Regional geological mapping over an area of interpreted major structural weakness within the ?Lower Proterozoic crystalline basement of the Musgrave Block identified two associated styles of mineralisation. Minor Cu mineralisation is localised in a gabbroic dyke and along a large east-west trending shear zone. Of more particular interest is a large basic/ultrabasic dyke intruded along a fracture in the complexly faulted basement. The dyke, 9 miles long and up to 500 feet wide, is of a different orientation to all other dykes in the area. Surface indicator rocks suggest that the central portion of the dyke is of ultrabasic composition. A programme of soil sampling over a 10,000 foot strike length has revealed high Ni values (up to 1200 ppm) in soil, while rock samples from a limonitic gossanous zone gave assays up to 5200 ppm Cu, 5400 ppm Ni and 1200 ppm Co.