3. Mining reserves

Although 39 mineral species are known in which selenium is the main constituent, and 40 species for tellurium, and these elements are often found associated with sulfides, there are no deposits of selenium and/or tellurium. In copper, nickel, gold, silver and lead deposits, selenium and tellurium recovery is incidental. Table 2 shows the selenium and tellurium reserves associated with economic-grade copper deposits. According to Brown [8] , they average 0.215 kg Se and 0.065 kg Te per tonne of recoverable copper. The main reserve holders are Chile and the United States (over 40% of Se reserves and over 30% of Te reserves).