Arch Mineral had its origins in 1969, when it was formed as a partnership between Ashland Oil (now Ashland Inc.) and the H.L.Hunt family of Dallas, Texas; Ashland Coal was formed in 1975 as a wholly owned subsidiary of Ashland Oil.
Компания Arch Coal была образована в 1997 году путём слияния Arch Mineral (основана в 1969 году) и Ashland Coal (основана в 1975 году).