For millennia, gold has had a special allure. Today, gold remains one of the world's most precious metals. It's widely used in jewelry manufacture and has various industrial uses as well. Additionally, many countries rely on maintaining vast gold reserves to back the value of their currency. Gold miners use a number of processes to extract the metal from the ground.
Old-fashioned methods used for gold-mining involved simple tools and much manual labor. Gold miners used "pans" with which they would search riverbeds for gold nuggets. More effective tools developed later included the "rocker," a device that resembled a baby's rocker and could sift gold pieces from gravel. Miners also relied on pickaxes and shovels to break through rock and dig into the earth where gold was suspected to be present.
Open Pit Mining
In open pit mining, gold ore is crushed in the pit and removed via conveyor to a gold mill. There it is processed, which involves smelting it down and separating pure gold from impurities, which are retained if they have any value.
Highbanking is a low-level method of gold extraction that uses a machine called a highbanker. The highbanker is equipped with a pump that propels water through a hopper box. Large quantities of gravel are fed into the machine and propelled through a filter that separates the gold. Highbankers recirculate water to make them more efficient in arid conditions.
Placer mining is a method that uses dredging and hydraulics to break the gold from the rock. Some placer mining operations are huge and can displace millions of tons of rock and water, which are discarded. This is among the most efficient mining methods.