Minera Centinela Strike Vote Passes With 98.73% Backing in Chile
Business · Chile
Key Facts
- —What happened A Minera Centinela strike vote in northern Chile passed with 98.73% backing on 28 September 2026.
- —What the fight is about Members say they are paid less, and get fewer benefits, than people doing the same jobs in another union.
- —The catch A vote is not a walkout: Chilean law sets further steps, and nobody has reported any effect on output.
- —How much is at stake Centinela produced 240,400 tonnes of copper in 2025, about 4.4% of everything Chile mined that year.
- —What comes next Either side has four days from the vote to ask a labour inspector to mediate, which delays any stoppage.
Two unions at a large mine in northern Chile say their members earn less than colleagues doing identical work. The Minera Centinela strike vote passed almost unanimously, and the unions called a rally at the owner’s Santiago offices.
A Minera Centinela strike vote has passed in northern Chile, and the unions behind it called a rally in the capital. They said 98.73% of their members backed a walkout.
The count closed on Monday 28 September 2026, with every eligible member casting a ballot. They set the rally for midday Santiago time the following day, Tuesday 29 September 2026.
Their chosen address was the corporate building of Antofagasta Minerals in Las Condes, a business district of the Chilean capital. The mine itself lies far to the north, in the Atacama Desert.
The argument is about equal treatment, not safety
The two organisations are the Minera Esperanza union and the Distrito Centinela union. Together they represent about 730 workers, by their own count.
Their complaint is narrow and specific. They say their members receive lower pay and weaker benefits than colleagues who do identical jobs.
Those colleagues belong to a different union at the same operation. The unions called that systematic discrimination in a public statement carried by La Tercera.
They say the company has so far declined to put a remedy on the table. No figure has been published for the size of the gap the unions describe.
Nor has any safety complaint, contractor dispute or objection to the mine’s expansion been part of this round.
How the talks got here
The two unions handed the company a joint draft contract on 14 August 2026, seeking terms for three years. Bargaining jointly is new for them at this mine.
Antofagasta Minerals presented what Chilean law calls a final offer on 23 September 2026. The union leaderships urged members to reject it and opened voting three days later.
Reuters quoted the unions the day the offer landed. “The latest offer received today does not even resolve the discrimination, as long-standing disparities remain,” they said in a statement.
Antofagasta Minerals does not comment on its collective bargaining, Reuters reported on 28 September 2026. The company has made no public statement on the vote.
A vote is not yet a stoppage
Chile’s Labour Code is precise about what follows. Article 350 says an approved strike takes effect at the start of the shift on the fifth day after the vote.
That clock can be stopped. Article 351 lets either side, within four days of the vote, ask the competent labour inspector for what it calls obligatory mediation.
The Labour Directorate, the state body that enforces employment law, then has five working days to try to bridge the gap. Both sides may agree to extend that by five more.
The strike is suspended for as long as the mediation runs, the Directorate says. Neither the unions nor the company has been reported as having asked for it.
What would settle this is an offer that closes the pay gap the unions describe. They have also asked for a mechanism to stop the difference reappearing later.
Why a rally in Santiago reaches further than Chile
Centinela produced 240,400 tonnes of copper in 2025, its owner reported in the Antofagasta plc annual report. That was 7% more than the year before.
Chile mined 5,415,200 tonnes in the same year, according to Cochilco, the state copper commission, in figures published on 10 February 2026. Centinela therefore accounts for about 4.4% of the national total.
Chile supplied 23.6% of world copper production in 2024, Cochilco said when it published its ten-year outlook in January 2025. Copper runs through household wiring, electric motors and power grids, so an interruption in the Atacama moves prices far away.
Escondida, the biggest single mine in the country, produced 1,345,100 tonnes in 2025 on the same Cochilco figures. Centinela is important without being decisive on its own.
Centinela is the second-largest producer in its group, behind Los Pelambres at 295,300 tonnes last year. Antofagasta plc owns 70% of the mine and runs it, with Japan’s Marubeni Corporation holding 30%.
An expansion is being built alongside the dispute
The company is spending heavily at the site. Capital expenditure at Centinela reached US$2,478.1 million in 2025, most of it on a second concentrator plant.
That project is designed to add about 144,000 tonnes of copper a year, plus gold and molybdenum. It was more than half complete at the end of 2025, with construction due to finish in 2027.
Ramp-up is due to start late in 2027 and the project to be complete in late 2028, the same report says. Guidance for Centinela this year is 195,000 to 215,000 tonnes, lower than 2025.
That forecast is the company’s own, published in its annual report. Output falls as ore grades and plant work shift.
Antofagasta’s mining division concluded four collective agreements at three operations in 2025, and four more expire this year. In May 2026 a separate supervisors’ union at Centinela approved a strike that never began.
That union backed a walkout with 77.21% of 702 votes, Diario Financiero reported on 13 May 2026. The company then asked for mediation, and the stoppage due the next morning was suspended.
For readers outside Chile, the question is whether mediation opens before the strike clock runs out. Both sides still have days in which to reach terms.
More: Chile coverage, every day from The Rio Times.
Frequently Asked Questions
What are the two unions asking for?
They want their members paid the same as workers who do identical jobs at Centinela but belong to another union. The unions say the difference covers both wages and benefits, and they have asked for a mechanism that prevents it returning in future contracts. The claim was the central point of the joint draft contract they presented on 14 August 2026. No published figure sets out how large the difference is.
Has production at the mine stopped?
No. The Minera Centinela strike vote of 28 September 2026 authorises a walkout; it does not start one. Under article 350 of Chile’s Labour Code, an approved strike becomes effective at the start of the shift on the fifth day after the vote, and that date moves if either side asks a labour inspector to mediate. No source has reported any effect on output at Centinela.
What has Antofagasta Minerals said?
Reuters reported on 28 September 2026 that Antofagasta Minerals does not comment on its collective bargaining negotiations. The company has issued no public statement on the strike vote or on the demonstration called outside its Santiago offices. The unions say they tried to take the matter directly to senior executives without success, and have appealed to the controlling Luksic family.
How important is Centinela to world supply?
It produced 240,400 tonnes of copper in 2025, about 4.4% of Chile’s 5,415,200 tonnes that year, according to the company and to Cochilco, the state copper commission. Chile supplied 23.6% of world copper production in 2024 on Cochilco’s numbers. Centinela is the second-largest mine in the Antofagasta plc group, after Los Pelambres.
Sources: Diario Financiero on the Santiago demonstration, Diario Financiero on the 98.73% vote, CNN Chile on the time and place of the rally, La Tercera on the unions’ statement and the ownership split, Reuters on the rejected offer and the company’s silence, Reuters on the final offer and the “dead end”, Redimin on the bargaining timetable and the legal steps, Antofagasta plc Annual Report 2025 on Centinela’s output and expansion, Chile’s Labour Directorate on mediation deadlines, Labour Directorate ruling quoting article 350 of the Labour Code, Diario Financiero on Cochilco’s 2025 national production data, Cochilco on Chile’s share of world output, Diario Financiero on the supervisors’ strike vote of 13 May 2026, BioBioChile on the company’s mediation request of 18 May 2026
In depth
Read More from The Rio Times