Cobre Limited announced on September 9 that its Sierra Atacama operation in Chile has signed ore-purchase agreements with two third-party copper oxide miners in the Antofagasta region, with deliveries expected to ramp up from Q4 2026. The agreements are expected to supply approximately 50,000–75,000 tonnes of oxide ore per month grading 1.0–1.5% total copper, adding around 300 tonnes per month of copper cathode production.
The additional production will be processed through Sierra Atacama’s existing SX-EW plant, which has installed copper cathode capacity of approximately 20,000 tonnes per year and is currently operating below nameplate capacity. As the purchased ore does not require Cobre to incur its own mining and development costs, the company said incremental costs will primarily comprise the ore purchase price and variable processing costs, including acid, power and reagents. Higher throughput is also expected to spread the plant’s fixed costs over a larger production base.
The approximately 300 tonnes per month of additional cathode will be incremental to Cobre’s previously announced production targets, which remain unchanged. The company is continuing to stabilise underground production while preparing to transition toward a larger open-pit operation from 2027. Cobre said negotiations with additional regional ore suppliers are also underway, potentially providing further feed for the under-utilised SX-EW facility.
The agreements represent a near-term increase in copper cathode supply from Sierra Atacama without requiring additional mining development or new processing capacity. At the initial expected rate, the third-party feed could contribute approximately 3,600 tonnes of additional cathode on an annualised basis. More importantly, it should raise utilisation of the existing SX-EW plant ahead of Cobre’s planned transition to expanded open-pit production in 2027. Further ore-supply agreements would provide additional upside to plant utilisation and cathode output.
