Mining and Quarrying   Annual coal production averages between 4,000,000 and 4,500,000 tons. Copper production is about 3,900 tons. Quarrying of marble exceeds 1,100,000 tons and of dolomite 55,000 tons. Annual production of crude petroleum is about 88,000 tons and that natural gas about 1,200,000. Salt production is located mainly on the southwestern coast.