Geological mapping and the interpretation of drillhole data from the vicinity of the recently defined Southern orebody extension at Beltana (including 4 new diamond holes totalling 1600 feet) has enabled the licensee to formulate likely parameters of the formation of the zinc-lead mineralisation within dolomitized Cambrian Ajax Limestone. Investigations have shown the probable primary source of the massive mesogenic willemite/hedyphane ore to be zinc sulphide associated with major regional thrust faults which form the orebody hanging walls. It was found that at Beltana the mineralisation in the Southern Extension carries to a greater depth than that of the Main Orebody or the Northern Extension. Furthermore, a marked decrease in zinc grades and an increase in lead grades with depth was noted in the former situation. From drilling section calculations the estimated tonnage and grade of the Southern Extension orebody is 187,850 tons at 19.3% Zn and 6.7% Pb. Ongoing geological mapping has addressed thrust fault zones and a series of anticlines and synclines developed within Willouran and Cambrian sedimentary rocks lying to the west and east respectively of the Beltana orebodies. Detailed geological mapping at 1:4800 scale has now been completed over all of the licence area. A short programme of percussion drilling was conducted to test a microgravity anomaly identified to the south of the Southern Extension orebody, but no mineralisation was encountered. The Beltana type ore, due to its complex and most unusual gross chemical composition, appears to be overly difficult to treat. Metallurgical research into the most economically suitable and environmentally benign method for treating Beltana willemite ore has lately been undertaken by E-Z at Risdon in Tasmania, and also by the Broken Hill Associated Smelters at Port Pirie in South Australia. The relative viability of using a modified slag fuming process versus direct leaching of ore (and subsequent conversion of basic ZnSO4 concentrates to zinc metal) was assessed, and the feasibility of safe nearby disposal of process by-products was also considered, particularly as to how to best handle arsenic precipitates in kiln dust and a suite of heavy metals present in silica residues of leaching. No presently tractable methods for either ore treatment or by-product disposal were identified, due to a number of apparently insurmountable technical problems.