A tenement in the Coulta district of south-western Eyre Peninsula has lately been explored by International Metals, after its prior research had outlined seven areas there as being of prime interest in a search for Archaean greenstone units which...
A tenement in the Coulta district of south-western Eyre Peninsula has lately been explored by International Metals, after its prior research had outlined seven areas there as being of prime interest in a search for Archaean greenstone units which potentially might host nickel, gold and base metal deposits. The company had interpreted these features as representing part of the greenstone sequence reported as existing to the north of its tenement, where other companies' earlier drilling of similar magnetic features in the Mount Hope area had encountered a sequence of mafic and felsic seafloor-extruded volcanic rocks with interlayered magnetite-rich pelitic sediments. These units had been termed the Hall Bay Volcanics, and they are considered prospective for finding volcanic-hosted massive sulphide deposits and gold deposits. During October 2006, UTS Geophysics was contracted by InterMet to undertake a detailed low level aeromagnetic/radiometric/digital terrain model (DTM) survey over EL 3314. A total of 11,632 line km were flown along lines 100 m apart. The new aeromagnetic data highlighted a series of N-S trending magnetic units, which were interpreted to represent possible mafic extrusives or iron-rich units of the Hall Bay Volcanics which could be similar to those drilled in the vicinity of Mount Hope. Selected anomalies were confirmed with ground magnetic traverses, before the licensee made application to PIRSA for a grant of PACE Initiative Year 3 drilling project subsidy funds to assist with its exploration. The application was approved, and $50,000 was paid to Intermet under the terms of project contract DPY3-24 to help with the work. In its initial test of these targets, InterMet drilled 22 holes totalling 609 m during November 2006. The original plan was to drill a mixture of rotary mud and aircore holes, but difficulties arose with aircore drilling due to hign groundwater influx, plus an excessive drill bit failure rate, that prompted a change to RAB techniques to achieve the aims of the programme. Due to the difficult drilling conditions, this drilling failed to find any lithologies which would explain the aeromagnetic data. Modelling of the magnetic data showed that the magnetic features lie between 50-90 m deep, but the Phase 1 drilling failed to penetrate this deeply. Nevertheless, some notable results were obtained from the drilling: Hole COU003 - 51 ppm Ag 38-41 m Hole COU006 - 481 ppm Cu (5-6 m); 324 ppm Zn (5-6 m); 1076 ppm Co (6- 10 m) Hole COU009 - 3.9 ppb Au (8-12 m). During January-February 2007, a second phase of drilling was undertaken with an RC rig, aimed at successfully drilling deeper to reach the magnetic features outlined by the aeromagnetic survey. Ten holes (COU023-032) were completed for a total penetration of 680 m. All of these RC holes penetrated granite/gneiss interpreted to represent Wangary Gneiss having variable magnetite content. Best results from this drilling programme included: Hole COU031 - 0.22% Zn, 442 ppm Pb (68-72 m) Hole COU031 - 583 ppm Zn, 231 ppm Pb (72-76 m) Hole COU031 - 310 ppm Zn, 124 ppm Cu (76-80 m) Hole COU031 - 814 ppm Zn, 150 ppm Pb (80-84 m). A joint venture agreement with WCP Uranium was signed by the licensee in October 2006, whereby that partner could earn up to an 80% interest in any palaeochannel uranium discoveries made on EL 3314, after spending $1.5 million over four years on such a search. WCP began its work in mid-2007 by conducting groundwater sampling from water bores for multielement analysis (108 samples). The results suggested that dissolved uranium present in the local groundwater might be coming both from leaching of uraniferous minerals in Lincoln Complex felsic igneous basement, and from sediment-hosted accumulations previously deposited from fossil groundwaters. During January 2008 the farminee contracted Geosolutions to acquire the 1090.8 line km Wanilla TDEM Survey, flown at 400 m NW-SE line spacing with a 35 m sensor loop average ground clearance height. The survey data showed a weakly conductive body in a position that coincides both with its earlier detected groundwater uranium (to 47.9 ppb U) and aerial radiometric uranium anomalies. WCP felt that this observation deserved further investigation, but did not proceed further in this regard, instead deciding to exit the JV during late 2009.
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