Widespread copper carbonate and weathered, disseminated sulphide mineralisation occurring within large diapiric breccias at Oraparinna and Wirrealpa, that are located respectively ~ 35 km north-northeast of Hawker and 20 km east of Blinman, was found to be mainly associated with propylitically altered intrusive basic to intermediate igneous rocks. In addition, syngenetic lead-zinc occurs in the Cambrian Wilkawillina Limestone, and syngenetic copper in the Proterozoic Bunyeroo Formation. No base metal deposits of economic significance were located by an exploration programme consisting of tectonic lineament and rock structural photointerpretation, magnetic interpretation and reconnaissance stream sediment sampling, followed by detailed prospect grid geological mapping, rock chip and bulldozer trench sampling, plus diamond (3 holes) and hammer drilling (10 holes) totalling 1028 and 1126 feet respectively. The majority of drill samples assayed less than 0.1% Cu, with mineralised intersections being separated by broad intervals of barren rock. Notwithstanding the disappointing results from this drilling on promising geochemical anomalies, the work undertaken has led to formulation of many new ideas, presented here, concerning factors which might have controlled the genesis, nature and distribution of known stratiform base metal mineralisation in the region. A critical feature remains the interpreted layered mafic igneous intrusion, now completely fragmented by diapiric faulting and altered by hydrothermal / deuteric activity and supergene leaching, which occupies much of the near subsurface section in the Oraparinna Diapir copper - barite prospect zone. Various recommendations are made for further exploration work aimed at finding concealed economic concentrations of mineralisation inside or adjacent to this zone.