Supervisors at BHP's Escondida copper mine in Chile, the world's largest, voted to reject the company's latest contract offer. Approximately 95% authorized a strike. The union represents more than 1,000 supervisors.
The union said the proposal did not meaningfully improve on the current contract and objected to new multitasking requirements.
The vote triggers a mandatory, government-led mediation period of five days. The period can be extended by another five days if both parties agree.
Production has not been affected. If the parties fail to reach an agreement during mediation, a legal strike could follow, creating uncertainty for global copper supply.