gold mining

Small scale hydraulic mining operation on Nome beach during the gold rush 1904

U.S. EPA Mercury Capture System (video 4:59) – a solution to the severe health risks caused by mercury emissions from small-scale gold processing. Small scale gold buying and refining facilities, or gold shops, located in over 55 countries throughout the world, are an important part of the artisanal and small-scale gold production process, and are a major cause of air pollution from mercury. EPA and Argonne National Laboratory worked together to design a low-cost mercury capture system that is simple to build and install, using locally available materials. The system reduces mercury emissions by at least 80 percent.

What’s the problem?
mercury exposure from gold purification – small-scale mining and smelting under primitive conditions poses a major health hazard. A common method used by small miners in South America and other places is mercury extraction, which exploits the ability of mercury to “dissolve” gold and form an amalgam. This way, particles of gold can be separated from crushed ore and floated away. When the mercury is boiled away, the gold remains behind.

  • Ask – these small operations account for 700 tons (635 tonnes) of airborne mercury being released each year. The heavy metal falls back to earth, where it is inhaled, is picked up on exposed food on market stalls, and washes away into streams, where it enters the food chain.
  • Imagine
  • Design, Build – a converted steel drum condenses and recaptures the mercury vapor with 80 percent effectiveness.
  • Improve – refined design of the MCS and built prototypes, which cost about US$500 each.

That’s engineering

  • deposit – a natural accumulation or occurrence, especially of gold or ore