On the south-eastern extremity of Spilsby Island, there are concentrations of molybdenite and scheelite that occur either in an open vein system or as disseminations, and also in pods, usually associated with quartz. The most important host rock is an even grained pink granite which is enclosed by less strongly mineralised porphyritic grey granite. To date, 16 diamond drillholes have been drilled on land by Kennecott Explorations (Aust.) Pty Ltd and by the SA Department of Mines, for a total penetration of 2581 ft 6 in., to indicate limits and grade of the deposit. Several holes disclosed significant concentrations of molybdenite and scheelite with minor copper and bismuth, but overall the sporadically mineralised zone is of too low a grade to support any mining operation. Reserves of less than 250,000 tons of rock containing ~0.25% combined MoS2/WO3 have been outlined by all drilling. SADM's recent work entailed the deepening of vertical DDH 12 from 50 feet to 330 feet total depth, plus the diamond drilling of four new inclined holes from surface, each to 200 feet 3 inches total depth, all having a low angle eastwards to north-eastwards declination. These holes attempted to trace subsurface mineralisation inland from cored intercepts that had earlier been made in holes DDH 1, 4, 10 and 11. The direction of drilling was chosen so that the holes would cross-cut the shallow north-west plunging synclinal structural configuration of the mapped outcropping granite host rocks. Non-economic mineralisation was encountered in holes 13, 14 and 15, while nos 12 and 16 proved to be barren.