The subject licence, located approximately 60 km south-east of Leigh Creek, forms part of a much larger tenement package currently being explored by Perilya, primarily looking for zinc silicate mineralisation similar to the Beltana deposit,...
The subject licence, located approximately 60 km south-east of Leigh Creek, forms part of a much larger tenement package currently being explored by Perilya, primarily looking for zinc silicate mineralisation similar to the Beltana deposit, although the area is also regarded as quite prospective for lead-zinc sulphide and copper mineralisation. A large anticlinal structure trends NW-SE across it, and is cored by Cambrian limestones of the Wilkawillina Formation and flanked by Proterozoic quartzites and sandstones of the Rawnsley Formation. The remaining two separate portions of EL 4622 have recently been fully surrendered in partial fulfilment of the terms of the Flinders Ranges Project tenement group's 2014 Amalgamated Expenditure Agreement (AEA) renewal period. On the now surrendered remnant licence ground, prior to 2014, targets were primarily selected based on Aster satellite multispectral remote sensing data covering the Flinders Ranges region that was purchased by Perilya in 2011. Aster quartz ratio index images (relevant example provided) were used to determine the extent of carbonate strata in the licence area, while Fe-ratio images (ditto) were used to identify potential haematite alteration. During 2014, reconnaissance pXRF soil sample spectrometric scans and rock chip geochemical sampling were completed over a belt of Cambrian strata trending east-west across EL 4622, referred to as the Angepena East target. Although regional geological maps show that Cambrian aged rocks are extensive here, Aster quartz ratio index images suggested a more limited distribution. However, it was thought that the Aster - detected signal continuity was probably obscured by significant vegetative cover, which particularly hampers the iron ratio images. Instead, Perilya was able to discern from the geological map stratigraphic boundary pattern within the target that a possible fault bounded ‘rift/subsidence’ structure may have offset strata, which could provide a conduit for increased fluid flow and thus favour the deposition of base metal mineralisation. In late November 2014, 949 pXRF soil scans were made along ~9 km strike length of Cambrian strata. A nominal 1 km traverse spacing was used, with more closely spaced scanning sites occupied if outcrop alteration or significant rock structures were observed. In some places steep topography prevented the completion of pXRF traversing. 33 grab rock chip samples were also collected during the pXRF traversing to submit for laboratory assaying, for data checking purposes. The pXRF scans produced disappointing results. Maximum readings of 816 ppm Zn and 103 ppm Pb are considered to be much less than what would indicate proximity to a significant zinc silicate deposit, and copper readings were also low, with a maximum of 146 ppm Cu. The rock chip assay values also proved disappointing. Weak arsenic anomalism was identified near workings of a former barite mine, but no other significant zinc pathfinder element anomalism was found.
More +