BILLINGS, Mont. (AP) — Montana regulators have reached a deal allowing the state to enforce environmental laws at a large coal mine bought last year by a Navajo-owned company.

Company executives and state officials had been at odds for months over demands that the Navajo Transitional Energy Company waive its immunity as a tribal entity from future lawsuits.

Thursday's agreement came a day before a temporary waiver for the Spring Creek mine was set to expire.

The 275-worker strip mine is one of the largest in the U.S.

Litigation is a key tool to enforce many environmental laws. But tribal entities can't normally be sued in state court.

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