Hillgrove updates West Papua copper/gold project
Tuesday, November 16 2010 - 02:21 AM WIB
Recent exploration activities have included ongoing channel sampling, geological mapping and remodelling of geophysical data in preparation for diamond drilling.
Exploration Results
Surface channel and rock chip sampling within the West Delta prospect continued over the past two months. Assay results from this work have confirmed the presence of widespread, anomalous copper mineralisation. Higher copper values appear to relate to structural features such as faults and jointing, with lower grade values relating to widespread hydrothermal alteration and associated disseminated copper mineralisation.
Geological mapping around the Green Cliffs Breccia target area has identified a zoned hydrothermal alteration system extending over several square kilometres, centred on computer modelled magnetic highs. Zoned alteration is consistent with the interpreted presence of a shallow, buried intrusive complex thought to be the source of anomalous copper values identified in channel sampling.
A central potassic altered zone mapped at the West Delta prospect is associated with anomalous copper values in soils and a single historical rock chip value of 3.7% copper. This is surrounded by a broader phyllic alteration zone, characterised by strong silica alteration grading into clay-dominant zones of argillic alteration. Boulders of advanced argillic alteration are found along numerous ridge tops indicating that a large sulphide-rich lithocap had covered the area but has subsequently been eroded off. The patterns of alteration seen at West Delta are similar to that seen in copper-gold porphyry systems throughout the circum Pacific and the level of erosion indicated by the remnant lithocap points to an intact porphyry system at shallow depths below the prospect area.
Channel sampling was undertaken almost exclusively within the mapped potassic and phyllic zones and assay results of low grade copper mineralisation are consistent with a conventional model of porphyry copper mineralisation. Mapping results indicate that a larger zone of potassic alteration is likely to exist at depth, with associated modelled higher grade copper mineralisation.
Historical drilling within the West Delta prospect was wide-spaced, limited and shallow, and appears to have tested only the outer phyllic alteration zone. Future drilling will target inner potassic alteration where better copper grades are interpreted to have formed.
Reprocessing of historical airborne magnetic data using the latest 3D geophysical modelling software has identified numerous magnetic bodies at depth. Recent mapping infers these magnetic bodies relate to late-stage intrusive complexes, which can be associated with porphyry copper mineratisation. Modelling has highlighted clusters of higher magnetic bodies located beneath mapped hydrothermal alteration and associated anomalous copper values. Ongoing mapping, structural interpretation and surface sampling geochemistry will provide a framework for ranking targets for drill testing.
Commenting on these results, Hillgrove Managing Director Drew Simonsen said ?These results reflect the steady progress towards building a 3D picture and postulating a model of the mineralisation at Bird?s Head. Progress is slow but steady, driven by the challenging terrain and the need to work closely with the local communities, from where we derive much of our workforce.?
?All of our work to date points to multiple porphyry targets within our license areas. The assay results to date are very encouraging and the next stage is to undertake a diamond drilling campaign, for which we are currently requesting tenders. Subject to availability and weather, we are hoping for first results towards the end of the first quarter, 2011.?
?The important and primary Green Cliffs Breccia target sits outside Hutan Lindung (Protection Forest) and is accessible for drilling. However, several of the identified porphyry targets sit within Hutan Lindung forest reserve. Hillgrove is currently seeking permission to undertake drilling of those targets within Hutan Lindung, in consultation with local and national authorities.? (end of edited release)