Exploration for possible economic vein-style and structurally controlled gold with Adelaidean bedrock sediments in an area located south of Manna Hill township was conducted using low cost remote sensing, geochemical and geophysical methods. The...
Exploration for possible economic vein-style and structurally controlled gold with Adelaidean bedrock sediments in an area located south of Manna Hill township was conducted using low cost remote sensing, geochemical and geophysical methods. The subject licence was applied for to follow up previous rock chip gold geochemical anomalies identified by Australian Anglo American in gossanous quatrtz veined sandstones within the Tarcowie Siltstone. This unit is considered to be prospective for sediment-hosted gold deposits similar to those found in the historic Wadnaminga Goldfield. During 2008, 2009 and 2010, reconnaissance traverse soil sampling was undertaken using Innov-X portable XRF analytical equipment, when 567, 682 and 703 samples respectively were tested for a wide range of trace elements. Sampling coverage commenced at 400 m x 100 m grid spacing and was taken to a spacing of 100 m x 200 m or 150 m x 150 m. A consultant was engaged to review and interpret available regional geophysical data, and acting on his recommendation that more detailed coverage was needed for delineating the region of interest, licensee Panda Mining flew 8834.5 line km of new aeromagnetic / radiometric / DTM coverage across the Manna Hill Project acreage during April 2010, along north-south lines spaced 140 m apart, using a mean sensor height of 45 m above the ground surface. During 2010-2011, Panda Mining undertook ground inspections of remote sensing anomalies and collected 5 rock chip samples for assaying. During 2011-2012, an interpretation of the airborne geophysical survey was undertaken for Panda Mining by Southern Geoscience Consultants Pty Ltd. The licensee then made field visits to selected geophysical anomalies to map local geology and collect outcrop samples for assaying (30 samples taken). A follow-up soil sampling programme was conducted along traverses 100 m apart with 50 m sample spacing (122 samples). In addition, several field trips were made to the licence area by groups of Chinese geologists from the 106th Sichuan Geological Brigade, under an arrangement between the licensee’s major shareholder, Chengdu Di’ao Mining Energy Industry Co., and the Chinese geological survey. The visitors undertook geological mapping and rock chip sampling along traverses. During 2012-2013, Panda Mining resumed its desktop examinations of geophysical anomalies generated by previous work. From the revisit, plans were drawn up to conduct an extensive soil geochemical sampling programme addressing inferred buried metasomatic and porphyry style copper-gold targets. A work area clearance for a 5 square km area was obtained from local Wilyakali Native Title claimants in November 2012, to allow the licensee to perform ground-disturbing activities there. During 2013-2014, further field geological mapping and rock chip sampling (45 samples collected) was performed. Following receipt of the assay results, portable XRF spectrochemical scans were made as infill to previous FPXRF sampling, using a 100 m sample spacing (160 sites scanned). Encouraging rock chip results were returned from the south-eastern part of the tenement. A drilling programme, to investigate the subsurface gold and copper mineralisation potential associated with elevated geochemical values obtained by Panda Mining in the vicinity of the 1991 Passair drillholes, was planned for October 2014. During 2014-2015, further FPXRF soil geochemical sampling was conducted to follow up rock chip sample anomalies and to infill three previous XRF sampling grids down to 50 m sample intervals (2802 new sites scanned). As intended, some exploratory RC drilling was undertaken near Dodd Hill, of 20 inclined holes with a total penetration of 1592 m. The October 2014 drilling addressed three objectives: 1. to follow up on Passair's 1991 drilling which was not conclusive, but which had returned anomalous results for gold associated with the chilled margins of a dyke; 2. to target a magnetic anomaly detected both from a ground magnetic survey conducted by Passair as well as by Panda Mining's aeromagnetic survey conducted in 2010; and 3. to test the extensive calcrete-capped sediments developed on low-lying parts of the Benda Range, for possible supergene gold mineralisation occurring below the calcrete. Holes BEN002-BEN008 drilled this calcrete target, and found a consistent thickness of non-mineralised calcrete cover. The remaining thirteen holes were collared in Tarcowie Siltstone bedrock outcrops of strongly sulphidic black shales containing mainly pyrite and pyrrhotite with lesser chalcopyrite, and were designed to test either the magnetic anomaly or the dyke. The dyke was intersected twice (in BEN013 and BEN017), while most of the other holes intersected zones of pyrrhotite, which could be the source of the magnetic anomaly. The drilling returned some positive gold intercepts from the dyke and the many radiating quartz veins, ranging from 1-2 ppm Au sporadically, up to 7.8 ppm Au assayed in one x 5-metre composite drill cuttings sample (50-55 m in hole BEN013), which also returned 2.4 g/t Ag. Additional, more precise assaying of 1-metre cuttings sample intervals confirmed this tenor of mineralisation. No further work was done on the tenement over the succeeding 31+ months before the decision was made to fully surrender tenure.
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