Alliance Resource Partners, L.P., a diversified natural resource company, produces and markets coal primarily to utilities and industrial users in the United States. The company operates through three segments: Illinois Basin, Appalachia, and Minerals. It produces a range of thermal and metallurgical coal with sulfur and heat contents. The company operates seven underground mining complexes in Illinois, Indiana, Kentucky, Maryland, and West Virginia. It also leases land and operates a coal loading terminal on the Ohio River at Mt. Vernon, Indiana; and buys and resells coal, as well as owns interests in various oil and gas mineral interests located within producing basins in the continental United States. In addition, the company offers various industrial and mining technology products and services, such as miner and equipment tracking systems, and proximity detection systems. As of December 31, 2019, it had approximately 1.69 billion tons of proven and probable coal reserves in Illinois, Indiana, Kentucky, Maryland, Pennsylvania, and West Virginia. Alliance Resource Management GP, LLC serves as the general partner of the company. The company was founded in 1971 and is headquartered in Tulsa, Oklahoma.