World mine production of copper was 15.8 million metric tonnes (Mt) in 2009; world reserves are estimated to be 540Mt, 34 years at 2009 rate of production. Twelve countries produced 86% of world production (link). Major sources of copper are found in disseminated form in magmatic rocks near continental plate junctions - principally along the west of the Americas and in central Asia (link). These are porphyry copper orebodies, of very low grade (typically 0.5% Cu or less); these ores are sulphides - the copper bearing minerals are mainly chalcopyrites and bornites.