The Montana Land Board unanimously approved the 7,160-acre expansion of Signal Peak's coal mine on Tuesday, a move adding nine years to the mine's life.
The expansion doubles the current size of the state's only underground coal mine, owned by Ohio-based Signal Peak Energy. Calls to Signal Peak Energy were not returned.
Formerly known as and permitted as the Bull Mountain Mine, the operation employs roughly 325 people between Roundup and Billings. The number of jobs wasn't lost on Land Board member Attorney General Tim Fox.
"Those 325 people who work at Bull Mountain combined make about $40 million a year," Fox said. "That's money that is spent in local stores and is important to the economy."
For the state, the mine expansion means $127.2 million in revenue from state taxes and royalties from state coal land included in the expansion. Montana's Common School Trust will receive $11.7 million. Shared federal royalties account for $14 million. Additional tax revenues are estimated to be $98 million.
Montana's coal share included in the expansion totals about 640 acres.
The board is composed of Fox, Gov. Steve Bullock, Secretary of State Linda McCullough, State Auditor Monica Lindeen and State Superintendent of Public Instruction Denise Juneau.
The state Department of Environmental Quality signed off on the mine expansion last October. The Bureau of Land Management approved the leasing of involved federal coal acres in 2012.
Over the long term, the expansion would assure Bull Mountain's workforce included 200 to 250 workers over the next nine years.
The mine has roughly 431 million tons of recoverable reserves below ground and 109 million tons above. Last year, the mine produced 8.7 million short tons of coal.
The mine, according to the company website, is capable of loading five to seven 120-car trains daily.
Last fall, community members raised concerns that mine expansion could impact area water and wildlife. State agencies concluded the impacts were insignificant.