It might be a relatively small slice of the mining industry, accounting for less than 20% of global gold production, but artisanal and small-scale gold mining (ASGM) operations are the biggest source of mercury pollution in the world.
The sector punches well above its weight producing almost 40% or nearly 830 tonnes of the 2,200 tonnes of total global mercury emissions released each year.
Although mercury is a natural element that has been used in gold mining for centuries, it is highly toxic to people and the environment. Its trade and use have been strictly regulated in recent years.
Clean Earth Technologies Group CEO Kevin Fell said, “More than 100 million people around the world, many living in poverty, rely on artisanal mining to feed their families.
“Most of the gold producers use primitive mercury and cyanide-based extraction processes that leave people with debilitating health effects and huge problems with water, soil and air pollution.
“These miners make an important economic contribution, particularly in developing countries, so there are huge drivers for them to continue operating.
“It is crucial that we give them access to safe, economical and sustainable processing technologies and that is a core focus for Clean Mining, a part of our Clean Earth Technologies group.”
Damaging the environment
These small gold miners are dying because they use mercury as an amalgam when panning for gold. The mercury-gold amalgam is burnt to remove the mercury, releasing toxic vapour into the atmosphere.
Mercury released into the environment pollutes the surrounding air, soil and water which often affects nearby populated areas, farming land and fishing waters.
Once released, mercury can stay in the environment for hundreds – even thousands – of years, affecting the reproduction, growth and neurodevelopment of wildlife. Mercury exposure can also lead to behavioural changes which threatens the survival of some species, as well local biodiversity.
About 15 million people in 80 countries are involved in the search for gold via artisanal mining techniques, and it is estimated that three million of them are women and children.
These gold miners are at high risk of danger of dying through mercury exposure through inhalation, absorption and ingestion. If ingested, elemental mercury (the form used in mineral processing) can cause gastrointestinal problems, gingivostomatitis (a highly contagious mouth infection), photophobia (eye sensitivity, pain or discomfort when exposed to light), tremors and nerve and kidney damage.
Further health concerns include neuropsychiatric symptoms like anorexia, depression, fatigue, insomnia, memory loss and nervousness.
With ASGM centres often located in highly populated areas, there is a significant broader community risk of direct, high-level elemental mercury exposure through inhalation. This level of exposure has been linked to lung inflammation, pulmonary oedema, respiratory failure and death.
Contaminated farmland and fishing waters increase the risk of human mercury intoxication. As mercury makes its way into water sources, biogeochemical interactions convert it into methylmercury. This form of mercury is more easily absorbed into the body and is associated with neurologic disease.
A better way
Clean Mining’s breakthrough processing technology has the potential to transform gold processing worldwide, bringing safe, economical and sustainable solutions that are appropriate for large scale miners or even the world’s smallest operators.
The company’s cyanide and mercury-free processing options use an environmentally safe and reusable reagent—containing a non-flammable and water-soluble compound called thiosulphate—to dissolve gold from mined ore.
It is a solution the world’s miners have been dying to discover.
Clean Mining is part of the Clean Earth Technologies Group.