With the Montana Land Board unanimous approval, the Signal Peak will expand the mine’s life to nine additional years, The Billings Gazette reports.

The Bull Mountain mine, which employs about 325 people, is expected to generate $127.2m in revenue from state taxes and royalties from state coal land involved in the expansion.

Over the next nine years, the expansion would assure workforce of about 200 to 250 at the Bull Mountain mine.

Comprising approximately 431 million tons of recoverable reserves below ground and 109 million tons above, the mine has produced 8.7 million short tons of coal last year.