Gunsight prospect was discovered in the late 1960s during the follow-up of anomalous copper detected by a stream sediment survey. In 1972-73 Dampier Mining Pty Ltd drilled eleven percussion holes (totalling 537 m) and eleven diamond holes (1764 m) over the 1000 m strike length of the potentially mineralized zone. Assay work by Marathon Petroleum Australia Ltd in 1980 indicated that cobalt and rare earth elements were associated with the copper uranium mineralization. Drilling by Marathon in 1981 intersected further sub-economic grades of Cu-Co-U-REE mineralization. Geological investigations have led to the interpretation that the sequence represents a volcano-sedimentary pile in which sulphides have been deposited in a stratiform/stratabound sense. Dominant sulphide phases present include chalcopyrite, chalcocite, digenite, covellite, cobaltian pyrite, cobaltian arsenopyrite and uraninite. Cerium and lanthanum are also present. Remobilization during tectonism is interpreted to have occurred on a local scale. Three major deformational events are interpreted to have deformed the mineralization into a series of small pods.