Arch Coal sold its ADDCAR highwall mining machine manufacturing division to UGM Holdings for $21 million. The transaction includes all licenses, patents and technology related to ADDCAR’s highwall mining system and its manufacturing facility in Ashland, Ky.; it also includes existing lease agreements. ADDCAR became an Arch subsidiary when the company acquired International Coal Group in 2011. Australian-based UGM Holdings is a privately held, diversified professional services firm supporting mining and related industries.