Exploration for Challenger - style vein gold deposits within concealed Archaean basement has been carried out in two licence subareas located on the northern part of the Commonwealth Hill pastoral lease, under a joint venture between the principal licensee Pima Mining / Kelaray (later re-named Argonaut Resources) and Minotaur Gold (later re-named Redport), acting in conjunction with lesser consortium partners. However, the only significant field work done on these two areas was completed in the first two licence years: thereafter only reviews of the newly acquired data and office assessments of competing exploration priorities have ensued. Work commenced in June 1998 with the flying of a low level aeromagnetic/radiometric survey across the entire tenement, along north-south lines spaced at 100 m, with east-west tie lines every 1 km ; the airborne sensor height was 40 m. Next, a programme of regional calcrete sampling was carried out (540 samples) to follow up previously reported surface gold anomalies, to 8 ppb Au, found by the Resolute/Dominion joint venture, who had sampled on a 1.6 km x 1.6 km grid. Minotaur Gold then did detailed, 50 m x 50 m infill calcrete sampling (934 samples) to confirm coherent anomalies. 42 (~8%) of Minotaur's first pass regional calcrete samples returned anomalous gold (>=5 ppb), while 456 (~49%) of the infill samples did likewise. In licence subarea 'B', a 2200 m long zone of anomalous gold was defined along the eastern margin of a major NE-trending magnetic unit, that contained discrete peaks of up to 59 ppb Au. A second anomalous zone also lay along the north-western side of this magnetic feature, being 800 m long with peaks reaching 38 ppb Au. The magnetic feature at Aurora Tank prospect is interpreted to be a shear zone in the basement, which could be a north-easterly extension of the gold-mineralised Mars prospect discovered by the Commonwealth Hill partners on their adjoining EL 2595. That prospect had so far yielded a best RC drilling intercept of 4 m @ 2.0 g/t Au from below 112 m depth. The two anomalous gold-in calcrete zones at Aurora Tank were profiled with ultra-detailed ground magnetics run over seven lines, before the same lines were fence RC drilled to an average depth of 150 m in May 1999 (17 holes totalling 2468 m) to test the gold potential in bedrock. The RC drillholes were put in at 60 degrees inclination towards 315 degrees (AMG), on about a 70 m spacing, with the aim of intersecting any NNE-ENE trending structures and also the lithological contacts between magnetic and non-magnetic units, since both were considered to be important controls on possible primary Archaean gold mineralisation. A best drillhole mineralised intercept of 12 m @ 0.31 g/t Au and 390 ppm As below 100 m depth, including 4 m @ 0.682 g/t Au from below 104 m depth, was recorded from hole RCAT8 drilled on Line 2. Subsequent fire assaying of the mineralised drill cuttings samples returned 1 m @ 0.96 g/t Au from below 106 m depth. The surface 59 ppb gold-in-calcrete peak directly overlies this bedrock gold intersection. The low grade primary gold mineralisation is characteristically hosted by garnet-poor, non magnetic quartz-feldspar-biotite Christie Gneiss having coarse grained K-feldspar-quartz(-biotite) pegmatitic veining. On the opposite side of the target magnetic anomaly, drillhole RCAT13 on Line 4 recorded an average gold assay of 0.1 g/t Au extending over its entire 150 m hole length. Thus anomalous gold occurs throughout the saprolite, while beneath the supergene zone, an intercept of 20 m @ 0.46 g/t Au and 206 ppm As was found below 116 m depth, including 4 m @ 1.6 g/t Au and 650 ppm As from 120 m depth. Although the drilling carried out at Aurora Tank prospect returned only low to moderate gold grades, hosted by relatively thin, irregular and near vertical pegmatitic stringer veins emplaced within gneissic basement, the limits and the extent of the gold mineralisation have not been fully disclosed (since both RCAT8 and RCAT13 lay at the end of their respective drilling fence lines). The licence joint venturers therefore hope that potential remains for the discovery of large, high grade mineralised pods on or near the shear structure, which limited additional drilling could discover. As well, a blanket of secondary gold mineralisation is interpreted to lie on the fresh-weathered bedrock interface, presenting a favourable and easily drilled target. The presence of significant other gold exploration prospects in the Commonwealth Hill tenement package (Golf Bore, Campfire Bore, South Hilga, Typhoon, Monsoon, Mainwood and Birthday) means that ongoing gold exploration will probably further investigate these and portions of the Aurora Tank prospect using modern geophysical and geological techniques that were not available to previous explorers.