Capstone announces temporary production interruption at Mantoverde

[Ben Graham]

Capstone Copper (TSX: CS; ASX: CSC) has warned of a temporary output hit at its Mantoverde sulphide operation in Chile after both ball mill drive motors failed within a week, forcing the concentrator to run at roughly half capacity while repairs are made.

The company expects a four-week repair window and estimates a 3,000–4,000 tonne reduction in copper-in-concentrate during the period. It is investigating the root cause and is pulling forward maintenance originally slated for later in September to soften the impact.

Capstone said one of Mantoverde’s two ball mill motors failed on August 24, was replaced with a spare, and then the second motor failed on August 30, leaving no additional spare on site. The plant is configured to bypass the mill and continue at reduced rates, a mode the team has used before, the company noted.

Besides Mantoverde, the Vancouver-based company owns and operates the Pinto Valley copper mine in Arizona, USA; the Cozamin copper-silver mine in Zacatecas, Mexico; and the Mantos Blancos copper-silver mine in Chile’s Antofagasta region.

Back in July, the miner secured environmental approval from authorities in Chile’s Atacama region for its $150-million Mantoverde Optimized (MV-O) project.

The green light extended the mine’s life from 19 to 25 years and marked a key step in Capstone’s broader plans to create a major copper-cobalt district in northern Chile.

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

The Vancouver-based miner produced the first saleable copper concentrate at the site in June 2024, and kicked off commercial production in late September. In January this year, the plant exceeded nameplate capacity with an average throughput of 33,409 tonnes per day.