Alcoa Corp. engages in the bauxite mining, alumina refining, and aluminum smelting and casting. It operates through the Alumina and Aluminum segments. The Alumina segment consists of a refining system, including the mining of bauxite, which is then refined into alumina, a compound of aluminum and oxygen that is the raw material used by smelters to produce aluminum metal. The Aluminum segment is composed of smelting and cast