A memo received from Asarco's Arizona-based geologist Mr J H Courtright (27 December 1978) drew the attention of that company's Perth office staff to the similarities between the Anabama breccia pipes, which he had seen during a visit to the prospect made in early 1970, and other breccia pipes occurring on top of molybdenum deposits in North and South America. Following a discussion between the present author and Mr Courtright which took place in Asarco's Tucson office in September 1979, and because of recent intensive acquisition of ground by competitor companies in South Australia, an application for an exploration licence covering the Anabama prospect was lodged with the South Australian Mines Department in January 1980. The project area was mapped during June 1980, and the stored cores from previous drillholes were relogged and sampled. Emphasis was given to mapping alteration patterns and breccia pipes, and to the recognition of mineral zoning. At Anabama Hill, multiple bodies of granodiorites, micro granodiorite, porphyry and breccia pipes intrude into an older Ordovician granite (the Anabama Granite). Coincident, zoned hydrothermally altered breccia pipes and the copper and molybdenum mineralisation are now considered to represent the vent of a deep porphyry copper-molybdenum system similar to the Henderson and Mount Emmons deposits of Colorado. Earlier drilling completed by Asarco and the South Australian Mines Department has established the presence of low-grade Cu-Mo mineralisation associated with the intensely hydrothermally altered breccia pipes, but this drilling was relatively shallow and had concentrated on locating near surface ore-grade mineralisation. However, several pieces of evidence exist which indicate that both the breccia pipes and the hydrothermally altered rocks are the surface expression of a deeply buried porphyry system. They are: 1. The breccia pipes contain fragments of micro granodiorite which differ in texture from any outcropping granodiorite. This micro-granodiorite could represent a deep seated stock responsible for the mineralisation. 2. The Cu-Mo mineralisation occurs in quartz veins and vugs either within or radiating from the breccia pipes. The mineralisation is always associated with a strong development of quartz-muscovite alteration. This alternative product appears to have been formed by pneumatolytic-hydrothermal processes from an ascending volatile-rich residual solution. The volatiles have left behind abundant vesicles (amygdules) with alteration rims. This can be seen both within and around the breccia pipes. 3. The mineralisation and quartz-muscovite alteration are a a late stage pulsational event, overprinting earlier potassic-biotite and propylitic alteration zones. Consequently, Asarco now believes that what it sees both on the surface at Anabama Hill and in the drill core represents a chimney zone through which both breccia pipes and a late stage volatile-rich solution have vented. The size of the alteration halo and the presence of chalcopyrite and molybdenite is encouraging enough to want to deeply test this zone, since there is room within it to hold a 500 million tonnes plus copper-molybdenum orebody. One vertical diamond drillhole, 700 m deep, is recommended to be drilled at 18400N, 15700E.