Hundreds of workers at Capstone Copper’s Mantoverde mine in Chile began a legal strike on Friday, January 2, 2026, after mediated talks failed. Capstone disclosed the labour action the previous day and said the walkout involves Union No. 2, which represents about half of Mantoverde’s direct employees and 22 per cent of the site’s total workforce.
Talks ended without a deal on January 1, 2026, local time. “During the strike, Capstone expects to continue operations at Mantoverde at a level of up to 30% of normal production,” Capstone Copper said.
Output reduced to contingency levels
Union No. 2 stated the strike began at 8 a.m. local time and followed an extended bargaining process under Chilean law. The union has framed the stoppage as a response to unmet demands in the final round of talks.
“There was no agreement,” Eduardo Claveria said. Capstone said it will reduce activities in a safe manner and remains open to further meetings under the established procedures. The miner also noted it reached three-year agreements with Mantoverde’s other three unions in 2025, which remain in place.
Mantoverde is a copper and gold operation in the Atacama region, a mature mining district with established transport and power links. Capstone holds a 70 per cent interest in the asset, while Mitsubishi Materials owns 30 per cent, and the partners have been investing to stabilise output and costs. The mine’s expected 2025 production range is 29,000 to 32,000 tonnes of copper, offering a sense of scale for any prolonged disruption.
Chile remains the world’s largest copper producer, and labour actions at large sites often draw close attention from smelters and traders. Capstone has said it intends to keep authorities informed and maintain legal compliance throughout the work stoppage.
Near‑term implications for operations
Contingency staffing and minimum services are in place at Mantoverde while normal operations are curtailed. The company’s guidance during the stoppage points to materially lower throughput, with production capped at up to 30 per cent of usual levels. That level reduces near‑term concentrate and cathode volumes and may shift shipment schedules if the stoppage endures.
Ownership structure and joint‑venture governance remain unchanged, and Mitsubishi Materials’ interest does not alter the strike’s legal framework, which follows Chile’s regulated bargaining process. According to a Reuters summary, Capstone owns 70 per cent of Mantoverde and Mitsubishi Materials owns 30 per cent, and the company has indicated operations can continue at reduced rates during the strike, pending a negotiated resolution of the dispute between management and Union No. 2 at the mine in northern Chile, where miners began striking after talks between the main union and the company broke down late on Thursday.