Capstone Copper faces temporary output setback at Mantoverde Mine in Chile

Despite the temporary disruption, Capstone Copper remains on track with its long-term growth strategy, positioning Mantoverde as a cornerstone asset within its expanding global portfolio.

Capstone Copper (TSX: CS; ASX: CSC) has announced a temporary production setback at its Mantoverde sulphide operation in Chile, following the failure of both ball mill drive motors within a week.

In a press release issued Monday, the Vancouver-based copper miner said the first motor failure occurred on August 24, and the unit was replaced with a spare. However, the lack of additional spares left the operation vulnerable when a second motor broke down six days later.

As a result, the Mantoverde processing plant will operate at 50% capacity by bypassing the affected mill, a mode the company has previously implemented. Management added that this unplanned downtime provides an opportunity to bring forward scheduled plant maintenance originally set for late September.

Capstone estimates the repairs will take about four weeks, with a production impact of 3,000–4,000 tonnes of copper concentrate. The company has also launched an investigation into the root cause of the failures.

Capstone’s broader copper portfolio

Beyond Mantoverde, Capstone Copper operates several other key assets:

• Mantos Blancos copper-silver mine in Chile’s Antofagasta region.
• Pinto Valley copper mine in Arizona, USA.
• Cozamin copper-silver mine in Zacatecas, Mexico.

In July 2024, Capstone secured environmental approval for its $150 million Mantoverde Optimized (MV-O) project from regulators in Chile’s Atacama region. This approval extends Mantoverde’s mine life from 19 to 25 years and represents a crucial step in Capstone’s plan to establish a major copper-cobalt district in northern Chile.

Once the MV-O expansion is operational, annual copper equivalent output is expected to increase to 125,000–135,000 tonnes, up from the current 97,000–112,000 tonnes.

Recent milestones at Mantoverde

Capstone achieved first saleable copper concentrate at Mantoverde in June 2024, with commercial production beginning three months later. By January 2025, the plant had already exceeded nameplate capacity, reaching an average throughput of 33,409 tonnes per day.