A federal judge says the U.S. Interior Department must re-analyze a 117-million ton expansion of a Montana coal mine after environmentalists sued over the project's potential climate change impacts.

U.S. District Judge Susan Watters says federal officials have nine months to re-examine the proposal for the Spring Creek mine near the Wyoming border.

That follows similar rulings affecting two coal mines in Colorado, and after the industry has been battered by bankruptcies and falling domestic and international demand for coal.

Owner Cloud Peak Energy has warned a permit cancellation would trigger layoffs for most of Spring Creek's 275 workers. The expansion would keep mining going at least through 2022.

Watters also said in Thursday's ruling that the government violated public notice provisions in its handling of Cloud Peak's mining application.