An area centred ~45 km east-southeast of Hawker was taken up to explore the stratabound, epigenetic copper resource potential of historic small copper workings located along a NW trending fault zone disrupting Adelaidean metasediments of the Burra...
An area centred ~45 km east-southeast of Hawker was taken up to explore the stratabound, epigenetic copper resource potential of historic small copper workings located along a NW trending fault zone disrupting Adelaidean metasediments of the Burra and Umberatana groups, in the vicinity of surface mineral alteration spectral signatures that Copper Range had discerned when inspecting Aster satellite imagery. Another feature deemed to be of interest was an aeromagnetic anomaly in the south of the area, which BHP Minerals had explored during the 1970s but had not drill tested. During the first licence year, several identified prospects were tested by soil sampling and drilling. At Disraeli, soil sampling did not detect any surface anomalism near the historic workings, so no further work was planned there. At Emu, the abovementioned aeromagnetic anomaly was drilled with 2 inclined RC holes for 224 m (HWSRC001 & 002), but no base metal mineralisation was encountered. Soil geochemical sampling (78 samples) conducted there also produced negative results. It was concluded that the presence of a magnetite and hematite-bearing siltstone as seen in drill chips sufficiently explained the magnetic anomaly, so no further work was warranted. At Turkey, soil geochemical sampling identified a possible buried extension of a mineralised shear that had been seen in shallow pits on the old workings. A single inclined RC hole positioned to test this buried target (HWSRC003 to TD 58 m) intersected 2 m @ 5500-6100 ppm Cu below 56 m downhole, from very fine disseminated mineralisation in the form of chalcopyrite weathering to chalcocite within quartz veinlets in siltstone. The hole was terminated prematurely due to risk of the drill rods bogging in the black dolomitic siltstone, and so did not reach the predicted position of the shear. Follow-up drilling was deemed necessary to evaluate this copper occurrence. At Dodo (formerly called Black Hill Bore prospect) initial rock chip sampling returned elevated copper values which appeared to be associated with widespread fluid alteration of the bedrock. However, follow up sampling (26 samples) was not able to emulate these results. It was decided that to determine if a copper anomaly exists, soil sampling traverses should be made over the Aster alteration anomaly and across the fault seen to be present on the prospect. At Falcon, a zone of oxidising alteration was recognised from Aster satellite imagery which appeared to have overprinted previous reduced (carbonaceous) alteration. The redox boundary is a prospective zone, untested to date. During licence Year 2, Copper Range conducted a review of past exploration reports, and made reconnaissance visits to outcrops of Holowilena Ironstone strata where it undertook rock chip geochemical sampling (24 samples) and geological mapping, as part of assessing the formation's iron ore potential. The Holowilena Ironstone comprises red–purple hematitic silty shales with interbedded diamictites, and is split into two units, the ‘hematitic siltstone unit’ and the ‘Pualco Tillite unit’. The area of its outcrop on EL 3643 strikes at 50 degrees NE and is ~3 km in length. The southern end of the formation may continue buried beneath cover, whereas its northern end is truncated by a large fault. Copper Range identified a high grade iron rich horizon ~40 m wide having an average iron content of +45% Fe as indicated by FPXRF readings; however, this horizon may not persist along the entire length of the ironstone outcrop. Impurities such as phosphorous are higher than the acceptable levels, however, Copper Range suspected that superficial weathering may have concentrated them at the surface. During licence Year 3, no field work was done. Plans were made to sample all 3 km of strike of the Holowilena Ironstone outcrops. The prospective horizon is ~30 m wide and has an apparent sub vertical dip. During licence Year 4, systematic rock chip sampling of the Holowilena Ironstone (155 samples) was undertaken, and preliminary metallurgical testwork was completed on two bulk samples of it. Analytical results from the rock chip sampling confirmed the field observations, namely, that higher grade material (+35% Fe) has a strike extent of ~2.3 km and that particular bed varies from 10 to 30 m wide. Recessively weathered units are present, and these could represent higher grade goethitic material. The two bulk samples were taken in order to determine whether the 30-40% Fe material could be simply upgraded to a +60% Fe product by grinding. However, results of the liberation/beneficiation tests were disappointing, as no upgrading of iron content was achieved with different grind sizes. No other work ensued on the subject licence during the next three years, before a decision was made to allow its tenure to lapse.
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