| What is GIS in Mineral Exploration? During the last
few years, there has been an extremely rapid advance in processing power and storage
capacity in personal computers. This has corresponded to a dramatic advance in the
capability of software packages available to run on these powerful, relatively cheap
computers. One area that has advanced dramatically has been the ability to handle spatial
data.
Emerging from earlier CAD packages has been Geographical Information Systems (GIS)
which allow the display, manipulation and analysis of linked textual and spatial data.
The use of GIS in mineral exploration is now widespread, allowing the integration of
disparate digital datasets into a single, unified database. This database is designed such
that each specific data entity, such as geology or airborne magnetics, is stored in its
own compartment, or layer. This allows the comparison of any number of these entities at
one time in ships between the various data types. An approach such as this gives a
geoscientist the tool required to analyse the interaction between the data layers which is
necessary in understanding geological processes.
AGARSS has been quick to embrace the concept and use of GIS in mineral exploration.
GIS is an ideal partner to image processing systems allowing the rapid manipulation,
comparison and interpretation of the various image processing interpreted products with
other relevant datasets. In this way, for example, a lithological discriminator
algorithm applied to remotely sensed data can have geology overlaid, allowing the
geological map to be updated using the remote sensing data as a background. The
georeferenced remote sensing data can be used to produce a number of interpreted
products which can be supplied to the client in a format compatible with the client's
existing digital datasets, allowing all relevant data to be integrated into the one GIS
database. An approach such as this ensures that useful data is always readily available
for interrogation at a moments notice, at any scale required in conjunction with any other
dataset, rather than lying unused in a map cabinet.
It is imperative that the maximum amount of information be extracted from each data
source in order to enhance the chances of exploration success. The use of GIS greatly
increases those chances.
In addition to the electronic light table approach outlined above, AGARSS recommends to
its clients to go one step further, particularly for regional studies. The recommended
approach is to compile all of the available geoscientific data within the GIS in the
context of an exploration model in order to produce a mineral potential map. Careful
consideration must be given in developing the model such that all of the relevant,
important aspects of the deposit being sought are represented. The model is also very
important in deciding what weightings to apply to each of these aspects. In the final
analysis, these weightings may be arbitrarily applied by a geologist, with an intimate
knowledge of the model and the deposit style sought, who decides which aspects related to
the deposit are most important, ranging down to those of least importance. Another
approach, which is not applicable in all situations, is to use a statistical method in
order to decide upon weightings. The final result will be a combination of all of the
weighted values, producing a map which ranks the study area by degrees of perceived
prospectivity.
Examples of work AGARSS has been involved in
Gold:- Integration and interpretation of aeromagnetic, radiometric, geological and
geochemical data over Mt. Magnet South, Western Australia, into a GIS database on behalf
of Signature Resources Ltd.
Gold:- Integration and interpretation of Geoscan MKII, aeromagnetic and geological data
from the Davyhurst region, Western Australia, into a GIS database on behalf of
Consolidated Gold N.L.
Gold, Base metals:- Integration, interpretation and modelling of Geoscan MKII,
aeromagnetic, geochemical and geological data from the Uaroo project, Western Australia,
into a GIS database on behalf of A. Strong.
Initiated the digitisation and integration of nationwide geology, geochemistry and
geophysical data into a national geoscience information system, Republic of Zambia, 1981.
Platinum Group Metals, Nickel, Chromium, Gold:- Integration of ground survey,
geological, aeromagnetic, geochemical, DEM, spectral and drilling data into a GIS data
package on behalf of Weld Range Joint Venture (Sons of Gwalia, 65%, Dragon Mining, 35%),
Cue, Western Australia.
Fraser, N.R., & Agar, R.A. 1997. GIS Integration Of Airborne Multispectral,
Geophysical And Other Mineral Exploration Data At The El Halcon Porphyry Copper Prospect,
Copiap—, Chile. Proc. 10th Thematic Conference on Geologic Remote Sensing, Denver,
Colorado, November 17th-19th 1997.
Fraser, N.R., 1996. A Mineral Exploration Strategy Using An Index Overlay Model With
Multiple Class Input Maps. Unpublished Thesis.
Fraser, N.R., 1996. A Mineral Exploration Strategy Using An Index Overlay Model With
Multiple Class Input Maps. Unpublished Thesis, Curtin University of Technology.
De Largie, D.A., Lockett, N.H., Agar, R.A., and Lyon, R.J.P., 1993. An integrated
Landsat MSS, aeromagnetic, air photographic and Geoscan AMSS approach to gold exploration
in Nevada. Proc. 9th Thematic Conference on Geologic Remote Sensing, Pasadena, Ca. U.S.A.,
V.II, pp1097-1110.
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