The Outalpa (EL 3472) licence area, comprised of two separate sub-blocks respectively centred ~30 km north-northeast and ~45 km north-northwest of Manna Hill, is one of five adjacent tenements held by PepinNini Minerals within the eastern Adelaide...
The Outalpa (EL 3472) licence area, comprised of two separate sub-blocks respectively centred ~30 km north-northeast and ~45 km north-northwest of Manna Hill, is one of five adjacent tenements held by PepinNini Minerals within the eastern Adelaide Geosyncline close to where it abuts the Curnamona Province. This boundary region has long been thought to have a highly favourable geological and structural setting for metallogenesis, and was recognised by grant licensee PepinNini Minerals (PepinNini) as being prospective for stratiform Pb-Zn-Ag, stratiform Zn-Pb, strata bound Cu-Au, iron oxide copper gold (IOCG) and Tertiary roll-front uranium styles of mineralisation. During the first licence year, PepinNini undertook a compilation and review of previous exploration data, and in October 2006 made a reconnaissance visit to the Black Hill area of the licence, where it performed geological mapping and collected 3 grab rock chip samples for assaying. These samples returned low copper values. However, this prospect was considered to occupy a highly favourable geological and structural setting where a major north-west trending demagnetised zone was interpreted to represent a faulted contact between Mesoproterozoic basement and Neoproterozoic Adelaidean metasediments. Anomalous surface copper values (maximum 3000 ppm Cu) which had earlier been detected there supported the model of Black Hill prospect acting as a focus and conduit of mineralised fluids. In addition, this area was regarded as having potential for unconformity related uranium deposits, because it was noted that outcropping Mesoproterozoic metasediments in the vicinity of Black Hill express uranium channel anomalism in regional airborne survey radiometric data, and thus could have acted as proximal sources for accumulations of such mineralisation. Later on, a proposal was submitted to PIRSA for the grant of PACE Initiative Year 4 collaborative drilling subsidy funds to help with testing of an IOCG-U or possible unconformity style uranium target at Black Hill. During licence Year 2, no work was done owing to a farm-in process that was conducted with Sinosteel Corp. of China, plus the need to meet other very high spending commitments at the nearby Crocker Well uranium project on EL 3278. The PACE drilling proposal intended for execution in 2007 was not approved. The same management reason for a persistent restriction in activity applied during licence Years 3 and 4. Joint venture operator SPCM performed some detailed 3D modelling of available geophysical data to assist with generating drill targets. During licence Year 5, an interpretation of airborne geophysical data was commissioned in mid-2010 from Southern Geoscience Consultants (David Isles) and a comparable regional structural interpretation was commissioned from GeoInterp (Leigh Rankin). Two possible drill targets associated with significant structures were identified which appeared not to have been drilled previously. Interpretation of aeromagnetic data identified extensive linear magnetic anomalies interpreted to represent the Adelaidean Braemar Ironstone member of the Pualco Tillite, in particular within the south-eastern sub-block of the tenement. The Braemar Ironstone was considered to be highly prospective for magnetite iron ore. Studies of alternative access routes which could be used within the tenement to service a planned uranium mine development were undertaken as part of the Crocker Well Bankable Feasibility Study. Existing water bores within the tenement were tested for yield quantity and quality to determine their suitability for supplying water to such a major development. During licence Year 6, on the subject renewed EL 4749, no work was done. During licence Year 7, in September 2012, a small part of the western sub-block of EL 4794 was overflown as part of a detailed helimag survey, the majority of which was flown on the JV's adjacent EL 4965 Mount Victor. Only about 100 line km of new aeromagnetic data were acquired on EL 4794 along north-south flight lines 100 m apart, using a towed sensor bird maintained at a 30 m mean terrain clearance height. It appeared from these data that the Braemar Ironstone does not extend into this part of the licence area, as formerly had been interpreted using older, less reliable magnetic data. Also, the size and intensity of other, non-linear magnetic anomalies became downgraded by the new coverage. During licence Years 8, 9 and 10, no work was done. Exploration activity was centred on the licensee's adjoining tenements. During licence Years 11 and 12, ongoing compilation, review and assessment of previous exploration data, regional aeromagnetic interpretation and target generation continued. Exploration programs and data interpretation has identified prospective targets within the tenement area. Future exploration programs will aim to test these targets as well as determine the prospectivity of the Braemar Iron Formation within the tenement area to host a significant magnetite iron ore deposit. No on-ground fieldwork took place.
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