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Beskrivelse
Gold, a chemical element with the symbol Au, is a highly sought-after precious metal, having been used as money, in jewelry, in sculpture, and for ornamentation since the beginning of recorded history. The metal occurs as nuggets or grains in rocks, in veins and in alluvial deposits. Gold mining consists of the processes and techniques employed in the removal of gold from the ground. There are several techniques by which gold may be extracted from the Earth. Since the 1880s, South Africa has been the source for a large proportion of the world's gold supply, with about 50% of all gold ever produced having come from South Africa. Other major producers are the United States, Australia, China, Russia and Peru. The world's oceans also hold a vast amount of gold, but in very low concentrations. At current consumption rates, the supply of gold is believed to last 45 years. This book will present current research on gold mining including methodologies for discovering new deposits of gold as well as economic and environmental issues.