This made Hydro a significant player in bauxite mining and alumina refining. Iron, bauxite, manganese, clays, limestone, and silica are mined. Salem district has one of the largest magnesite, bauxite and iron ore deposits in India. Bauxite and alumina are currently the only major exports. Limestone, bauxite and iron ore are found in the Eastern Ghats hill ranges. It is also rich in diamonds, manganese ore, bauxite, and oil. Industrial minerals and exports from South Ghana are gold, silver, timber, diamonds, bauxite, and manganese. Limestone, dolomite and bauxite are abundant. Calcium aluminate cements are hydraulic cements made primarily from limestone and bauxite. Significant industries include tourism, cattle grazing, agriculture and mining of both sand and bauxite. These compounds together are the major components of the aluminium ore bauxite. Negotiations for reactivation of rutile and bauxite mining are in progress. Almost all metallic aluminium is produced from the ore bauxite (AlO(OH)). There are also reservoirs of low-grade coal, chalk, bauxite, and zircon. The state is rich in mineral deposits, especially gold, diamonds, cassiterite, bauxite, marble, and copper.