The Cosmo greenstone belt is one of the few remaining underexplored greenstone belts in Western Australia. Cosmo Gold Limited holds the entire greenstone belt under granted exploration licenses and exploration applications covering an area of ~640km2. The significance of the Cosmo Newbery project is that it is significantly underexplored and occurs in a region that has generated major gold deposits. To the east is the economically significant Yamarna and Dorothy Hills greenstone belts where Gold Road Resources (ASX:GOR) have Measured and Indicated Resources of 6.62 MOz Au, including the Gruyere gold mine with Measured and Indicated Resources of 5.8 MOz Au – see GOR announcement 12 February 2020. The Laverton greenstone belt to the west has historical production of around 12 million ounces of gold.
The Cosmo Greenstone Belt has analogous geological and structural features to these belts.
Key geologic elements of the orogenic gold mineralisation model are present within the project area, including Archaean Greenstone Belt lithologies, known gold mineralisation, a crustal-scale shear zone, felsic intrusions, and localised faulting and shearing.
Historic High Grade Gold Production
The majority of the greenstone belt (~75%) is obscured by colluvium and sand cover but is interpreted from airborne aeromagnetics to be ~50km long and 3-11km wide as shown on Interpretation map. Greenstone belt outcrop is largely restricted to an area immediately north and south of Cosmo Newbery where historic high grade gold workings are located demonstrating that the area is mineralized. Ore produced was transported 95km to the Laverton Battery.
Due mainly to Native Title access restrictions, and with the exception of limited reconnaissance in 2017, the Project area has been unexplored since 2002.
Negotiation of required Access Agreements with Native Title parties is complete and allows for the concerted exploration this large underexplored project requires.
Comprehensive exploration reviews, and aeromagnetic interpretation and target generation, have highlighted considerable untested potential within the Project area. This work also highlighted strong geological and structural similarities to the adjacent and economically significant Dorothy Hills greenstone belt a shown in Comparison Map below.
The Cosmo Newbery Project primarily has potential for gold mineralisation, with nickel-cobalt potential associated with an ultramafic unit near the west greenstone margin. Mafic complexes are not recognised at Cosmo Newbery but must be considered given successful exploration of nickel-copper-cobalt mineralisation at the neighbouring Mount Venn greenstone belt.
Large portions of the Project area are entirely unexplored, or tested by sampling that has obvious location, analytical and data quality issues. Systematic first pass exploration using geological, geophysical and geochemistry methods is required, including extensive project wide regional geochemistry.
Cosmo Newbery vs Dorothy Hills/Gruyere Comparison of interpreted solid geology – Southern Geoscience Consultants (2019)