Gold Mining and the Environment
Dirty gold mining has ravaged landscapes, contaminated ecosystems with toxic waste and resulted in widespread water pollution. Cyanide and mercury, two highly toxic substances, have been released freely into the environment as a result of dirty gold mining.
Toxic waste is a devastating consequence of dirty gold mining practices. Cyanide heap leaching is the cheapest way to extract gold and as a result, is commonly used around the world. The process leaves behind mounds of wasted rock and leaking toxic materials. And because leaching is a time consuming process that takes months, contamination of the surrounding environment with cyanide is nearly impossible to control.
Accidents involving cyanide have made the practice of heap leaching even more toxic. The United Nations Environment Program reports that more than a dozen reservoirs containing cyanide-laden mine waste collapsed from 1985 to 2000. This has led to devastating consequences in Romania, Ghana, Peru, Costa Rica, and other countries scattered around the world.
Cyanide is a rapidly acting and deadly chemical. Exposure to high levels of cyanide harms the brain and heart, and may cause coma and death. Exposure to lower levels may result in breathing difficulties, heart pains, vomiting, blood changes, headaches, and enlargement of the thyroid gland.
Disastrous spills have forced the gold industry to change how it handles cyanide by setting new standards for transporting and storing the chemical. New industry bodies have called on companies to submit to inspections. But the cyanide code is voluntary and not enforced by governments. And cyanide is not the only toxic waste associated with gold mining: when the rock disturbed by mines is exposed to rain and air for the first time, the newly exposed rock can contain sulfides that will react with oxygen to make sulfuric acid. This sulfuric acid also frees heavy metals like cadmium, lead and mercury, which are harmful to people and fish even at low concentrations.
Dirty Metals (No Dirty Gold)
Behind Gold's Glitter: Torn Lands and Pointed Questions (New York Times)
Below a Mountain of Wealth, a River of Waste (New York Times)
From as early as the 16th century, mercury has been used extensively for gold mining. It is estimated that between 1550 and 1880, nearly 200,000 tons of mercury were released in South America alone. Today, mercury poisoning is a global problem. Approximately 1,000 tons of mercury are released each year into the environment from informal or small-scale gold mining. Gold mining accounts for at least 30-40% of man made mercury pollution.
As much as two grams of mercury can be released into the environment for every gram of gold recovered. The mercury often enters river basins, spreading the mercury across national borders and into larger bodies of water. It is estimated that the Amazon basin receives 40 tons of mercury a year, while mining in Indonesia adds 150 tons to the Java Sea annually.
In March of 2008, an investigation into mercury emissions led to a state-ordered shutdown of the processing plant of a major gold mine in northeastern Nevada. Mercury from Jerritt Canyon and other gold mines in the state has contaminated lakes across the region.
Mercury vapor has serious health consequences for animals and humans. The amount of vapor released by mining activities has been proven to damage the kidneys, liver, brain, heart, lungs, colon and immune system. Chronic exposure to mercury may result in fatigue, weight loss, tremors, and behavioral and personality shifts.
Gold Mining as a Source of Mercury Exposure in the Brazilian Amazon (Environmental Research)
Water pollution has been a devastating byproduct of gold mining for hundreds of years. Fish in Sacramento and the San Francisco Bay continue to have elevated levels of mercury today from the mining process used by prospectors in the 19th century. Modern gold mining techniques, which consume vast quantities of fresh water, are just as damaging to nearby bodies of water. Long-term effects include acid mine drainage, which raises acidity levels in rivers and lakes, kills wildlife, and poisons drinking water supplies. Some mines then dispose of their toxic waste in rivers, lakes, and even oceans.
Cyanide and metal contamination produced at mines combine with acidic water in a particularly lethal mix. Acidic water is often present at gold mines and combines with cyanide to generate hydrogen cyanide gas, an even more potent poison than cyanide alone. Dirty gold mining has polluted water all over the world, leading to mass fish and wildlife kills.
Dirty Metals (No Dirty Gold)