Why is mercury contamination associated with gold mining?
Undercurrent in use, circa 1860, Siskyou County, California. Gravel and cobbles that entered the sluice at high velocity caused the mercury to flour, or break into tiny particles. Flouring was aggravated by agitation, exposure of mercury to air, and other chemical reactions.
Why is artisanal gold mining bad?
Artisanal gold mining is actually among the leading causes of global mercury pollution, ahead of coal-fired power plants. When mercury enters the atmosphere or reaches rivers, lakes, and oceans, it can travel across great distances.
Can you get mercury poisoning from gold?
Artisanal and small-scale gold mining is a vital source of income, but it is also very dangerous because miners use toxic mercury to separate the gold from the ore. Mercury is a shiny liquid metal that attacks the nervous system. Exposure can result in life-long disability, and is particularly harmful to children.
Does mining increase mercury levels?
However, it is a significant source of environmental mercury contamination which affects human health. Amalgamation and amalgam smelting, two significant steps in the artisanal small-scale mining operations generate lots of mercury vapors, leading to chronic exposure among miners.
How is mercury extracted using gold?
In many countries, elemental mercury is used in artisanal and small-scale gold mining. Mercury is mixed with gold-containing materials, forming a mercury-gold amalgam which is then heated, vaporizing the mercury to obtain the gold.
Is mercury a byproduct of gold mining?
Since at least Roman times, mercury has been used for amalgamation with gold. The Romans used mercury from cinnabar — the most important ore of mercury — from Almadén, Spain, home to the world’s oldest producing mercury mine. Mercury also is recovered as a byproduct of copper, gold, lead-zinc, or silver processing.
Is mercury still used in gold mining?
Most large-scale and regulated gold mining companies do not use mercury in their mining operations. However, Small-scale and illegal gold mining operations will sometimes use mercury to separate the gold from other materials.
What happens when mercury reacts with gold?
Mercury and gold settle and combine together to form an amalgam. Gold is then extracted by vaporizing the mercury. Although mercury is a naturally occurring element, it is highly toxic to humans, animals, and the environment when not handled properly.
How is mercury used in gold mining?
In mines, mercury is used to recover minute pieces of gold that is mixed in soil and sediments. Mercury and gold settle and combine together to form an amalgam. Gold is then extracted by vaporizing the mercury.
How much mercury is used in gold mining?
Producing a pound of gold requires about 6 pounds of mercury. Given that at least 50% of the mercury used in these operations is lost to the environment, we estimate that artisanal gold mining in Peru alone releases nearly 50,000 pounds of mercury annually.