Gold mining has possibly been around since between 4700 and 4200BC which would indicate that humans were mining gold up to 7000 years ago.
A group of archaeologists from Germany and Georgia claim that the Sakdrisi site, located in the South of Georgia, dates back to the 3rd or 4th millennium BC making this the world’s oldest gold mine.
Gold rushes in remote regions caused an increase in migration of miners in the 19th century, such as the Victorian Gold Rush and the California Gold Rush of 1849. The discovery of gold ultimately led to the founding of South Africa.
As of 2015, China was the world’s largest gold producer, having mined 455 tonnes/year, second to Australia who mined 270 tonnes/year, with Russia following behind with 250 tonnes/year.
There are several different methods miners use to extract the gold –
The technique by which gold that has accumulated in a placer deposit is extracted. A placer deposit is composed of fairly loose material which makes tunnelling difficult, therefore extracting the gold usually requires the use of water or dredging.
This method has been largely replaced by modern mining methods however this method is still used by some smaller scale miners using suction dredges. Suction dredges are small machines that float on water, consisting of a sluice box which is supported by pontoons with a suction hose attached which is controlled by a min er working beneath the water.
A sluice box is a man-made channel with riffles set in the bottom, these are designed to create dead zones in the current to allow gold to drop out of suspension.
Wide shallow pans are filled with sand and gravel that may contain gold, the pan is then lowered into water and shaken which sorts the gold from the gravel and other material. The gold is much denser meaning it will settle to the bottom of the pan. This is the easiest and quickest technique for looking for gold but is not viable for extracting gold from large deposits.
Uses riffles in a high walled box to trap gold, using a similar technique to the sluice box however this uses less water than a sluice box.
Hard rock mining
This method extracts the gold encased in rocks instead of collecting gold fragments found in loose sediment, this method produces most of the worlds gold.
By-product gold mining
Large copper mines often contain a considerable amount of gold and other metals alongside the copper.