A petrological examination of selected diamond drill core samples compared lithology and geochemistry between various sections of the Mount Gunson copper deposit host sequence and between different areas. There appears to be little chance of discovery of a large stratiform sulphide deposit associated with bituminous black shale deposition in a deep offshore palaeoenvironment. Rather, the evidence suggests that the Tapley Hill Formation accumulated in a shallow water environment. Tapley Hill Formation sulphide deposits discovered so far in the CSR tenements on the Stuart Shelf are small, scattered concentrations in restricted basin environments around the fringes of the Pernatty Culmination, where there is potential for small discoveries. Sulphides associated with the Tapley Hill Formation shales and dolomites are possibly too fine for economic recovery by present day metallurgical technology.