BHP Group has suspended all operational activities at Chile’s Escondida copper mine, the world’s largest, after a worker died during maintenance on September 24. Union officials said the incident involved a front-end loader.

The shutdown comes as BHP faces the prospect of a strike at the mine. The supervisors’ union is set to vote on a new pay offer between September 28 and 30, and union leaders are urging members to strike if they reject it.

BHP shares fell in the prior session. The company has not said when operations might resume.