SERVICES

REMOTE SENSING IN MINERAL EXPLORATION

The use of remote sensing in mineral exploration began some 60 years ago with hand-held cameras being pointed out of aircraft windows and has since evolved through stereoscopic aerial photography to sophisticated space age technology, with satellite and airborne multispectral and hyperspectral digital imaging systems.

When the Landsat multispectral scanner (MSS) began operations in the early 1970's, remote sensing geology took an enormous leap forward but still functioned largely by way of photogeological interpretation of hard copy. Since then, the Landsat Thematic Mapper (TM) instruments have provided the geological user with information relating to specific groups of minerals, specifically the iron oxides and clays. However, the data remains coarse and of general purpose only with low spectral and spatial resolution, requiring sophisticated statistical processing techniques not readily understood by the average geological user.

In the 1980's, airborne remote sensing began with the development of the Airborne Thematic Mapper by Daedalus, the Geoscan instruments (MKI and MKII) by Australian Carr Boyd Minerals Ltd., the Collins' imaging spectrometers developed by Geophysical and Environmental Research Corporation of Millbrook, New York and the Airborne Visible InfraRed Imaging Spectrometer (AVIRIS) developed by the Jet Propulsion Laboratory, Pasadena.

All of these instruments offered increased spectral and spatial resolution over their satellite borne predecessors and, the three latter in particular, provided geological users with a means of discriminating and mapping individual mineral species and alteration assemblages.However, it has only been recently, in the 1990's, that the means of processing this data has become available to the average geological user through the development of low cost, commercial image processing and analysis software for desktop PCs. The rapid growth in computing power and storage capacity in PCs has allowed the very large data files captured by the airborne instruments to be handled in a time frame compatible with the needs of mineral exploration. Furthermore, the data can nowadays be georeferenced, the inherent distortion in the data caused by the operation of such instruments on a relatively unstable airborne platform can be ironed out and the data integrated with other exploration datasets.

We are now witnessing the dawn of a technological age in mineral exploration where diverse datasets can be integrated and interrogated for specific parameters and prospectivity maps generated. The careers of AGARSS' geologists have taken shape in this dynamic environment and they have all been very quick to assimilate the new technologies as and when they have appeared on the scene.

In Saudi Arabia, Bob used Landsat TM data in regional mapping and exploration before being involved in the assessment of airborne thematic mapper data to mineral exploration in the Wadi Shajiah district. Ten years ago, he became responsible for the development of mineral exploration programmes on behalf of Carr Boyd Minerals Ltd using data collected by their Geoscan MKI & MKII airborne multispectral scanners.

As General Manager of Geoscan Pty. Ltd., Bob extended the acquisition of airborne spectral data into places such as Bolivia, Chile and Brazil and developed exploration applications for precious and base metals, industrial minerals such as kaolinite, talc and gypsum, as well as oil, gas and water resources. Under Bob's management, Geoscan not only acquired spectral data for clients on a commercial basis but also processed, interpreted and became directly involved in their clients' exploration projects.

This concept has been carried forward into AGARSS where Bob is supported by Neil Fraser, a geologist with over 10 years experience in exploration and remote sensing prior to obtaining a Graduate Diploma in GIS. Before obtaining his graduate diploma, Neil worked as a remote sensing geologist with Geoscan Pty. Ltd. for a year before joining AGARSS in July 1995.

Examples of work AGARSS has been involved in

Landsat TM processing and interpretation over central and northern Peru in support of Zinc and Gold exploration programmes,

Savage Exploration, Peru Ltd. Geoscan MKII processing and interpretation over Davyhurst district, Western Australia in support of Gold exploration,

Consolidated Gold N.L. Landsat TM interpretation over the Ashburton Basin, Western Australia, in support of Gold and Base Metal exploration,

Bacome Pty. Ltd. Geoscan MKII processing and interpretation over Uaroo district, Western Australia in support of Gold and Base Metal exploration,

A. Strong. Landsat TM and Eosat Radar processing and interpretation over Northern Vietnam in support of Zinc exploration,

Leader Resources Ltd. Landsat TM and GER DAIS 63 processing and interpretation over Huancavelica and Cordillera Negra, Peru, in support of Gold and Base Metal exploration,

Cia. De Minas Buenaventura S.A. GER 63 Band Digital Airborne Imaging Spectrometer (DAIS 63) processing and interpretation over parts of Southern Peru, in support of Gold exploration,

Newmont Peru Ltd. GER DAIS 63 processing and interpretation over Corimayo, Peru, in support of Gold and Base Metal exploration, North Compania Minera S.A.

Landsat TM processing and interpretation over Southern Peru in support of Gold exploration, Minera Andes del Norte S.A. Geoscan MKII processing and interpretation over parts of the Ashburton Basin, Western Australia, in support of Gold exploration,

Agar, R.A. & Villanueva, R., 1997. Satellite, Airborne And Ground Spectral Data Applied To Mineral Exploration In Peru. Proc. 10th Thematic Conference on Geologic Remote Sensing, Denver, Colorado, November 17th-19th 1997.

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.

Agar, R.A. & Villanueva, R., 1997. Aplicaciones De La Data Multiespectral Del Ger Dais 63 En La Exploraci—n De Yacimientos En Huancavelica, Perœ. IX Congreso Peruano de Geolog’a, Resœmenes Extendidos, Sociedad Geol—gica del Peru, Vol. Esp. 1, Lima, pp221-224.

Agar, R.A., 1996. Multi-spectral data and their applications for Gold exploration in Latin America. Keynote Presentation, Proc. 2nd International Gold Symposium, Lima Peru.

Agar, R.A., 1994. Geoscan airborne multi-spectral scanners as exploration tools for Western Australian diamond and gold deposits. In:- Dentith, M., Groves, D., Trench, A., & Frankcombe, K. (eds). "Geophysical Signatures of Western Australian Mineral Deposits", Geology and Geophysics Dept. (Key Centre) & U.W.A. Extension, The University of Western Australia, Publication No. 26, pp435-447.

Agar, R.A., 1994. Geoscan airborne multi-spectral scanners as applied to exploration for Western Australian diamond and gold deposits. Proc. 10th Thematic Conference on Geologic Remote Sensing, San Antonio, Texas.

Agar, R.A., Fraser, N.R. & Lockett, N.R., 1994. The Geoscan airborne multispectral scanner as an exploration tool applied to the El Halcon prospect, Chile. In:- "Mining in Latin America" IMM, Santiago, Chile, Chapman & Hall, London, pp151-164.

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.

Agar, R.A., 1992. Geological applications and limitations of airborne multi-spectral scanners; their availability, cost effectiveness and future. Abstracts of Proceedings, 11th Australian Geological Convention, Ballarat, Vic. Pp308-309.

Hatch, A., Taylor, W.R., and Agar, R.A., 1992. A remote sensing study of kimberlite and lamproite pipes using Geoscan Airborne Multi-Spectral Scanner imagery; examples from the Kimberley, Western Australia. Abstracts of Proceedings, 11th Australian Geological Convention, Ballarat, Vic. Pp309-310.

Agar, R.A., 1992. Geological applications and limitations of airborne multi-spectral scanners; their availability, cost effectiveness and future. Proc. 6th Australasian Remote Sensing Conference, Wellington, New Zealand, pp259-273.

Derriman, M.D.J., & Agar, R.A., 1990. Gold and base metal exploration in the Pilbara craton, Western Australia, using the Geoscan Airborne Multi-Spectral Scanner. Proc. 5th Australasian Remote Sensing Conference, Perth, W.A.

Agar, R.A., and Legg, C., 1987. Application of the airborne thematic mapper to detailed geologic mapping in Wadi Shajiah, Saudi Arabia. Saudi Arabian Deputy Ministry for Mineral Resources Open-File Report.