A licence area located 20 km west-southwest of Port Lincoln, which covers the historically worked Uley graphite deposit and environs, was taken up to try to delineate sufficient mineral resources and, eventually, ore reserves of graphite in the...
A licence area located 20 km west-southwest of Port Lincoln, which covers the historically worked Uley graphite deposit and environs, was taken up to try to delineate sufficient mineral resources and, eventually, ore reserves of graphite in the Mining and Retention Leases and in surrounding similar country to the south, that would be suitable to feed a planned concentrator at Uley employing new proprietary design technology, and a planned product refinery to be built in another location in Australia. During August-September 2007, 25 vertical aircore holes totalling 709 m were drilled on EL 3414 plus one other 36 m deep hole on ML 5661, to investigate selected Sirotem, Input EM and IP ground survey anomalies that had been defined in earlier work done by CRA, and to provide fresh samples of graphite mineralisation to send off for chemical analysis, petrographic studies and preliminary metallurgical testwork. The following conclusions were drawn from the work undertaken: 1. There are a number of small to very large bodies of graphite-bearing rock on the Uley area tenements under option to Mikkira Graphite. 2. The graphite content (grade) of these various bodies is not known in sufficient detail to estimate mineral resources to JORC requirements. However, past drilling has clearly indicated that the grades are of a level to be economic, if all other parameters are met. 3. High to moderate grade graphite occurs in all target areas drilled in the aircore program. Below 10 to 15 m depth from the surface, the carbon-in-carbonate content of the graphite schist is less than 1%. Above these levels, it ranges up to nearly 5%. 4. Graphite flakes of size from <0.1 mm to over 2 mm occur in all areas which have been drilled. 5. The majority of flakes in the drill samples are not perfectly flat, but instead are slightly to somewhat more obviously curved. A very small number are strongly folded. 6. The zonation from a surface iron-rich zone, to carbonate zone, to clay zone, to weathered then fresh rock, described by John Keeling as being present at the Uley mine, also exists at all of the target orebodies so far drilled on EL 3414. 7. Within the carbonate zone, interlayer penetration and surface encrustations of calcite occur with the graphite. This may be removable with a dilute acid wash. The effect of this treatment on flake properties remains to be determined. 8. There is no obvious correlation between graphite grade and flake size, but the number of samples analysed to date is too small to permit a definite assessment. 9. The drill samples recovered from below the Main Road Pit on ML 5661 show that the normal carbonate-rich zone persists down to a depth of over 15 m. Visually, the flakes in this target orebody appear to be of good quality, although some are strongly folded. 10. The limited metallurgical testwork and the past operation of the processing plant have demonstrated that concentration of the graphite by flotation is technically feasible. No new work was performed on the subject licence during the ensuing four years of tenure (i.e. until the end of licence Year 7). On 5/1/2014, management responsibility for EL 4778 and the Uley Graphite Project passed from Mikkira Graphite to newly listed public company Valence Industries Operations Pty Ltd. During licence Year 8, Valence Industries conducted a data compilation and review of relevant previous exploration to identify targets adjacent to the existing graphite resource and via 3D modelling, to better delineate geophysical and geological features that might define ore zones. This careful work allowed the company to identify four meaningful exploration opportunities known as Uley 2B Pit, Uley 3 Pit, Uley 3 North Pit and Uley 3 South Pit, which are located on RL 66, RL 67 and EL 4778. During May 2014, geological mapping of the Tertiary Bridgewater Formation was undertaken to define its boundaries in the vicinity of the mining leases. This was done to give an understanding of the extent and characteristics of the regional aquifer as it occurs there. From early July to late August 2014, a Phase 1 appraisal drilling programme was performed on the Uley resource, comprising 40 x HQ3 diamond holes for a total penetration of 4052.8 m, put in along 5 traverses in the planned Uley 2 Pit area at a 25 m x 25 m hole spacing that was inclusive of existing holes. The programme infilled a known resource identified by geophysics in 1993 and partially drilled out in 1993 and 2011. Based on the then understanding of the geology of the mineralisation, all of the new holes were designed to be drilled at -60 degrees to an 090 azimuth. One-metre interval half drill core samples with visible graphite mineralisation were assayed for graphitic carbon, total carbon, and carbon existing as carbonate, and nine selected core samples were described petrographically in both thin and polished section. Using the additional geochemical data, Valence Industries during September 2014 calculated an updated JORC mineral resource estimate for Uley (now substantially increased relative to that prepared earlier by Coffey Mining for Strategic Energy Resources - see ASX announcement of 17/11/2012), and also a maiden Proved + Probable Ore Reserve figure of 2.035 Mt @ 12.9% gC (graphitic carbon), using a cut-off grade of 3.6%, which was released to the ASX in December 2014. During licence Year 9, between November 2014 and May 2015, a Phase 2 appraisal drilling programme was performed on the Uley resource, comprising 66 x HQ3 diamond holes for a total penetration of 6509.8 m, put in along 11 traverses in the planned Uley 2 Pit area at a 25 m x 25 m hole spacing. This drilling was designed to expand the geological interpretation provided by the Phase 1 holes into both the northern and southern edges of the target EM anomaly. Hole sampling and drill core analyses followed the protocols established the previous year, to build up a seamless dataset. In December 2014, Valence Industries released its maiden JORC 2012 Graphite Ore Reserve and an initial “Life of Mine” (LOM) forecast production schedule for its wholly owned Uley Graphite operations, and this set of estimates was updated by consultants Coffey Mining in May 2015 based on the Phase 2 drilling results (the texts accompanying the relevant successive announcements made via the ASX are appended herein). The new Proved + Probable Ore Reserve figure became 2.917 Mt @ 12.1% gC. A review which was made of historical geological data confirmed that the overall structure with in the Uley 1 Pit area consists of a north plunging antiformal fold system: features of this proven structure were extended southwards into the Uley 2 Pit area and were interpreted to suit the geological data from the Phase 1 drilling. During licence Year 10, in late January 2016, Quantum made a brief field trip to the Uley mine site to gain exposure to the geology via inspections of diamond drill cores, pit walls and outcrop. Further to this, preparations were made to assign geo-metallurgical domains to the May 2015 modelled graphite reserve within the Uley 2 Pit. By using existing assay data and performing geological logging of drill cores, Quantum was able to devise a “rule of thumb” to approximate the geo-metallurgical domains inferred to exist within the Uley deposit. However, without input from a full suite of assay / mineralogical data and supporting metallurgical testwork, the results can only be regarded as indicative. Grade tonnage curves for the May 2015 Measured and Indicated Ore Reserve in the Uley 2 Reserve Pit were plotted. During licence Year 11, during the reporting period 13th October 2016 to 12th October 2017, the company was subject to Deed of Administration and no exploration work undertaken. Exploration was expected to resume following the Annual General Meeting to be held in December 2017. Quantum Graphite Limited was relisted on the Australian Stock Exchange on 27th September 2018. During licence Year 12 no work was completed. Assay results from the companies earlier drilling program were released as a part of an announcement to the ASX on 30th November 2018.
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