Production from the Cattle Grid orebody commenced in August, 1974._x000D_
This followed a recent discovery arising from an extensive exploration programme involving stratigraphic drilling, geochemistry and geophysics._x000D_
Located some 4 km west of the original copper occurrences at Pernatty Lagoon the discovery was found to contain 4.6 million tonnes of ore averaging 2.4% copper. The ore is a "sandstone copper" type localised near the disconformity between two Precambrian (Adelaidean) stratigraphic units, the Pandurra Formation and the Whyalla Sandstone._x000D_
The mineralisation roughly follows the interface between these units and occurs in fractures, vugs and along bedding planes. The mineralogical character of the ore is somewhat complex consisting of chalcocite and bornite, with associated chalcopyrite, sphalerite, pyrite and other less common sulphides. 1. Senior Geologist, Pacminex Pty._x000D_
Limited, Sydney, N.S.W. 2. Mine Geologist, for Mt. Gunson Mines, Pacminex Pty. Limited, Mt. Gunson, S.A.