The sale includes the Hazard thermal coal mining complex and infrastructure, as well as approximately 38 million tons of thermal coal reserves in eastern Kentucky.

Arch divested $15.6 million of reclamation liabilities to Blackhawk and expects to be released from $43.8 million of reclamation surety bonding.

Arch has the potential to receive future royalty payments of up to $35 million in aggregate over the next five years, resulting from its retention of select coal reserves at Hazard.

Arch and its subsidiaries retain 12 major mining complexes, and more than 5 billion tons of thermal and coking coal reserves across the US.

Hazard's complex includes four active surface mines: East-Mac & Nellie, Rowdy Gap, Bearville and Thunder Ridge, as well as the Teton preparation plant and Kentucky River Loading facility.

In 2013, Hazard sold 1.7Mt of thermal coal and generated $4.8 million in earnings before interest, taxes, depreciation and amortisation, Arch said.