Hesperian Health Guides
Chemicals Used in Mining
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Chemicals used in mining and processing minerals contaminate the land, water, and air, causing health problems for workers and people living near mines. Toxic chemicals used in mining include:
- cyanide, sulfuric acid, and solvents for separating minerals from ore
- nitric acid
- ammonium nitrate and fuel oil (“ANFO”) used in blasting tunnels
- heavy metals such as mercury, uranium, and lead
- gasoline, diesel fuel, and exhaust fumes from vehicles and equipment
- acetylene for welding and soldering
Cyanide is used to separate gold from ore. In its pure form, cyanide has no color and smells like bitter almonds. It may lose this smell when it combines with other chemicals. It can be used in powder, liquid, or gas forms.
Cyanide is deadly when swallowed. An amount the size of a grain of rice is enough to kill a person. Exposure to low doses over a long time may cause a swelling in the throat (goiter), which can also be caused by malnutrition.
Cyanide is often spilled into waterways during gold mining, and when ponds filled with mine wastes burst and spill. Mining companies say that cyanide in water quickly becomes harmless. But this is true only when there is lots of sunlight and oxygen. Even then it leaves behind other harmful chemicals. If cyanide is spilled underground, or if the weather is cloudy or rainy, it can remain harmful for a long time, killing fish and plants along rivers and making water unsafe for drinking and bathing. Cyanide is so dangerous that it has been banned in some countries.
Sulfuric acid is a toxic chemical used in copper mining. It is also a byproduct of many kinds of mining, mixing with water and heavy metals to form acid mine drainage. Sulfuric acid smells like rotten eggs. Contact with sulfuric acid can cause burns, blindness, and death.
Chemicals used at mine sites can spill on the skin and clothes, splash in the eyes, or be breathed in as fumes. If someone is hurt, get medical help as soon as possible. (See how to treat chemical spills and chemical burns while waiting for help.)
The best way to prevent harm from toxic chemicals, including heavy metals, is to not use them. But there are also ways to prevent and reduce harm if toxics are still being used.
- Use protective equipment whenever possible.
- Wash your hands many times a day. Do not touch your face, smoke, or touch other people while working with or near toxics unless you wash your hands first.
- Demand that mine operators reduce dust and water pollution.
- Never eat where chemicals are being used, mixed, or stored.
- Store chemicals safely.
Many chemicals can cause fires, explosions, or release of toxic gases. Safe storage of chemicals can help prevent accidents and reduce harm at mine sites. Store chemicals:
- away from explosives, electrical sources, all sources of water, and motor vehicles.
- away from where people eat.
- in containers that are clearly labeled. If you move chemicals from one container to another, label the new container. Never put chemicals in containers used for food or drinks — someone may accidentally eat or drink the chemical. After a chemical container is empty, it should never be used for food or drinks, even if you wash it out.
- in strong, locked cabinets designed and labeled for chemical storage.