Kentucky, US-based ADDCAR is involved in the manufacturing, servicing and operating of highwall mining equipment.

As part of the agreement, UGM will acquire all licenses, patents and technology related to the ADDCAR highwall mining system and the manufacturing facility, situated in Ashland.

The acquisition also includes all the existing contract mining and equipment lease agreements.

Arch Coal president and CEO John Eaves said that the divestiture is consistent with previously announced and ongoing efforts to monetize non-core assets.

"With this sale, we are continuing to sharpen our focus on our core competencies – mining and marketing coal," Eaves added.

"We wish UGM success as it expands its mining expertise and reach, and we thank the employees of ADDCAR for their dedication and professionalism."

Since the International Coal Group (ICG) acquisition in 2011, ADDCAR has been a wholly-owned subsidiary of Arch Coal.