NYE, Mont. (AP) – Two workers at the only palladium and platinum mining operation in the United States have died in an underground crash at a mine in Montana, company officials said.

The employees were in a utility vehicle called a side-by-side that crashed into an underground locomotive on Wednesday afternoon, said Heather McDowell, vice president of South African company Sibanye-Stillwater, owner of Stillwater Mining Co.

The cause of the mine accident near the community of Nye, north of Yellowstone National Park, is under investigation. Mine officials said they were working with safety regulators.

The identity of the workers has not been made public.

In a statement, company officials said: “We attach paramount importance to safety. Our thoughts and prayers are with all those affected by this tragic event.”

Stillwater Mining Co. has 2,335 employees and contractors, according to its website. Just over 1,200 of them work at the Nye mine, McDowell said.

Its other palladium and platinum mine is near the small town of Big Timber in Montana, and the company has a refining complex in nearby Columbus.

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