Capstone Copper (ASX:CSC) said Union No. 2, one of four unions at its Mantoverde copper-gold mine in Chile, has notified the company it will begin strike action effective Jan. 2, affecting about 50% of Mantoverde employees, or roughly 22% of the site's total workforce.
The Vancouver-based miner said it had negotiated in good faith toward a new collective bargaining agreement and will now gradually scale back certain activities while maintaining safe operations, with production expected to continue at up to 30% of normal levels during the strike.
Capstone said it remains open to dialogue and will continue to follow legal procedures, noting that the three other unions at Mantoverde successfully reached new three-year agreements in 2025.
The company added that Mantoverde employs about 1,270 workers, including around 550 from local Atacama communities, and forms part of Capstone's broader Americas-focused copper portfolio.
At the time of reporting, Capstone Copper’s share price was $13.78.