More than 80 miners could be laid off from a central Montana coal mine in coming months after environmentalists successfully sued to halt its expansion, according to mine owner Signal Peak Energy.

U.S. District Judge Donald Molloy last month blocked the company’s plans to mine a 176-million-ton federal coal reserve adjacent to the mine. Molloy criticized government officials for downplaying the mine’s potential climate change impacts and inflating its economic benefits.

Signal Peak President Bradley Hanson said in a court affidavit filed Monday that about 30 employees at the Bull Mountain mine north of Billings could run out of work by the end of October and another 50 workers could run out of work by next March.

The layoffs could be avoided if Molloy allows preliminary work within the federal leases to continue while the case is pending, Hanson said in the affidavit. That work would remove about 170,000 tons of coal, which Hanson said could be stockpiled pending completion of an additional analysis of the expansion that Molloy had ordered.

“We believe that we can avoid the impacts that prompted the court’s order and, at the same time, preserve the jobs and the economic value of this mine,” Hanson said.

If the case drags on until 2019, Hanson said as many as 160 of the mine’s approximately 250 workers could face layoffs.

In his Aug. 14 order, Molloy said the Interior Department’s Office of Surface Mining must consider the environmental effects of shipping the fuel to customers in Asia and the greenhouse gases and other pollutants emitted when the fuel is burned to generate electricity.

Federal mining officials had claimed there would be no additional environmental impacts from burning more coal from Bull Mountain because its customers would simply go somewhere else if the expansion were not approved.

Courts in Colorado and Montana previously have issued similar rulings about greenhouse gas emissions from mine expansions. In those cases, the expansions ultimately were allowed to proceed following further environmental reviews.

Bull Mountain is a major employer in central Montana. As much as 95 percent of its coal has been exported in past years, to South Korea, Japan and the Netherlands, according to court filings in the case.