Mt Harcus EL3368 is located within the Palaeoproterozoic Musgrave Province. The region is recognised by PepinNini Minerals Ltd as prospective for magmatic Ni-Cu Sulphide mineralisation, platinum group metals, base metals, diamonds, and precious...
Mt Harcus EL3368 is located within the Palaeoproterozoic Musgrave Province. The region is recognised by PepinNini Minerals Ltd as prospective for magmatic Ni-Cu Sulphide mineralisation, platinum group metals, base metals, diamonds, and precious metals. The tenement consists of 4 separate blocks that cover 1607 square-km and is ~400 km west-northwest of Marla on the Stuart Highway. The blocks are referred to as Mt Moulden (western block), Mt Harcus (southern block), Mt Tietkens (eastern block) and Mt Cooperinna (northern block). Exploration licence 3368 was granted following the granting of a “Deed of Exploration” between Anangu Pitjantjara Yunkanjatjara (APY) and PepinNini dated 26/6/2005. The initial exploration focus of the company has been the nickel – copper sulphide potential of Giles Complex mafic / ultramafic intrusions in the Mt Harcus and Mt Moulden portions of the tenement. A large proportion of these areas are concealed by surficial sediment cover and the region is essentially unexplored. PepinNini Minerals has continually sought assurance from the Traditional Owners that its activities are approved through a process of regular dialogue with a key Traditional Owner Representatives from each of the work areas. During the first licence year, PepinNini’s exploration focus was on the Harcus and Purananja Intrusions; two significant mafic intrusives bodies within the tenements Mt Harcus and Mt Moulden blocks. Field work involved heritage clearance surveys, airborne electromagnetic surveying, ground electromagnetic surveying, surface geochemical sampling, mapping and RC drilling. No field activities were undertaken within the Mt Tietkins and Mt Cooperinna blocks. A helicopter borne HoistEM survey was flown during September and October 2005 across the Mt Moulden and Mt Harcus to look for potential conductivity responses associated with Giles Complex intrusions. A total of 2785 line-km were flown with 1407 km over Mt Harcus and 1378 km over the Mt Moulden block. The surveys clarified the distribution of conductive paleo-channels and resistive bedrock but is assessed to have been ineffective in penetrating below a depth of 75 m to test for bedrock conductors likely to indicate massive nickel and copper sulphide accumulations. Reconnaissance ground moving-loop electromagnetic surveying of selected traverses across the mafic intrusive bodies at Mt Moulden and Mt Harcus was completed in September and November 2005 by Outer Rim Exploration Services Pty Ltd. The survey utilised a Crone PEM instrument with a standard Crone receiver coil using a 100 x 100m moving loop at 50 m or 100 m centres. A total of 71.3 line-km of data was acquired over 23 travers lines from 806 station readings. Southern Geoscience were commissioned to review and interpret the data. The surveys identified a small number of weak conductive features. Palaeo-channels and other conductive sources have masked potential bedrock features in some areas. No significant conductivity responses indicative of large shallow massive sulphide accumulations was detected in the areas traversed. [Several geophysical consultant reports/memorandums, logistics reports and assessments are included within the report’s appendices.] Rock chip (79) and soil (101) sampling around the Harcus Prospect has revealed variable low-level copper and nickel anomalism associated with the intrusive body. The reconnaissance level survey was opportunistic with samples collected for geochemical or petrological analysis from areas approved by Traditional Owners. Rock chips sampled from the Harcus Copper anomaly returned results for Cu 4x higher than background, and Ni 3-4x higher than background. While a single rock chip sample from a gravel pit in Mt Moulden returned a value of 1051 ppm Ni, approximately 5x background. A total of 20 rock samples were collected for petrological examination, while 3 samples of fresh hypersthene gabbro and pyroxenite were collected for post-graduate petrophysical studies by Mathew Grey at the University of Adelaide, formal results of the study were not available at the time of reporting. Twenty-one RC drill holes for a total drill length of 3069 m (RC06HAR001 - RC06HAR014, RC06MTM001 - RC06MTM007), were completed to test a variety of interpreted structural, geophysical, and geological targets during April and May 2006. A single water bore was drilled on the Mt Moulden block to a depth of 47 m. Fourteen inclined holes were drilled proximal to the Harcus Intrusive, and 7 holes drilled around the Purananja Intrusion. A narrow intersection of massive primary sulphide accompanied with a broader zone of disseminated sulphide was intersected within pyroxenite lithologies at the Harcus intrusion. The sulphide occurrence is dominated by pyrrhotite but does contain accessory chalcopyrite. The intersection confirms the sulphur saturation state of the intrusion and the potential for massive sulphide accumulations elsewhere within the intrusive systems. During licence Year 2, exploration activities have involved gravity surveyings, ground magnetic surveying, soil auger sampling, and reconnaissance mapping. Work area clearance surveying was unduertaken in March 2007 for areas within the Mt Moulden block work area and activities were verbally cleared by the Traditional Owners with official written approval was received shortly thereafter. PepinNini is still awaiting formal written report regarding the Heritage Clearance survey undertaken in 2005 and despite repeated enquires and meeting with those involved throughout the reporting period, the reports remain outstanding. A detailed ground magnetic survey was undertaken in November 2006 across the Harcus Prospect with 77 travers lines for a total of 83.5 line-km surveying completed, using a Scintrex MP3 proton precession magnetometer with a sensor mounted on a 1.6m pole and readings of the magnetic field collected at 5m increments along each traverse. The data confirms the extreme negative dipolar magnetic anomaly directly associated with the gabbroic and pyroxenite Harcus Intrusion. Modelling of the magnetics suggest a steeply dipping to near vertical slab of reversely magnetised intrusive rock averaging a width of 300-350m. PepinNini commissioned Haines Surveys Pty Ltd to undertake detailed gravity surveys within the Mt Moulden and Mt Harcus blocks between 20/5-6/6/2007, with a total of 1014 station readings collected on variable intervals between 500 m and 50 m. Gravity surveying of the Purananja Intrusion (Moulden) has indicated the existence of a very large deep gravity anomaly which extends to the north of the Mt Moulden tenement boundary. Strong gravity and magnetic characteristics have been identified from the Harcus and Harcus NW Prospects which better define the geometry and distribution prospective Giles Complex Intrusions. A detailed geochemical soil auger sampling program was undertaken across the Harcus Prospect between November and December 2006. A total of 574 soil samples were collected using a hand auger at varying depths in from 15 cm in areas of sub crop to up to 2 m, at 50 m intervals along east-west traverses. Geochemical dispersion patterns in soils at the Harcus Prospect have revealed a large coherent 1.4 km x 350 m Cu-Ni anomaly and two secondary anomalous zones across parts of the Giles Complex mafic intrusion. These anomalous levels of copper-nickel are up to 9 times higher than background values. A secondary elongate zone of weakly elevated Cu-Ni extends 500-600m north of the main anomaly and may highlight a favourable zone for basement mineralisation paralleling the western intrusive contact. No field activities were undertaken within the Mt Tietkins and Mt Cooperinna Blocks of the exploration licence. During licence Year 3, PepinNini’s exploration activities involved an extensive diamond drilling program across the Harcus Intrusion and the Purananja Intrusion, along with downhole TEM on several holes within the Harcus block. Again, no field activities were carried out within the Mt Tietkins and Mt Cooperinna blocks. Between July 2007 and April 2008, PepinNini undertook a diamond drilling program of 13 HQ/NQ2 cored holes for a total length of 5228.49 m (DD07HAR001 - DD07HAR008, DD08HAR009, DD07MTM001, DD08MTM002 - DD08MTM004), with 4 holes drilled within the Mt Moulden block and 9 within the Mt Harcus block. A total of 1569 samples were collected and assayed from the thirteen boreholes. Maximum assay values were recorded in DD07HAR008, located within the northern Harcus intrusion. Minor intervals of massive and disseminated sulphides returned assay values of 0.31% Ni (211.9-212 m), 0.56% Cu (212-212.5 m) and 0.74% Cu (224.5-225m). An additional 10 samples were collected from hole DD08MTM003 within the Mt Moulden block for whole rock major- and trace-element analysis. Downhole electromagnetic surveys were completed on 6 of diamond cored holes within the Mt Harcus block by Outer Rim Exploration Services Pty Ltd. Only the Z component of surveying was completed, and no clearly defined anomalies of potential interest were identified. Four petrological studies on diamond core samples were commissioned, 3 to Pontifex & Associates Pty Ltd and 1 to Mason Geoscience Pty Ltd [detailed reports included within annual report]. Disseminated sulphides were present in all holes, confirming sulphur saturation occurred within the magmatic system. Included with the annual report was the detailed gravity survey results from the previous reporting period completed by Southern Geoscience Consultants Pty Ltd. The surveying identified several gravity highs within both the Mt Harcus and Moulden blocks. During licence Year 4, no field-based exploration activities were undertaken by PepinNini, with only a Heritage Clearance Survey of the Mt Cooperinna block and desktop studies including the evaluation and interpretation of geophysical data, petrophysical data and assay results from activities within the Harcus and Moulden blocks. The Tradition Owners for the region have been identified and a Work Program Clearance is planned for the following reporting period. During licence Year 5, no field-based exploration activities were undertaken within EL3368 during the reporting period other than the monitoring of rehabilitated drill sites, drill tracks and camp site. Traditional Owners within the Mt Cooperinna Block have been identified and Heritage Clearance Surveys are being negotiated.
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