Capstone Copper Ratifies Union Deals at Mantos Blancos Mine

Capstone Copper has locked down labour peace at its Mantos Blancos mine in Chile. The Vancouver-based miner said it ratified three-year collective bargaining agreements with both unions at the site, settling within the legal timeframe set by Chilean law.

Mantos Blancos employs about 1,106 people directly, with 92% of them drawn from local communities in the Antofagasta region. Adding contractors, the total workforce at the copper-silver operation comes to roughly 2,928 people. The new contracts run through 2029, giving Capstone cost predictability on the largest line item at one of its core operations.

Capstone runs four producing mines. Pinto Valley sits in Arizona. Cozamin is in Mexico. Mantos Blancos is in Chile. The company also operates the Mantoverde copper-gold mine in Chile and owns the fully permitted Santo Domingo development project. Mantos Blancos is a mid-tier contributor to Capstone's production profile, and the agreement removes a potential disruption that the company had flagged in its risk disclosures.

For copper traders, the deal knocks out one supply-side variable from the Chilean market. Labour stoppages at Chilean mines have historically triggered production halts and price spikes. By locking in work rules and wage costs for three years, Capstone removes that risk from its 2026 output and cost guidance.