ACNR (together with its affiliates and subsidiaries) is the largest privately owned coal company in the United States and is headquartered in St. Clairsville, Ohio. ACNR will produce approximately 35 million tons of high-quality bituminous coal annually, and such operations include 9 active mines across the Northern and Southern Appalachia Basins (located in Ohio, West Virginia, and Alabama), the Illinois Basin (located in western Kentucky), and the Uintah Basin (located in Utah).

ACNR was created as a result o Murray Energy's chapter 11 bankruptcy filing where Murray sold nearly all its assets to ACNR.