Two adjoining areas located west-northwest of Leigh Creek are being explored as part of a regional search for possible economic Beltana-style zinc silicate hydrothermal replacement mineralisation hosted by brecciated Cambrian or Neoproterozoic...
Two adjoining areas located west-northwest of Leigh Creek are being explored as part of a regional search for possible economic Beltana-style zinc silicate hydrothermal replacement mineralisation hosted by brecciated Cambrian or Neoproterozoic bedrock carbonates. They contain part of the north-western extent of the Aroona Fault, which hosts numerous willemite occurrences including the Aroona mine and the Aroona II and Reliance deposits. Of particular continuing interest to Kelaray, in retaining its earlier tenure to some of the subject licence ground, is the covered bedrock area of intersection between the regional north trending Ediacara Fault and the north-west trending Aroona Fault, since both faults have acted as major mineralising fluid conduit structures. Much of EL 3193 Mount Parry is covered by a broad dune field, with little known outcrop. Historical drillhole data for the Mount Parry area indicates a significant thickness of cover materials overlying bedrock (100 to 250 m). No field work was conducted on the tenements during licence joint reporting years 1 to 3, because the joint venture partners' exploration 'effort' was said to be focussed on gaining further understanding of mineralisation controls that had been critical for forming the Reliance deposit located on the JV's adjacent EL 3111. During Year 4 of tenure, field geological reconnaissance activities were conducted on Myrtle Springs EL 3075, which were described as follows: - mapping and rock chip geochemical sampling at the Camel Flat deposit, including measuring mineralised bed thicknesses along the existing open major east-west trending trench, to assist in making resource estimate calculations; and - mapping and rock chip geochemical sampling of interbedded dolomite and magnesite strata at the Mount Hutton South deposit, and measuring the thicknesses of individual magnesite beds encountered on two cross-traverses, to assist in making resource estimate calculations. [Note: none of the resulting data were submitted to PIRSA] . During Year 5 of tenure, following the completion of reconnaissance work in 2007-2008, a preliminary investigation into the magnesite potential of renewed Myrtle Springs EL 4153 was undertaken, including correlation with linked resources known to exist on the northern portion of Copley EL 4211 (formerly EL 3111). At the Mount Hutton South prospect on EL 4153, a potential resource of the order of 10-20 Mt of magnesite ore was estimated. However, market factors affecting the viability of magnesite mining, including fluctuations in commodity consumption, production and price levels, had become highly volatile of late, and therefore it was clear that a closer study still needed to be made into the economics of mining these deposits. Given the JV's mandate for the discovery of additional zinc reserves in the Flinders Project tenements, magnesite exploration was considered a low priority. But to summarise the current state of knowledge, a report “Preliminary Investigation into Flinders Magnesite Potential” was written (attached herein). During Year 6 of tenure, the JV partners acquired a detailed, high resolution helicopter-borne magnetic and radiometric survey in February 2010, for a total coverage of 2544 flight line km, part of which was flown over the two subject licence areas. The aim of the survey was to identify structures and faults that have possibly channelled hydrothermal fluid flows which might have led to emplacement of buried base metal mineralisation. The survey was successful in identifying several magnetic anomalies showing obvious structural offset. Several of these targets are also coincident with surface haematitic alteration that was detected on regional Aster multispectral satellite imagery. During Year 7 of tenure, no field work was completed on either tenement. However, a review of the recently acquired airborne magnetic and radiometric survey data was made, to determine if those data could be used to differentiate between various mapped stratigraphic and lithological units. It found that extremely low total count radiometric signatures denoted the carbonate strata in the surveyed area, and since the known zinc silicate deposits in the region are hosted by limestone and dolomitic clastic sedimentary units, the JV partners hoped that recognition of this trait would in future enable them to do more focussed exploration. Likewise, this meant that other basinal outcrop areas having low total count radiometric signatures, that do not have exposed carbonate, might in fact be underlain by such prospective rocks, and therefore would also be exploration targets. During Year 8 of tenure, again no field work was completed on either tenement. In late 2011, Perilya purchased ASTER multispectral satellite imagery covering the entire Flinders Project area. The aim of the purchase was to attempt to highlight areas of iron enrichment that potentially could represent haematite-altered host rocks surrounding zinc silicate mineralisation. It was also hoped that carbonate and silica mineral reflectance spectra indexes could be used to provide a more detailed remotely sensed geological picture of vegetation-obscured outcrop within the area. Although the ASTER imagery appeared predominantly to just be displaying regional variations in the stratigraphy, an aureole of ferric iron anomalism was able to be identified in surrounding the Aroona NW prospect. During Year 9 of tenure, no exploration activities of any sort were undertaken on either tenement. During Year 10 of tenure, on 4/6/2013, EL 5336 Myrtle Springs was granted as a subsequent tenement to EL 4153, whilst on 3/11/2013, EL 4358 was reduced in size to 80 square km as part of the reduction in total project ground holdings required under the terms of the Flinders Amalgamated Expenditure Agreement. Exploration work was focussed on the Aroona NW target in EL 5336, which had now been further defined by interpretation of the ASTER imagery iron mineral species spectral ratios. A reconnaissance portable XRF spectrometric soil geochemical survey was completed there, with 705 readings taken over a 7 square km area along north-south traverses 200 m to 400 m apart. Eleven rock chip samples were collected at the same time for laboratory assaying. No significant base metal anomalism was identified at this target, nor was any significant bedrock haematitic alteration noted, and no Cambrian carbonate rocks were visible. No further work was planned the Aroona NW prospect, because it was now believed that the Aster imagery anomaly could be adequately explained by the presence of a local topographic depression containing ferruginised limonitic and manganese oxide altered younger sedimentary units. No work was undertaken on EL 4358. During Year 11 of tenure, EL 4358 Mount Parry was renewed as EL 5520, and its size was further reduced to 27 square km as part of the project ground's required total annual relinquishments. Field work was limited to doing a few days of reconnaissance traversing to try to identify the source of an aeromagnetic high response in the central portion of EL 5336; however, no obvious source could be identified. No field work was undertaken on EL 5520. During tenure Years 12 and 13 no work was done on either tenement. During tenure Year 14, no work was completed on EL 5336, while EL 5520 was surrendered early 2017 [See ENV 10553 CNO:2039805].