Deposit Synonyms

Elizabeth Creek; Lake Windabout; Mount Gunson

Mineral District

Mount Gunson Copper

Deposit Summary

black shale-hosted Cu mineralisation of Tapley Hill Formation at depth 60-70m. Mineralisation controlled by disconformity at base of Whyalla Sandstone. Resource estimate (2000) 19 Mt @ 0.96%Cu, 0.05%Co & 10g/tAg.

Deposit Description

WINDABOUT, black shale hosted copper-cobalt-silver mineralised deposit intersected in drill holes at a depth of 55-85 m in 1977 during stratigraphic drilling to outline the sub-surface margin of the Tapley Hill Formation. Mineralisation was controlled by the Marinoan disconformity at the base of the Whyalla Sandstone, where the principal host was a permafrost breccia horizon on the upper surface of the black dolomitic shales of the Tapley Hill Formation. base metal sulfides formed through the replacement of diagenetic pyrite. Copper sulphide mineralisation comprising chalcocite, bornite, chalcopyrite, covellite, pyrite, carrolite, galena, sphalerite in gangue of dolomite, clay/sericite, quartz, and siderite as a cement in more porous dolarenite clasts in the breccia, and in dolarenite laminae in the underlying black shale. Gunson Resources Limited in 2000 had defined an indicated resource of 18.7 million tonne @ 1% Cu, 0.05% Co and 10 g/t Ag in a flat-lying zone about 2,000 m long EW by 1000 m wide NS, and 2-8 m thick, average 2.5m, and below 50-80m of cover sediment. The body dips ~5NW. Historically the inability to separate cobalt and silver from copper concentrates has impinged on the ability to realise any commercial value on the contained Co and Ag. Gunson Resources was pursuing avenues to fund research on processes to economically separate Co and Ag. In 2017 Gindalbie Metals completed further drilling to announce an updated resource in January 2018 of 17.67 Mtonne at 0.77%Cu, 492ppmCo, 8g/tAg at Cu Eq cutoff >0.5%.

Discovery Year

? 1977

Commodities

Copper, Silver, Cobalt, Zinc

Ore Minerals

Argentite, Bornite, Carrollite, Chalcocite, Chalcopyrite, Covellite, Galena, Sphalerite

Gangue Minerals

Clay mineral, Dolomite, Pyrite, Quartz, Sericite, Siderite

? Stuart Shelf

Pernatty Upwarp where Neoproterozoic strata thin out. Eroded wedge-out of the Tapley Hill Formation black shale. Mt Gunson deposits lie within corridor defined by this margin and wedge-out of Whyalla Sandstone. MG14 dyke and major fracture zone it occupies may provide conduit for mineralising fluids.