Ravensthorpe Joint Venture Aerodrome Project
Introduction
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The Ravensthorpe project is located at Ravensthorpe, covering the under-explored Cocanarup ultramafic unit. Other ultramafic belts in the Ravensthorpe area are nickel sulphide endowed, hosting the RAV8 mine and other RAV deposits.
BHP Billiton have commenced construction of the Ravensthorpe Nickel Operation lateritic nickel treatment plant.
Latest Development by Pioneer
Pioneer has announced a joint venture with Galaxy Resources Limited whereby Pioneer may earn a 75% interest in the Aerodrome project.
A detailed aeromagnetic survey is planned. This will be followed by reconnaissance soil geochemistry.
Project Summary
Geological Setting
The Ravensthorpe greenstone complex resembles a north-westerly pointing chevron comprising three geologically distinct geological Terranes; the western Cocanarup; central Ravensthorpe and easterly Carlingup Terranes.
The Cocanarup Terrane comprise mainly meta-sedimentary rocks but also meta-mafic and ultramafic rocks. The Terrane is bounded by the Chidnup fault which separates it from the Carlingup Terrane; and a deformed contact with the Ravensthorpe Terrane.
The Aerodrome sector subdivision (northern Cocanarup Terrane) comprises mainly meta-sedimentary rocks interleaved with ultramafcs, amphibolite and gneiss. The Cocanarup differs from the Carlingup Terrane by the abrupt near-absence of BIF.
The Carlingup Terrane comprises metamorphosed mafic and ultramafic rocks together with metasediments including BIF, and minor felsic metavolcanic rocks. The rock package is folded to form the Maydon Syncline, with stratigraphic units including the Bandalup ultramafics, Maydon basalts, Hatfield formation and the Chester formation. The Cocanarup and Carlingup formations are juxtaposed at the "Chevron" apex.
The Central triangular area contains the Ravensthorpe Terrane, which contains abundant metamorphosed tonalite and calc-alkaline volcanics (basalt, andesite, dacite, minor rhyolite).
Exploration Activity
The Aerodrome project covers ultramafics which occur in the western sector of the Cocanarup Terrane. These are represented by predominantly talc-serpentinite with minor chlorite.
In this western belt, the greenstones are geochemically and lithologically similar to the eastern Carlingup Terrane rocks which are host to the Rav 8 Ni-Sulphide deposit currently being mined by Tectonic Resources Ltd, whose original published resource of 206,000 tonnes at 5.49% nickel has been significantly exceeded since operations have progressed. The Bandalup Ni-laterites being developed by BHP Billiton has a global resource of 253M tonnes at 0.8% Ni and 0.03% Co between three main areas.
The exploration record for the area is scant, however Falconbridge in 1974 explored the northern tenement area, (North of the Albany-Esperance Highway) referred to as Mt Short, and identified through soil geochemical sampling many anomalous assays in excess of 1500ppm nickel.
