An integrated geo-electrical survey on the nangaroo copper—zinc prospect, near Leonora, Western Australia

Abstract

High-grade massive copper—zinc sulphides were intersected during exploration diamond drilling of a prospect in the Nangaroo area, Western Australia. Further diamond drilling had little success and a programme of down-hole and surface exploration geophysical techniques was applied in an attempt to obtain information on the geometry and extent of the sulphides etc. This programme consisted of applied potential/IP potential surveys utilising a current electrode placed directly within the massive sulphide drill intersection, electrical logging of available drill holes and a surface gradient array I.P. survey. The applied potential/IP potential data were successful in providing potential patterns at the surface indicating the strike extension and up plunge direction of the sulphide body. The combination of applied potential/IP potential data, drill hole electrical logs and gradient array IP data provided complementary information on the mineralis ation and this permitted estimation of the dip and plunge of the body and indicated the presence of two discontinuities. The combined data indicated a shallow mineralised body with a gentle northerly plunge and a steep dip to the west. Subsequent diamond drilling confirmed the extent and attitude of the body indicated by the geo-electrical data. Later research studies confirmed the electrical properties of the mineralisation and showed that the mineralisation was a moderate EM conductor.