709 workers strike at Chile's Centinela as company maintains copper output forecast
Key Facts
Two unions representing 709 workers at Antofagasta's Centinela copper mine in Chile began a strike on 7 October 2026, according to a company statement that kept its production forecast unchanged. Members of the striking Minera Esperanza and Distrito Centinela unions account for 22% of the mine's direct workforce. Centinela said in its statement that "expected production remains unchanged", despite the operational impact of the labour dispute. The unions, however, warned that copper production would start to be affected within about two weeks if the strike continued, according to Bloomberg. The unions said feed to processing plants had continued, while much of the material movement and mine development work had stopped.
The strike followed collective bargaining that began on 1 August and included mediation by the Labour Directorate before the dispute escalated into a work stoppage. According to Centinela, the two unions rejected the company's final offer during that negotiating process. The offer included a real increase in base pay of 2%, alongside proposed payments and financial benefits to conclude negotiations. These included a net end-of-negotiation bonus of 22.5 million Chilean pesos, according to details of the offer released by the company. It also included a soft loan with a net value of 3.5 million Chilean pesos. Explaining differences in pay and benefits, the company said they reflected the evolution of collective agreements negotiated by the unions at "different times and in different forms".
The dispute affects a mine that produced 240,400 tonnes of copper in 2025, according to Antofagasta's annual report, an annual increase of 7%. Copper production in concentrates rose, partially offsetting a decline in cathode output during the year. At group level, annual copper production totalled 653,700 tonnes, down 2%, according to the annual report summary. Contributions from Centinela Cathodes and Los Pelambres to group production declined during that period. Centinela's forecast for the current year in the annual report was 195–215 thousand tonnes, with concentrate production expected to moderate as ore grades returned to historical levels.
Group production had also fallen in the first half of 2026, according to Antofagasta's half-year results. Output during that period was about 285,000 tonnes of copper, down 9% from a year earlier. The company attributed the decline mainly to lower production at Los Pelambres and Centinela. In its half-year results, the group set its 2026 copper production forecast at 625,000–655,000 tonnes. That forecast followed the impact of exceptional weather on operations at Los Pelambres, while Centinela entered the labour dispute with its published operating estimates unchanged.
Centinela also hosts the second concentrator project, whose development Antofagasta approved at an estimated cost of about $4.4 billion. The expansion was designed to add average annual copper production of 144,000 tonnes, according to the company's announcement when it approved the project. That average covers an initial period of 10 years of production from the expansion. The development decision set 2027 as the expected date for first production from the project. The planned addition is at the same mine where unions said much of the material movement and development work had stopped during the strike, while feed to processing plants continued.
In the copper market, benchmark London futures rose during Wednesday's session, according to a Bloomberg report published on 8 October 2026. They settled up 0.4% at $14,475.50 a metric tonne. The metal rose as the strike took effect at one of the Chilean group's mines and the company and unions remained at odds over its impact on production. Antofagasta had set a date in its shareholder calendar for its next operational disclosure after the dispute began. According to that calendar, the third-quarter production report was scheduled for release on 15 October 2026.