Download The RIGHT way to evaluate historical drill data

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CENTRAL AFRICA | DRC – SERVICE PROVIDERS
The RIGHT way to evaluate
historical drill data
When considering using
drilling historical data in a
Mineral Resource estimate,
there are two extremes – do
not use at all or use without
reservation. In most cases
the answer lies somewhere
in between, writes JEREMY
WITLEY, The MSA Group’s
Principal Resource Consultant.
T
he MSA Group is involved in
several projects where the drilling
database contains historical data,
i.e. collected prior to the adoption
of stringent reporting criteria such as those
contained in JORC (2012) and NI 43-101.
For older projects, particularly mines that
project developers are bringing back into
production from care and maintenance,
quality of the logging, sampling
and assaying; location of the data
in space (down-hole surveys and
collar surveys); data storage; and
integrity of the data.
In almost all cases some form
of verification is required for
example twin drilling, re-logging
and re-sampling of a selection
of holes or the residues, should
Total oxidation of historic nickelthe condition of the remaining
sulphide core – an example where the
sample’s condition is likely not good
sample be reasonable. A decision
enough to yield meaningful result
lts
by a qualified/competent person
could be to express risk in terms
of classification (inferred, indicated and
the historical drillhole data tends to be
measured), perhaps to use only certain
voluminous and it is desirable to take
aspects of the data or only use the data to
cognisance of these data in a Mineral
inform the geological model and not the
Resource estimate.
grade estimate.
For mining companies looking to
Because there is no single solution that
compile a Mineral Resource estimate
can be applied to all projects, historical data
under such circumstances, a multitude of
should always be considered on its own
factors should be considered: such as what
merit for individual scenarios. MRA
is known about the data collection; the
The MSA Group is a leading provider of
exploration, geology, mining and environmental
solutions to the mining industry.
Tel:
+27 (0)11 880 4209
Email:
[email protected]
www.msagroupservices.com
/company/the-msa-group
themsagroup
@TheMSAGroup
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