Every stage of the mining process, including the ore extraction, generation of solid waste and ore refining and processing, creates air pollution that has environmental and public health impacts.
According to the US Toxics Release Inventory, the metal mining industry in the United States contributed the following, in 2010:
* 92% of industrial mercury emissions
* 94% of industrial arsenic emissions
* 73% of known Carcinogenic waste
Globally, metal mining is one of the biggest sources of air pollution.
To extract metal, ore is placed in a smelter, a type of furnace. The ore is subjected to very high temperatures in order to melt the metal and release it from other materials in the ore. While smelting technology has improved considerably over the past half century, they still release a great deal of toxins, in particular:
Smelters also release tons of greenhouse gases into the atmosphere. Aluminum smelters, for example, release two tons of carbon dioxide and 1.4 kilos of perfluorocarbons (PFCs) for every ton of aluminum produced. PFCs have up to 9,200 times the heat-trapping potential of carbon and will linger in the atmosphere for tens of thousands of years.
These toxins are harmful to workers and local communities. Exposure to mercury, for example, can result in illnesses ranging from impaired vision and muscle weakness to permanent kidney and nerve damage, depending on the level of exposure. Arsenic is a carcinogen. And high zinc exposure can lead to conditions such as anemia and metal fume fever. See below for more information on the environmental and health impacts of toxins generated and released during gold mining.