Exploration Licence 1258 "Mingary" was granted to Mount Isa Mines Ltd in November 1984. The area, of 1185 square km lying 40 km north-east of Olary, had been the subject of exploration of the Palaeoproterozoic metasedimentary basement for Broken Hill style base metal mineralisation for many years prior to the grant. MIM made a review of this past work, then undertook a regional programme of ironstone lag sampling. RAB drilling was initiated at the Cockburn prospect (426 holes, aggregate 4909 m), followed by percussion drilling (14 holes, 2247 m). This work disclosed buried gahnite-bearing gneisses, and gave a best intersection of 8 m at 0.5% Zn. Acquisition of an aerial magnetic/EM survey and of numerous ground IP and SIROTEM surveys identified a number of targets considered worthy of follow-up. Over the next two years, an extensive programme of RAB drilling along variably spaced traverses was undertaken, while additional IP and SIROTEM surveying refined existing targets and generated further targets which were tested by percussion and diamond drilling. In total, this drilling phase comprised 350 RAB holes (9774 m), 14 percussion holes (2008 m) and one percussion/diamond hole to 224.5 m. During this time structural, petrological and lead isotope studies of some drillhole samples of the Mingary basement gave encouraging evidence of its stratigraphic and age affinities to the Broken Hill orebody host rock sequence. The focus of exploration then shifted onto the Bimba Formation, a potentially metalliferous calcsilicate horizon overlying the distinctively magnetite-bearing Upper Albite horizon, with the new exploration emphasis being placed on investigating magnetically anomalous areas. Over the next four years, the conduct of ground magnetic, IP and TEM surveys produced numerous targets on which drilling investigations comprised 1322 RAB holes (65,430 m), three rotary/diamond holes (649.4 m total), 68 aircore holes (5080 m), and 4 rotary mud holes (121 m). While a number of bedrock Pb-Zn anomalies were reported from the RAB drilling (up to 1770 ppm Zn and 1510 ppm Cu), the best result obtained from follow-up aircore and diamond drilling was only 2 m @ 0.41% Zn, in diamond hole DM4 at Cottage Bore prospect. Attempts to detect this concealed Bimba Formation sphalerite mineralisation with surface geophysics and geochemistry were made via trials of magnetometric resisitivity (RRMIP) and soil gas survey methods, under the auspices of the SA Department of Mines, but produced no significant anomalous results. Late in 1993, a joint venture was negotiated between MIM and CRA Exploration, with CRAE to act as managers, essentially to explore for commercial zinc deposits. Initial regional geochemical sampling included the media of gravel (targeting diamonds), BLEG stream sediment, and soil, ironstone lag and rock chip. Follow-up soil sampling at Lawsons prospect identified elevated zinc over several square km. Geophysical survey methods used during this time included IP, ground magnetic and gravity, and several potential drilling targets were identified. Reverse circulation and diamond drilling at Lawsons prospect (24 RC holes for 2193 m, 4 diamond holes for total 212.2 m) returned a best intersection of 28 m @ 0.41% Zn. Drilling at other prospects comprised 12 RC holes for 1357 m.