Gold and copper exploration undertaken in an area of almost no outcrop (<1%) in the vicinity of the Challenger gold discovery on the north-western Gawler Craton, where the surface geology is predominantly aeolian sandsheets and pedogenic...
Gold and copper exploration undertaken in an area of almost no outcrop (<1%) in the vicinity of the Challenger gold discovery on the north-western Gawler Craton, where the surface geology is predominantly aeolian sandsheets and pedogenic calcrete crusts punctuated by low silcrete ridges, has proceeded via regional and infill calcrete geochemical sampling to identify gold anomalies which have then been tested by shallow bedrock RAB drilling. Selection of prospective structural positions has been aided by the ongoing interpretation of aeromagnetic data and Landsat TM imagery. Initial soil calcrete sampling at 1.6 km spaced centres spread across the entire licence area (327 samples), except for on the large salt lakes in the south-eastern corner, identified several gold-anomalous areas which were then infill sampled by collecting calcrete variously on 400 m x 800 m and 400 m x 400 m prospect grids, closing in to 200 m x 400 m or 200 m x 200 m sample spacings where needed (for a further total of 3293 samples). The best surface sampling results of 30 and 35 ppb Au came from infill sampling at Tomahawk prospect. During licence years 1 and 2 two campaigns of RAB drilling were undertaken at Indooroopilly Bore prospect (87 holes for a total penetration of 3569 m, plus another 47 holes for 1489 m). A maximum gold assay value of 1.3 ppm Au was obtained from 30-31 m depth in hole 96IPAR027, the basement lithologies being Christie Gneiss, granite and undifferentiated mafic rocks. Some chlorite alteration is associated with shearing in the northern part of this prospect. During licence year 3 follow-up RAB drilling was conducted at Indooroopilly Bore (57 holes for 2192 m : best intercept 1 m @ 0.54 g/t Au from 42 m depth in hole 97IPAR165), while first-pass RAB drilling was also conducted at Tomahawk prospect (37 holes for 1564 m) after acquiring 15 line km og ground magnetic profiles, and at Coopers Tank prospect (27 holes for 1094 m : best intercept 1 m @ 0.13 g/t Au from 34 m depth in hole 97CHAR2190). Minor regolith geological mapping and related rock chip sampling (7 samples) was also done. During licence year 8 first-pass RAB drilling was carried out at Chariot prospect (46 vertical holes for 2041 m, completed during July 2003 along 5 east-west traverses). No work took place on the subject Blowout tenement during all of licence years 4 to 7 and 9 to 10, owing to the concentration of Dominion's exploration activity on its adjoining Jumbuck EL 1971 / EL 2637 (for the purpose of advancing the Challenger mine development feasibility study).
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