Exploration for gold and base metals undertaken over an ~9500 square km prospective area of no basement outcrop centred near Coober Pedy, searching for possible Broken Hill, Tennant Creek or Olympic Dam type mineralisation, initially comprised the acquisition of three detailed airborne magnetic/radiometric surveys starting in May-June 1992, all flown by Geoterrex along north-south or east-west lines spaced either 400 m or 800 m apart respectively, followed by the conduct of defining ground magnetic and EM surveys and 2D geophysical modelling of ten selected anomalies, and then test RC drilling (by 17 vertical or inclined holes, total 4335 m). Elevated gold, base metal and REE concentrations were encountered in drill cuttings samples from seven of the drillholes, including a best intercept in hole NC9202, from below 168 m hole depth, of 28 m @ 1428 ppm Cu, 614 ppm Pb, 2330 ppm Zn, 2 ppm Ag, and up to 1% Ce and La, hosted by rocks having petrologically inferred skarn or carbonatite affinities. This particular hole had been drilled to test the M5 magnetic anomaly, subsequently renamed the Cadi prospect. Two large regional gravity surveys were acquired by Geoterrex for BHP during 1993, both covering 1 km x 500 m grids. The first survey was read during the period 20/3 to 13/5 over an area centred ~50 km north-east of Coober Pedy, and comprised 2723 stations plus 559 infill stations. The second survey was read during the period 22/7 to 27/8 over an area centred ~70 km west of Coober Pedy, and comprised 2503 stations plus 341 infill stations. The aim of these surveys were to prioritise the numerous magnetic anomalies identified from the earlier aeromagnetic surveys, and also to identify gravity anomalies that have no associated magnetic features.