Workers at Antofagasta's Centinela copper mine in Chile voted 98.73% in favour of a strike after rejecting the company's contract offer. The threat kept copper firm near $14,450 a tonne on a day when most metals fell.
At a glance
- Two unions at Centinela rejected Antofagasta Minerals' contract offer and backed a strike by 98.73%.
- A strike cannot start until a mandatory five-day government mediation ends, and that can be extended by five more days.
- Centinela produced 240,400 tonnes of copper in 2025.
Background
Chile is the world's largest copper producer, and a strike at one of its big mines can take thousands of tonnes off the market in weeks. Antofagasta Minerals, part of London-listed Antofagasta plc, runs Centinela in the Atacama desert of northern Chile. Chilean labour law requires a government-led mediation period before workers who vote to strike can walk out.
What happened
Workers from two unions at Centinela, the Minera Esperanza and Distrito Centinela unions, voted on Monday to reject Antofagasta Minerals' collective contract offer. They backed strike action by 98.73%.
The unions say the company has refused to discuss giving workers the same benefits regardless of which union they belong to. Antofagasta Minerals said it does not comment on ongoing collective bargaining.
Why the market is watching
Centinela produced 240,400 tonnes of copper in 2025, so a long stoppage would remove meaningful supply. It comes as Chile's supply is already under strain. BHP's Escondida, the world's largest copper mine, suspended mining last week after a worker died, and a strike there is also possible.
That supply risk kept copper firm. LME copper rose 0.2% to $14,447 a tonne on Tuesday as most other metals slipped. The metal is heading for a third straight monthly gain.
Stock levels tell a mixed story. LME warehouse stocks fell 875 tonnes to 251,350 tonnes, but only about half of that is actually available to buyers. COMEX stocks in the US passed 700,000 tonnes for the first time. Chinese buyers have also largely finished restocking ahead of the National Day holiday, which removes one source of support this week.
What comes next
No strike has started yet. The company and unions must first go through a five-day mediation led by the government, which can be extended by five days if both sides agree. The talks give both sides a last chance to settle before any output is lost.
For Indian buyers, MCX copper follows the LME, so a walkout at Centinela would likely feed into rupee prices. Makers of cables, motors and air conditioners are the most exposed.
Our read
Outlook: bullish. A strike at Centinela on top of Escondida's problems would tighten Chilean supply and support prices. A deal during mediation would remove most of that premium quickly.
What to watch
- The outcome of the five-day government mediation between Antofagasta Minerals and the two unions.
- Whether Escondida's operations and labour talks return to normal.
- LME inventories, which fell 875 tonnes to 251,350 tonnes.
For information only, not investment advice.
Copper price in India
metalscost.com India reference price as of 2026-10-03.
Detailed analysis
Timeline
- 2026-09-23: Unions at Centinela call a strike vote after contract talks reach an impasse.
- 2026-09-28: The two unions reject Antofagasta Minerals' offer and vote 98.73% to strike.
- 2026-09-29: LME copper rises 0.2% to $14,447 a tonne as supply worries grow.
Inventory Drivers
LME stocks fell 875 tonnes to 251,350 tonnes, while COMEX stocks passed 700,000 tonnes for the first time.
Mining Production
A strike at Centinela would put part of its 240,400 tonnes a year of output at risk.
What could lift prices
- Labour trouble at both Centinela and Escondida raises the risk of lost Chilean output.
- Copper is heading for a third straight monthly gain, showing steady buying interest.
What could weigh on prices
- A settlement during mediation would remove the strike risk before any output is lost.
- Chinese restocking before the National Day holiday is largely done, which may cool demand this week.
Country impact
| Country | Impact | Reason |
|---|---|---|
| Chile | High | A strike would cut output at one of the country's significant copper mines. |
| India | Low | MCX copper tracks the LME, so any supply-driven rise would reach Indian buyers. |
Industry impact
| Industry | Effect | Reason |
|---|---|---|
| Copper Mining | Negative | Antofagasta faces lost output if the dispute turns into a strike. |
| Wire and Cable Manufacturing | Negative | Tighter supply would raise the cost of their main raw material. |
Who gains, who loses
- Copper producers outside Chile: They would sell into a firmer market if Chilean supply is disrupted.
- Antofagasta: A strike would cut Centinela's output and revenue.
Other ways this could play out
- If mediation fails and workers walk out, copper could test new highs as Chilean supply tightens.
- If the sides agree on benefits during mediation, the strike premium in copper would fade.
Price risks
- A quick deal at Centinela would weaken the supply case.
- Softer Chinese demand after the holiday restocking could outweigh Chilean supply worries.
Technical view
Price is mixed relative to its 20-period and 50-period moving averages, showing no clear trend alignment.
Computed from metalscost.com's own stored price history.
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