A high amplitude, linear N-S trending magnetic feature, dubbed the Coffin Bay Magnetic Anomaly, and the recognition of basement lithologies analogous to those of metallogenically prospective late Archaean terranes in Canada, were the impetus for company exploration in the Coffin Bay - Mount Hope - Lock region of western Eyre Peninsula. Initially, work concentrated on the northern part of the magnetic anomaly lying within ELs 2007/2649, and comprised a review of available aeromagnetic data, the re-processing and interpretation of this data, acquisition of ground magnetics over a 4 km x 4 km grid, experimental calcrete sampling and MMI soil assays, and the drilling of 81 aircore holes for 5675 m. Basement lithologies encountered included mafic to felsic metavolcanics, BIF, calc-silicates, tremolite-marbles and various magnetite-rich metasediment types. U-Pb zircon dating confirmed probable late Archaean ages of ca 2720 Ma (inherited) and ca 2520 Ma (volcanic igneous). Bedrock sample assays returned highly anomalous Au, Pb, Zn, Cu, and Mo. Following the completion of TEISA aeromagnetic surveys over a wider area, and in consultation with the operators, PIRSA undertook a programme of 26 aircore holes in the vicinity of the earlier drilling, which included 16 diamond tails, for a total of 1800 m. This work, reported in PIRSA Report Book 2001/7, confirmed the general nature of the metavolcanic lithologies, and also returned anomalous values of Cu, Pb, Zn, Co and Ag. Upon entering into a joint venture agreement with the original licensees during July 2000, BHP Billiton (BHPB) then carried out detailed exploration in the area east from Mount Hope on EL 2662. Their work included ground magnetic traverses, aircore drilling (175 holes, total 11,922 m), Pb-isotope dating, orientation EM soundings, and limited heavy mineral sampling for diamond indicator minerals. While base metal anomalous areas were confirmed, the tenor and size were too small to be of interest to BHPB, who chose to withdraw from the joint venture agreement during August 2001. Parts of the project area were then surrendered by the remaining partners, with exploration presently continuing on the remainder.