Under cover

An Australian geophysical data acquisition system, dubbed Geoferret, has the potential to significantly enhance the mining industry's approach to discovery and deep extension of sulphide ore bodies.

Developed by WMC Resources (WMC) in conjunction with the Western Australian-based geophysical instrumentation and software specialist Electromagnetic Imaging Technology (EMIT), Geoferret uses electro-magnetic techniques to help explorers see electrically-conductive minerals deep underground with great clarity.

The Geoferret system itself sports a series of distributed EM sensor coils and associated receiver electronics that provide simultaneous data acquisition capability. It also has a Global Positioning System integrally attached to each sensor that delivers synchronised time and positioning measurements. A hand-held computer or Personal Digital Assistant can collect data from the sensors via a wireless network, displaying data and quality control information, and storing the data until an operator wishes to transfer it to a laptop computer for modelling.

'Conventional EM tools can detect conductive ore bodies, but due to geological, instrument and atmospheric noise the depth of accurate investigation is commonly limited to less than 200 metres in the presence of conductive cover. Geoferret can and has detected or confirmed conductive minerals at more than 500 metres below very conductive cover with far greater clarity than conventional tools,' said WMC's General Manager Exploration, Bart Suchomel.

WMC has been working on development of Geoferret since late 2000 and began field trials at the Cliffs nickel sulphide prospect (south of WMC's Mt Keith Nickel Operations in Western Australia) in mid-2003. Geoferret has assisted in the discovery of the North Cliffs extension and the Olympia nickel sulphide prospect at Collurabbie, also in Western Australia.