What is Artisanal and Small-Scale Gold Mining (ASGM)?

Artisanal and small-scale gold mining refers toMining activities that use rudimentary techniques to extract and process minerals and metals, including gold, from primary and secondary deposits. While providing livelihoods for millions of people worldwide, particularly in developing countries, this informal mining sector often operates with minimal regulation and oversight.

Approximately 15-20 million miners worldwide work in artisanal gold mining operations, with an additional 100 million people in over 70 countries depending on this sector for their livelihood. These small-scale miners produce roughly 15-20% of the world's gold annually, utilizing simple tools and traditional methods passed down through generations.

The Mercury Problem

Mercury has been used in gold mining for centuries due to its unique ability to form an amalgam with gold. In ASGM, miners mix mercury with crushed ore containing gold particles. When the mercury-gold amalgam is heated, the mercury vaporizes, leaving behind purified gold. This simple and inexpensive method makes mercury appealing to small-scale miners with limited technical knowledge and financial resources.

Mercury Cycle in Gold Mining

Mercury added to ore Forms amalgam with gold Amalgam heated Mercury vapor released into atmosphere & gold recovered

However, this practice releases approximately 1,000 tons of mercury annually into the environment, making artisanal gold mining the largest single source of anthropogenic mercury emissions worldwide. The Minamata Convention on Mercury, a global treaty adopted in 2013, specifically targets this sector as a priority for mercury reduction.

Health Impacts of Mercury Exposure

Mercury is a potent neurotoxin that affects the nervous, digestive, and immune systems, as well as lungs, kidneys, skin, and eyes. The World Health Organization considers mercury one of the top ten chemicals of major public health concern.

Direct Exposure to Miners

Miners face direct mercury exposure through inhalation of mercury vapor during the burning process and through skin contact when handling the metal. Acute exposure can cause:

  • Chest pains, difficulty breathing, and coughing
  • Nausea, vomiting, and diarrhea
  • Muscle weakness and tremors
  • Changes in vision or hearing
  • Headache and dizziness

Chronic Health Effects

Long-term exposure to mercury, even at low levels, can result in severe health consequences:

  • Neurological and behavioral disorders including tremors, insomnia, memory loss, and neuromuscular effects
  • Developmental delays in children exposed prenatally
  • Immune system suppression
  • Kidney damage
  • Cognitive and motor dysfunction

Women of childbearing age and children are particularly vulnerable. Mercury can cross the placental barrier, affecting fetal development. Breastfeeding can also pass mercury to infants, potentially causing neurodevelopmental delays and cognitive deficits.

Wider Community Exposure

The impact extends beyond miners to entire communities through:

  • Air pollution from mercury vapor during amalgam burning
  • Water contamination from improper disposal of mercury-laden tailings
  • Fish consumption mercury accumulates in aquatic food chains, bioaccumulating in fish that may be caught and eaten by community members
  • Soil contamination affecting agricultural lands

Environmental Consequences

The release of mercury during ASGM creates lasting environmental damage:

Environmental Impact Facts:

  • Released mercury can travel globally, contaminating ecosystems far from the original source
  • Mercury transforms into methylmercury in aquatic environments, a highly toxic organic form
  • One gram of mercury can pollute a 20-acre lake to the point where fish consumption advisories are necessary
  • Mercury persists in the environment for decades to centuries, continuing to cycle through ecosystems

The environmental degradation extends beyond mercury pollution:

  • Deforestation as miners clear land for operations
  • River sedimentation from erosion and mining waste
  • Water pollution from other mining chemicals and heavy metals
  • Loss of biodiversity in affected ecosystems

Alternative Technologies and Practices

Several mercury-free and mercury-reduction techniques exist that can help reduce environmental and health impacts:

Gravity Concentration Methods

Devices like centrifugal concentrators, shaking tables, and spiral concentrators can recover gold based on density differences without mercury. These can recover up to 90-95% of gold in the ore.

Flotation Techniques

Flotation uses chemical reagents to create bubbles that attach to gold particles, carrying them to the surface for collection. This method can be effective for fine gold that gravity methods may miss.

Cyanide Leaching with Proper Management

While introducing new environmental concerns, cyanide leaching can be more effectively contained and managed than mercury when proper engineering controls are in place.

Mercury Capture Technologies

Retorts and fume hoods can capture up to 95% of mercury vapor during the burning process, allowing it to be reused rather than released into the air.

Societal and Economic Dimensions

The issue of ASGM and mercury use cannot be separated from broader social and economic factors:

Livelihood Dependence: For many impoverished communities, ASGM provides essential income that supports entire families and regions. Simply eliminating these operations without alternatives creates humanitarian concerns.

Lack of Formalization: Many ASGM operations areIllegal or informal, limiting access to training, financing, and support for better practices. Formalization efforts are often complicated by unclear regulations, corruption, or bureaucratic hurdles.

Gold Supply Chain: Artisanal gold enters global supply chains, making it difficult for consumers to know whether their jewelry or electronics contain mercury-extracted gold. Certification schemes like Fairmined are working to provide mercury-free options.

Policy Approaches

Effective mercury reduction requires multi-faceted policy approaches:

  • Formalization: Recognizing and integrating ASGM into the formal economy improves regulation while providing miners with legal protections and access to markets.
  • Education and Training: Training miners in mercury-free techniques, environmental management, and occupational health reduces mercury use while preserving livelihoods.
  • Financial Support: Providing access to credit and financing for miners to invest in cleaner technologies is essential for adoption of alternatives.
  • Regulation and Enforcement: Clear regulations limiting mercury use, proper disposal requirements, and enforcement mechanisms help reduce mercury releases.
  • Market Mechanisms: Creating premium markets for responsibly-mined gold and implementing due diligence requirements can incentivize better practices.
  • Health Services: Establishing mercury screening programs and treatment services for affected communities addresses existing contamination impacts.

Success Stories

Several regions have demonstrated progress in reducing mercury use in ASGM:

In Peru, government interventions combined with NGO support have helped thousands of miners adopt retorts and other mercury capture technologies while continuing to earn their livelihoods.

Kenya has implemented progressive policies that focus on formalization of the sector while providing miner training on mercury-free techniques, resulting in measurable reductions in mercury use.

The Partnership for Responsible Jewelry has worked to connect artisanal miners using responsible practices with premium jewelry markets, creating economic incentives for mercury reduction.

Conclusion

Addressing mercury exposure in artisanal and small-scale gold mining requires balancing environmental and health objectives with the economic realities that drive miners to use mercury. Success comes through approaches that respect miner livelihoods while offering practical alternatives to mercury use.

The global community, through instruments like the Minamata Convention, has recognized the urgency of this issue. But implementation requires resources, political will, and most importantly, the engagement of mining communities themselves as partners in the transition to responsible mining practices.

Tackling the mercury problem in ASGM is not just an environmental imperativeit's a matter of public health, social justice, and sustainable development for millions of people worldwide.