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Deposit Synonyms
Area 128; Beltana South; Ml 4369; Ml 4370; Ml 4371; Mpl 85; Puttapa; Red Rocks; Rl 5; Rl 6
Mineral District
Beltana - Aroona Zinc
Deposit Summary
epigenetic, structurally controlled deposit of willemite in host Wilkawillina Limestone. Resource ~863,000t at 38% Zn, and 2.2% Pb (1974 - pre-mining). Production from 1977-2009 ~399,300t zinc product.
Deposit Description
BELTANA, mine developed on an epigenetic, structurally controlled deposit of willemite, with a resource of 972,000 tonne at 29.8% Zn, and 2.2% Pb (1974 - pre-mining). Later estimates suggested a pre-mining resource of 1 million tonne (Mtonne). Host rock is the fossiliferous Wilkawillina Limestone. The mine is located E of an anticlinal basement high of Willouran Callana Beds, and 2km S of the prominent Norwest Fault, and adjacent to the NS-trending Beltana Fault. The deposit is associated with low-angle NW-verging thrust structures. The principal ore mineral is willemite, also smithsonite, coronadite, hedyphane, and mimetite. Ore texture is complex from massive, red amorphous willemite, multiphase breccia, crustiform and colloform, fine laminates, radiating clusters, with lead mineralisation as fracture and void fill. The associated rock is intense hematite-dolomite altered. The footwall is brecciated. Hydrothermal dolomitisation, hematite and low-grade zinc occur as an alteration halo, with radius up to 400m around the deposit, less intense up to 1km distant. A broader dolomite halo extends for several km. The current model for origin of the ore suggests a structurally controlled epigenetic deposit style. Grubb (1972) inferred willemite was deposited from hot saline fluids at temperatures >250C.
Anaconda located the Beltana deposit via stream sediment sampling in 1967, with a peak of 300 ppm Zn observed. EZ gained tenure of the area in 1967, and mining operations commenced in 1974. Subsequently Pasminco took over the project, and mined the deposit on a campaign basis for recovery of 347,000 tonne at 38%Zn. Perilya Limited had an option over the project, and defined further resources beneath and south and south-east of the current pit design, and at near mine locations at the Red Rocks, Beltana South and Area 128 prospects. Workings include a single, main near circular open cut of diameter ~200m, depth between 50-80m. Production under Perilya ownership from 2008-2009 was ~316,000 tonne at 32%Zn, for total production from 1977-2009 of 663,000 tonne of zinc ore. Seasonal production for several years has been from stockpiled ore, which is railed to Port Pirie for shipment overseas.
Discovery Year
~ 1966
Commodities
Zinc, Lead
Ore Minerals
Hedyphane, Mimetite, Smithsonite, Willemite
Gangue Minerals
Clay mineral, Dolomite, Hematite
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