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Deposit Synonyms
Greens South Extended; Greens Workings; Hamlyn; Iron Blow; Ml 5678; Mutooroo Consols; Mutooroo Copper Recovery Ltd; Mutooroo Extended; Mutooroo Metals; Mutooroo South; North Mutooroo; Osborne Workings
Mineral District
Mutooroo Copper
Deposit Summary
Cu-Co-Au mineralisation in shear-hosted lodes in host amphibolite. Production from 1887-1908 ~6,000t @ 7-19%Cu. Estimated resource 12.5Mt @ 1.53%Cu & 0.14%Co, 0.23g/tAu, 2.5Mt @ 20%S.
Deposit Description
MUTOOROO, Cu-Co-Fe-S mineralisation was mined from 1887-1953, with >15,000 tonne of oxide and sulphide ore recovered for production of 242 tonne of copper metal. Ore minerals included chalcocite, cuprite, malachite, chrysocolla, azurite, bornite, and atacamite, and primary sulphides, coarse grained pyrrhotite, pyrite (cobaltiferous), chalcopyrite in a gangue of quartz, goethite, and secondary silica. Numerous shafts developed over a 1.7km strike length on 3 main lodes trending NNW, dipping steep to 45W. The lodes consisted of a quartz-sulphide breccia developed in shear zones sub-parallel to schistosity in bodies of amphibolite/diorite, minor gneiss of the Willyama Supergroup.
30 diamond holes completed by BHP in the 1970s identified a resource of ~8.7Mt of sulphide ore at 1.9%Cu (non-JORC).
A 2007 re-evaluation of geochemical analyses by Havilah Resources identified a Cu-Co-Au-S-(Fe-Zn-Pb-Ag-Bi-As) association, in particular, a significant proportion of cobalt. Resource drilling of the top 200m of the lode zone confirmed mineralisation hosted by major NNE-trending shear zones, traceable for over 2km on surface. Resampling (2018) of historic cored holes from 1964 drilled by Mines Exploration confirmed continuity of Cu-Co-Au mineralisation at depth.
The sulphide lode system was of complex form, consisting of a main lode, and various footwall and hanging wall lodes that in aggregate varied from a few metres to >30m thick. A feasibility study was in progress (2009). Conclusions to date indicate a high net value for sulphide ore given recovery of Cu-Co-Fe, and 36% of S converted to sulphuric acid for a 500,000 tpa operation. Inferred resources (2010) were 13.1Mt @ 1.48%Cu, 0.14%Co, 0.23g/tAu, 2.5Mt @ 20%S (www.havilahresources.com.au) for ~700m of strike length, which is ~30% of the known strike length. In 2018 Havilah Resources sampling along the southern extension of the line of lode for a distance of ~1km returned anomalous Cu-Co values to maximum 0.16%Co, 0.02%Cu (Mutooroo South prospect)
Discovery Year
? 1887
Commodities
Copper, Gold, Cobalt, Sulphur
Ore Minerals
Argentite, Bismuthinite, Bornite, Chalcocite, Chalcopyrite, Copper, Galena, Gold, Sphalerite
Gangue Minerals
Jasper, Limonite, Magnetite, Pyrite, Pyrrhotite, Quartz
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