CSA Mine is a currently producing, high-grade, underground copper mine located in New South Wales. The mine is regarded as one of the highest-grade copper mines in Australia.

The project is fully owned by Metals Acquisition Limited (MAC).

CSA Mine has an annual production of 40,000 tonnes of copper, which is transported to the Port of Newcastle for export.

The current mine life of the project is estimated to be 15 years to 2036.

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CSA Mine location details

CSA Mine is located in western New South Wales, approximately 600km west-northwest of Sydney and 11km northwest of the town of Cobar.

With a depth of around 1.9km, the CSA mine is considered the second-deepest copper mine in Australia.

Ownership History

The CSA mine was initially discovered in 1871 and early mine development commenced in the 1900s.

Underground mining operations at CSA mine commenced in 1965 with Broken Hill South developing a new mechanised underground mining and processing operation. Subsequently, the project operated under different ownerships.

Glencore acquired the project in 1999 and the project began operating under Cobar Management Pty Limited (CMPL), a wholly owned Australian subsidiary of Glencore Operations Australia.

In June 2023, Metals Acquisition Limited (MAC) acquired the CSA copper mine from CMPL.

As agreed, MAC assumed ownership and full operational control of the mine, while Glencore will offtake 100% of the copper concentrate produced at CMPL.

Under the terms of the agreement, Glencore received $775m in cash and $100m in ordinary shares of MAC as consideration. The consideration also includes $75m deferred payment within 12 months; $150m contingent payment upon future copper prices; and 1.5% life of mine Net Smelter Return royalty on copper.

MAC also made the first shipment from the CSA mine from the port of Newcastle in June 2023. The shipment included approximately 2,300 tonnes of copper and 28,000 ounces of silver.

Geology and Mineralisation

The CSA deposit is located within the Cobar mineral field in the mineralised belt of Cobar Basin, which hosts copper, gold, and lead-zinc mineralisation.

At CSA mine, mineralisation occurs within the Silurian-age CSA Siltstone, a steeply dipping sequence of interbedded siltstones and sandstones.

The mineralisation is found in five known systems- Eastern, Western, QTS North, QTS Central, and QTS South.

Each system hosts multiple lenses, which are typically 5-30m wide with usually short strike lengths and down plunge extent of up to 1,000m.

Chalcopyrite is the dominant copper sulphide phase in all five systems. Silver is found at the property as acanthite.

CSA Mine Reserve Estimate

As of March 2022, CSA Mine had Measured and Indicated resources of 8.1Mt at 5.37% Cu for 435kt of contained copper, and 22g/t Ag for 5.71Moz of contained silver.

Inferred resources totalled 5.2Mt at 5.2% Cu for 272kt of contained copper, and 20g/t Ag for 3.30Moz of contained silver.

CSA provides an annual Mineral Reserve estimate, which is based on actual stope designs and after incorporating mining losses and dilution.

As of December 2022, Mineral Reserve estimate for the mine is 7.9 Mt (Proven + Probable) at 4.0% Cu and 16.1% Ag g/t.

Mining and Ore processing

The CSA mine employs mechanised long-hole open-stoping (LHOS) with cemented paste fill (CPF) as the mining method.

The project uses a modified Avoca stoping method in the narrower lenses.

With the mine now getting deeper, the mining efforts aim to maximise ore production. MAC aims to produce 1.2Mtpa of ore in future.

The project infrastructure includes a CSA processing plant with a conventional underground crush, surface grind, and flotation circuit. The grinding mills and the coarse ore bins which have been operating for a long time are now causing downtime problems.

The Semi Autogenous Grinding (SAG) mills in the grinding mills section are being upgraded to improve grinding circuit overall utilisation rate.

The annual production from the CSA mine is approximately 40,000 tonnes of copper per annum. After processing, the product is transported via rail to the Port of Newcastle for export to smelters in Asia.

Infrastructure and Accessibility

The site can be accessed via sealed highways from Sydney to Cobar. A sealed airstrip at Cobar operates commercial flights three times per week to and from Sydney.

CSA mine has access to a rail line that allows the transport of concentrate products to the Port of Newcastle.

The power required for mining operations is supplied to the site via a 132kV transmission line from Essential Energy’s western NSW network. The site also has access to a 22kV line from Cobar for limited supply during emergencies.

Majority of water for the mining operations is provided by the Cobar Water Board from a weir on the Bogan River at Nyngan via pumps and pipelines. Additional water is procured from tailings water recycling, surface water capture, and a bore field installed in 2019.

Usually, the project requires 3 megalitres per day (ML/day) in summer.

Key Contractors Involved

Cube Consulting was engaged to independently estimate the Mineral Resources of the copper mine.

In June 2022, ABB announced the development of an electric charging solution for CSA mine to enable the transition to electric vehicles.

ABB supplied its Heavy Vehicle Electric Charger technology (HVC-150C), a fast-charging solution, to deliver 150kW of DC power to fully charge battery electric loader in less than two hours.