi detail study was carried out around Moyale.
The study areas around Kibre Mengist and Moyale are in general located in figure1
below.
Geological Survey of Ethiopia (GSE)
December, 2012
3
Opportunities for Graphite development in Ethiopia
Figure 1. Location map of study areas
Geology of The Study Areas
The northeastern branch of the Mozambique Belt, a major Proterozoic structural and
metamorphic unit of East Africa extends from Kenya through Ethiopia and the horn of
Africa into southern Arabia (Warden & Horke 1984). In the Mozambique Belt of
southern Ethiopia, three major divisions (Lower, Middle and Upper Complexes) have
been differentiated by characteristic contrasts in lithology, metamorphism and structural
style (Kazmin et al. 1978). Meta sedimentary rocks (graphitic phyllites, biotite schists
and meta calcareous rocks) in the Adola area form the uppermost unit of the Upper
Complex of southern Ethiopia. On the basis of this scheme, the rocks of the Moyale
region are correlated with the lower par of the Upper Complex, and are probably Neo
proterozoic in age (Alene & Barker 1993).
According to Hussien (1999), the rock association in the Moyale area is typical of a
subduction complex consisting of metamorphosed mafic-ultramafic rocks, fore-arc and
Geological Survey of Ethiopia (GSE)
December, 2012
4
Opportunities for Graphite development in Ethiopia
accretional wedge-derived meta sediments and associated rocks. Hussien further
suggested that the lithological association in the Moyale domain indicates the existence
of oceanic crust prior to sub duction. The major orogenic belts of the Horn of Africa,
Arabian Shield and Mozambique Belt intersect in the Moyale region (Kazmin et al. 1975,
Vail et al. 1986). The local geology comprises poly deformed and metamorphosed mafic
and ultramafic rocks, granodiorites and subordinate amounts of meta sedimentary rocks.
The dominant rock units of the Moyale area are amphibole schist, quartz-feldspar-mica
schist, granodiorite, quartzite and graphite schist.
GRAPHITE OCCURRENCE AROUND KIBRE MENGIST
A long belt of graphite schist and graphitic quartzite which strikes north-south for about
60 km from Genale river down to Kenticha was identified. This belt is continuously
exposed North of Kibre Mengist. Detail laboratory analysis was not conducted due to the
limited laboratory facility and experience for the evaluation of graphite. Twenty one
graphite samples were collected and analyzed in 1990 from Kucho river, Melka Gonji
,Kibre Mengist and Kenticha area.
In 1993 a follow up exploration work was carried out in the area north of Kibre Mengist
where the highest carbon content (upto20%) was recorded during the 1990 field season.
The exploration work covered an area of 10.8km2 and two trenches were dug in Hidi Eda
area where the graphite seems superior in quality. The area north of Kibre Mengist
known as Kobe Sorsa is mainly composed of graphitic quartzite, graphite schist, biotite
muscovite schists, ultramafic rocks, granite intrusions and marble lenses. This rock units
are generally striking N20 (degree) E dipping in average 60° due west. The marble beds
are white to dark grey sometimes crystalline, massive to bedded and silty. The darker the
color is mostly associated with the graphite mineral.
The north eastern extreme of the mapped area has high quality graphite bed which is
found sandwitched between the marble lenses.This graphite bed has a thickness of about
20m.The graphitic quartzite which is compact and rarely silisified is highly enriched with
pyrite minerals. This graphite bearing rocks are mainly composed of quartz, feldspar and
Geological Survey of Ethiopia (GSE)
December, 2012
5
Opportunities for Graphite development in Ethiopia
rare mica minerals. The graphite mineral of this area is microcrystalline (amorphous)
where the graphite grains can not be seen even with a hand lense in most cases.
Hidi Eda Graphite
This area is located about 7 km north of Kibre Mengist. The area is mainly composed of
graphite quartz mica schist, biotite muscovite schist, metasandstone and granite
intrusions. Based on the physical properties of the graphite and field evidence this area
was given priority for semi- detail work. Two trenches were dug (54m) and a total of 23
channel graphite samples were collected from the trenches for analysis. The graphite of
Hidi Eda area is dark grey to black, greasy feeling and slightly weathered and
ferruginized. The graphite is fine grained (microcrystalline), it is dipping in average 45°
NW. The exposed thickness of the graphite schist is 30m having a strike length of about
450m. The area east of the exposure is a farm land which can easily be exposed by
opening pits and trenches to assure the presence of graphite. A result of analysis shows a
carbon content varying from 7.9% to 16.2% and an average from 23 samples is
11.1%carbon, 87.1% ash and 2.2% moisture content.
The average chemical composition of the ore shows 59.6% SiO2, 21.1% Al203, 3.66%
Fe203, 0.27% CaO, 1.36% ( K2O + Na2O ) and 10.9% L.O.l. The higher the alumina
content is mainly due to the high content of feldspar mineral in the rock. The average dry
density from 23 samples is 2.35g/cc.
Kucho Graphite
This area is located 5 km east of Kibre Mengist on the road to Negele, before crossing
Kucho river. A graphite body which is dark grey to black is found exposed on either side
of the road, and the local people use it to paint their houses. The graphite is exposed for
about 50m and it dips 20° due west. The graphite is soft, greasy, and loss. Five point
samples were collected and analyzed. The average chemical composition from five
samples showed SiO2 41.7%, Al203 23.2%, Fez03 14.5%, K2O 1.6%, S04 less than
o.1%, TiO2 1.1%, CaO less than 0.1%, Na2O 0.1% and L.O.I 17.8%.
Geological Survey of Ethiopia (GSE)
December, 2012
6
Opportunities for Graphite development in Ethiopia
Melka Gonji Graphite
Melka Gonji is located 20 km north of Kibre Mengist at the confluence of Genale and
Ababa rivers. The road up to Oda Buta village is accessible only by a four wheel drive. A
foot path branching to the east at the Oda Buta elementary school leads to the deposit,
and the areal distance from the road to Melka Gonji graphite deposit is about 4 km. This
graphitic rock is part of the long graphite belt which extends up to Kenticha area. Three
profiles across the strike were surveyed, and 13 samples were collected for analysis. The
main rock type of the area is quartz graphitic schist, biotite schists, amphibole schists,
graphitic quartzites, feldspatic quartzites and granites of various composition. The
graphite schists and graphitic quartzites are very compacted and mostly shows voids due
to the leaching of sulphide mineral. Greasy and black graphite veins and vein lets are
visible at the contact of the intrusive bodies. The chemical analysis shows high values of
silica, alumina, potash, and sodium. The graphite at Melka Gonji is exposed for more
than 2 km along the strike and the width of the graphite schist is measured to be about
150 m. The dip angle is 40°-60° due west.
Kenticha Graphite
Two graphite samples were collected 7 km west of Kenticha. The graphite in this area is
intruded by pegmatite veins. The average from the two samples gave a fixed carbon
content of 8.7%.Megascopic and thin section examination showed quartz, feldspar,
hematite, magnetite and pyrite minerals. The chemical analysis from the two samples
shows 59.7% SiO2, 9.4% Al2O3, 2.2% Fe2O3, 4.4%K2O, 1% S04, and L. O .I 17%.
Kibre Mengist Graphite
The area is located 5 km north of Kibre Mengist on the road to Chembi. The graphite
schist is frequently intruded by diorite intrusions and samples near the contact have high
content of carbon. Three samples were collected and the results show the highest carbon
content from all the samples collected during the fieldwork. The highest fixed carbon
content recorded is 20.0% from this area. This result according to the author does not
represent the quality of the area and the result is exaggerated due to the reconcentration
of carbon at the contact of the graphite schist and the granite intrusion.
Geological Survey of Ethiopia (GSE)
December, 2012
7
Opportunities for Graphite development in Ethiopia
Based on the preliminary results of analysis showed the author concluded that the
graphite belt from Genale river down to Kenticha can possibly be a potential resource
area for graphite. A systematic exploration work on this graphite belt may lead to a good
quality economic graphite deposits. Detail exploration work by pitting and trenching on
the area north of Kibre Mengist is advisable. More tests have to be carried out on the
graphite body at Hidi Eda to ensure the quality and quantity of the graphite. Additional
trenches and pits are also necessary to delineate the graphite body.
Moyale Graphite
Moyale is located 775km south of Addis Ababa at the northern Kenya border.
The graphite occurrence is about 6 km west of Moyale town at Gedemssa locality
(figure1). Investigations of the Moyale graphite have comprised mapping the graphite
body by geological and geophysical methods, analysis of the graphite carbon content, and
determination of the size and texture of the graphite grains. Preliminary efforts have also
been made to concentrate the graphite by flotation techniques.
Based on the integrated survey carried out the authors concluded that the economic
potential of graphite bearing rock depends mainly on the carbon content and flake size,
since the market price for graphite reflects these two characteristics. The average grade of
the Moyale graphite schist ranges between 7 and 11% (mean9.1%).The Moyale graphite
schists therefore have moderately low graphite contents. However, the graphite grains
have their longest axes greater than 100micrometer, which suggests that flake size is
optimal and that it is technically feasible to produce graphite concentrates using the
available technology.The mineral resource of the area is estimated to about 450000 tones
of graphite.
ABOUT THE MINISTRY OF MINES
In compliance with the market oriented economic policy of Ethiopia, the parliament
declared that it is the continuing policy of the Federal Government in the national interest
to foster and encourage private enterprises in developing economically sound and stable
mineral mining.
Geological Survey of Ethiopia (GSE)
December, 2012
8
Opportunities for Graphite development in Ethiopia
Accordingly, the Federal Government’s Ministry of Mines and Energy is responsible to
administer and supervise all large scale mining operations including issuing prospecting,
exploration and mining licenses for foreign investors and to these in joint venture with
Ethiopians as per the reform issued in 1998 on the Mining proclamation following the
realization of previous short comings of earlier laws and policies.The reform clearly
stipulated the responsibility of National Regional Governments to issue licenses and
administer all small scale mining operations owned by Ethiopians and collecting all fees
in addition to issue prospecting and exploration licenses for national investors.
Mining Legislation
In June 1993 new Mining and Mining Income Tax Proclamations were issued having
considered knowledge-based experiences in some competitive countries and given the
following provisions;
• Invite private investment in all kinds of mineral operations;
• Provides a prospecting license for one year;
• Provides an exploration license for an initial period of three years and renewed twice for
one year each;
• Provides a mining license for 20 years and renewed for 10 years unlimitedly;
• Guarantee the licensee’s right to sell all the minerals locally or abroad giving marketing
freedom;
• Provides for exemptions from custom duties and taxes on equipment, machinery,
vehicles and spare parts;
• Gives securities of tenure;
• Gives clear provisions on fiscal and other issues;
• Considering taxation on repatriation of profits and capitals, a licensee shall pay a 2-5%
royalty on ad Val Orem at production site, and a 35% income tax on taxable income.
Taxable income is computed by subtracting from gross income for any accounting
year all allowable revenue expenditure, a four years straight line depreciation,
reinvestment deduction and permitted loses; and
• The mining proclamation guarantees the opening and operation of a foreign currency
account in banks in Ethiopia, retention of portion of foreign currency earning and
Geological Survey of Ethiopia (GSE)
December, 2012
9
Opportunities for Graphite development in Ethiopia
remittances of profits, dividends, principal and interest on a foreign loan etc. out of
Ethiopia.
Of course this fiscal package is still subject to frequent reviews for maintaining a balance
between the objective of the government and investors as is evident by a series of
amendments of the 1993.
Investment Climate of Ethiopia
The Federal Democratic Republic of Ethiopia has created a conducive investment
environment to ensure and promote private investment to play a leading role in the
development of the national economy. This favorable climate for foreign investment has
been created as consequence of the solid foundation of political and economic reform,
particularly the stably secured macroeconomic reforms which are achieved by carefully
managed sequential reforms coupled with faire fiscal and monetary policies. By the
virtues of Ethiopia’s unique and untapped natural resources, its proximity to middle east
and European markets, its 80 million population, and huge labor force both disciplined
and easily trainable are some of the comparative advantages worthy of consideration
while investing in Ethiopia. This is further enhanced by specific incentives and efficient
administrative procedures.
Mineral Investment
Between 1974 and 1991 private investments were not allowed in the mineral sector. The
government was fully responsible for the exploration and development tof the sector,
before the advent of the new economic policy of Ethiopia. In compliance with the new
market economic policy of Ethiopia the parliament declares that it is continuing to update
the policy of the Federal Government in the national interest to foster and encourage
private enterprises in developing economically sound and stable mineral mining.
For a successful implementation of the policy, a number of steps have been taken aiming
to boost the confidence of the private sector following the government’s strong believe
that rapid mineral development can only be realized when the private sector is given full
right of operating managing and owning mineral enterprises.
Geological Survey of Ethiopia (GSE)
December, 2012
10
Opportunities for Graphite development in Ethiopia
This is the underlined reason for the government’s active response to the concern of the
International mining Companies. Accordingly it has restricted its role to basic mineral
resources exploration, regulation and promotion only; To avoid the fear of controlling a
large tract of prospective land by state owned companies, and to avoid the fear of seeable
high risk due to unexpected unfair competition with state owned enterprises.
In this connection a measure stick for such track record of the government’s commitment
is manifested by the privatized Lege Dembi Gold Mine, the only one government owned
large scale gold mining, and the Kenticha Tantalum Mine which is already in the pipeline
for privatization. This includes the reform of the mining law which is taking place since
1993 and many changes that have happened to justify the sincerity ofthe government.
Furthermore the commitment is much affirmed following the establishment of a fair and
clear cut mining legislation giving investors assurances of the fruits of their success. It
constitutes a fair setup of efficient and effective licensing and mineral right
administration system, a fair set of environmental laws, rules to monitor and mitigate and
reclamation effects by mining operation, fair laws to regulate the safety and health of the
work fore and securing of tenure. It also gives freedom to license holders with a number
of incentives including low royalty, exemption from custom duties and taxes on the
equipment, machineries vehicles, and spare parts necessary for mineral operation with a
10 years provision to allow investors to carry forward losses.
Geological Survey of Ethiopia (GSE)
December, 2012
11
Opportunities for Graphite development in Ethiopia
REFRENCES
Amruta Deshpande, Graphite properties (Website, published 4/27/2010)
Donald D.Carr senor editor; Industrial Minerals and Rocks
Million H.Micael(1995), Kyanite,Talc and Graphite exeploration north of Kibre Mengist
Haile Michael Fantaw etal. (1999), The Moyale graphite deposit, southern Ethiopia
Hussien, B. 1999.The geology, structure and geochemistry of the crystalline rocks of the
Moyale area, southern Ethiopia; Implication for tectonogenesis of the Precambrian
basement,Ph.D thesis, universityof Tubingen, Band 50,102pp.
Nesibu S.and several co-authors,1998;Integrated geophysical survey of Moyale
graphite;unpublished report Ethiopian Institute of Geological Survey.
Kazmin V. etal.1978;The Ethiopian Basement;Stratigraphy and possible manner of
Evalution,Geologische Rundschau67,531-546.
Warden, AJ. etal. 1984 The Geological Evolution of NE-Branch of the Mozambique Belt
(Kenya, Somalia and Ethiopia), Mitteilungen der Oesterreichischen Geologischen
Gesellschaft77,161-184.
Geological Survey of Ethiopia (GSE)
December, 2012
12
Opportunities for Graphite development in Ethiopia
Prepared by
Degife Shiferaw
Geoscience data Directoriate,
Geological Survey of Ethiopia (GSE)
P.O.Box 2302, AddisAbaba,Ethiopia
Tel: (251-1) 46 33 25
Fax: (251-1) 46 33 26, 71 20 33
Website: www.geology.gov.et
E-mail:
[email protected]
Geological Survey of Ethiopia (GSE)
December, 2012
13