Wednesday, March 18, 2009

PRODUCTION OF GOLD



The top three gold producing countries in the world are South Africa, the United States and Australia in that order.

According to the U.S. Geological Survey, Nevada is the largest U.S. gold-producing state. Other top U.S. gold producing states are Alaska, California, Colorado, New Mexico and Utah.

For more statistical information about gold and silver production in the United States: http://www.nma.org/statistics/pub_gold_silver.asp

Most gold in the United States is produced at above ground surface (open pit) mines. While mining and production methods vary from location to location. The following is a generic description of how gold is mined and produced around the world at modern operations.

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. Production in 1970 accounted for 79% of the world supply, producing about 1,000 tonnes. However by 2007 production was just 272 tonnes. This sharp decline was due to the increasing difficulty of extraction, changing economic factors affecting the industry, and tightened safety auditing. In 2007 China (with 276 tonnes) overtook South Africa as the world's largest gold producer, the first time since 1905 that South Africa has not been the largest.

Other major producers are the United States, Australia, China, Russia and Peru. Mines in South Dakota and Nevada supply two-thirds of gold used in the United States. In South America, the controversial project Pascua Lama aims at exploitation of rich fields in the high mountains of Atacama Desert, at the border between Chile and Argentina. Today about one-quarter of the world gold output is estimated to originate from artisanal or small scale mining.

After initial production, gold is often subsequently refined industrially by the Wohlwill process or the Miller process. Other methods of assaying and purifying smaller amounts of gold include parting and inquartation as well as cuppelation, or refining methods based on the dissolution of gold in aqua regia.

The world's oceans hold a vast amount of gold, but in very low concentrations (perhaps 1–2 parts per 10 billion). A number of people have claimed to be able to economically recover gold from sea water, but so far they have all been either mistaken or crooks. Reverend Prescott Jernegan ran a gold-from-seawater swindle in America in the 1890s. A British fraudster ran the same scam in England in the early 1900s.

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