Utah's ongoing exploration for possible economic, buried stratiform Late Proterozoic copper orebodies at Kapunda and in the surrounding district has consisted principally of percussion and diamond drilling (66 and 9 holes respectively, totalling...
Utah's ongoing exploration for possible economic, buried stratiform Late Proterozoic copper orebodies at Kapunda and in the surrounding district has consisted principally of percussion and diamond drilling (66 and 9 holes respectively, totalling 12,619 m, of which 2302 m were cored). 9100 drill core and cuttings samples were taken for geochemical assay. In addition, surface sediment deposition studies, limited outcrop geological mapping, backhoe trenching of shallow subcrops, and trench wall channel sample and drill sample petrology investigations were undertaken. Most of this work was carried out adjacent to the historic mining field at Kapunda, but a secondary programme of rotary dragbit drilling (37 holes, total 986 m) was also performed along 5 traverses over the Allendale East Inlier to explore for geochemical anomalies and to try to locate the "Mine Series" stratigraphic section. Disseminated, subeconomic Cu and Zn sulphide mineralisation is widespread within the Tapley Hill Formation around Kapunda, especially close to the south-eastern edge of the township, and appears to be related to an indurated intra-Adelaidean palaeosurface encountered beneath weathered and transported cover, which has controlled the movement of groundwaters carrying mineralising solutions away from the fault zones mapped within the mine area. Preliminary studies on sulphur and carbon isotopes were initiated in an attempt to ascertain the origin of the sulphides and the carbonates present within the Kapunda "Mine Series" rocks, but the initial results were inconclusive, so more samples were submitted for geochemical and isotope determinations and an independent consultant's evaluation, which is still underway. Utah has concluded that its chances of proving up a viable copper orebody of adequate size and grade have receded, although not all of the identified drilling targets have yet been fully evaluated. Consequently, after nearly four years of activity as exploration manager it exited the joint venture agreement with licensee Northland Minerals, who shortly afterwards decided to allow tenure to lapse.
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