The Balhannah Mine situated on Section 4048, Hundred of Onkaparinga produced 9 tons of bismuth and 170 tons of copper during the period 1869-1875. Subsequent exploration during 1881, 1889, 1936 and 1949 did not locate additional ore. The present investigation was undertaken, at the request of the operator when driving had disclosed primary bismuth-copper minerals within a series of minor quartz-carbonate veins on the 79 foot level. Surface and subsurface geological mapping showed that in the original orebody chalcopyrite, bismuthinite and minor gold occurred within a northwesterly striking, steeply-dipping quartz-carbonate vein up to 10 feet wide and cross-cutting carbonaceous schists, schists and meta-siltstones of the Balhannah Shale Member (Upper Proterozoic). The vein has been segmented by later north striking, east dipping faults. It is considered unlikely that economic, extensions of the original ore shoot are present.