The Black Thunder Coal Mine, Arch’s largest mine. Credit: morrison-knudsen

One of the nation’s largest coal companies, Arch Coal, filed for bankruptcy Monday, making it the second company with large Western mines to seek Chapter 11 restructuring in recent months.

The St. Louis-based company announced that it expects to continue to operate its mines and pay its 4,600 employees while it seeks a bankruptcy court’s approval for its debt restructuring.  Arch said its lenders had agreed to reduce its debt by more than $4.5 billion, but that deal would have to be approved by the court.

Responding to its employees’ and retirees’ fears, Arch said it does not anticipate major layoffs or disruptions to its pensions due to the bankruptcy. But it conceded that market conditions may impact staffing. The company operates two surface mines in Wyoming’s Powder River Basin as well as the underground West Elk mine in Somerset, Colorado. It has proposed opening a surface mine in southeastern Montana, the Otter Creek project. […]