Ultra High Temperature Pyrometallurgy(TM), UHTP(TM): Enabling Small-Scale Mining Without Mercury or Cyanide

Artisanal and small-scale mining (ASM) plays a vital role in the livelihoods of millions worldwide, especially in developing countries. However, the widespread use of mercury in small-scale gold mining has caused severe environmental pollution and health hazards. Mercury amalgamation, the traditional method to extract gold – roughly 50% of the world’s gold is still produced this way, releases toxic mercury vapours into the environment, endangering miners, their families, and surrounding communities. Cyanide, though used more in industrial settings, also poses significant toxicity risks and requires strict regulation.

The urgent global mandate to reduce and eliminate mercury use in small-scale mining, as emphasised by the Minamata Convention on Mercury, has driven efforts to find safer, more sustainable alternatives. Among these, Ultra High Temperature Pyrometallurgy^TM (UHTP^TM) emerges as a transformative technology that can enable small-scale mining without mercury or cyanide, offering a chemical-free, environmentally friendly, and efficient method of metal extraction.

The Challenge of Mercury and Cyanide in Small-Scale Mining

• Mercury Use in Small-Scale Mining: Mercury is traditionally mixed with crushed gold ore to form an amalgam, which is then heated to vaporise mercury and recover gold. This process is simple and inexpensive but highly dangerous. It results in the release of large quantities of mercury into the air, soil, and water. Globally, artisanal and small-scale gold mining is the largest source of mercury pollution, releasing over 2,000 tonnes annually[4][7].
• Health and Environmental Impacts: Mercury exposure causes neurological damage and other serious health issues, especially among miners and children in mining communities. Environmental contamination affects biodiversity and water quality, with long-lasting consequences.
• Cyanide Use: While cyanide leaching is more common in industrial mining, some small-scale operations also use cyanide as a mercury alternative. Cyanide is toxic and poses risks of spills and contamination, requiring careful handling and regulatory oversight[2].
• Global Efforts to Eliminate Mercury: The Minamata Convention calls for the reduction and elimination of mercury use in artisanal and small-scale gold mining. Many miners are adopting mercury-free techniques such as gravity concentration, direct smelting, and borax smelting, which are safer and often more efficient[1][3][5][6].

How UHTP^TM Enables Small-Scale Mining Without Mercury or Cyanide

Ultra High Temperature Pyrometallurgy^TM (UHTP^TM) uses plasma or other advanced heat sources to generate extremely high temperatures, allowing the direct thermal digestion of ores. This process fundamentally changes how metals are liberated and recovered:

• Chemical-Free Extraction: UHTP^TM does not rely on mercury amalgamation or cyanide leaching. Instead, it uses intense heat to break down complex ore matrices, including amorphous and encapsulated minerals, releasing gold and other valuable metals without toxic chemicals [IPRI.Tech].
• Effective on Complex Ores: Many gold ores in small-scale mining contain gold locked in difficult-to-treat materials that resist traditional chemical extraction. UHTP^TM’s plasma-assisted digestion can process such ores efficiently, enabling small-scale mining without mercury even in challenging deposits.
• Environmental Safety: By eliminating mercury and cyanide, UHTP^TM prevents toxic emissions and contamination. The process operates in a controlled environment, minimising air and water pollution, thus protecting miners, their families, and ecosystems.
• Higher Recovery Rates: Traditional mercury amalgamation recovers about 88% of gold, while direct smelting and other mercury-free methods can reach 95% or more[3]. UHTP^TM, with its advanced thermal capabilities, can potentially improve recovery further by liberating even fine and encapsulated gold particles.
• Rapid Processing: UHTP^TM can process ores faster than chemical leaching methods, reducing processing time from days to hours or minutes, which benefits small-scale miners by increasing throughput and income.

Complementary Mercury-Free Techniques in Small-Scale Mining

While UHTP^TM represents a cutting-edge solution, it complements other mercury-free methods already in use or promoted in small-scale mining:

• Gravity Concentration: Techniques such as panning, sluicing, shaking tables, and centrifuges concentrate gold without chemicals, forming a concentrate that can be further processed without mercury[1].
• Direct Smelting: This method replaces mercury by smelting gold concentrates directly, recovering fine gold particles and avoiding toxic emissions[3].
• Borax Smelting: Introduced in the Philippines over 30 years ago, this method uses borax as a flux to lower the melting point of gold concentrates, enabling mercury-free extraction with simple equipment. It has been successfully adopted by thousands of small-scale miners and shown to recover up to twice as much gold as mercury amalgamation [5][6][8].

The Broader Impact of UHTP^TM on Small-Scale Mining Communities

• Health Benefits: By enabling small-scale mining without mercury, UHTP^TM reduces miners’ exposure to toxic mercury vapours and cyanide, improving community health and safety.
• Environmental Protection: UHTP^TM prevents mercury pollution of air, water, and soil, helping preserve biodiversity and ecosystem services critical to local livelihoods.
• Economic Advantages: Mercury-free gold is often more marketable and can fetch higher prices. UHTP’^TMs efficient recovery methods can increase gold yields, boosting miners’ incomes.
• Compliance and Formalisation: Adoption of UHTP^TM aligns with international regulations and supports the formalisation and modernisation of artisanal mining, which is essential for sustainable development[4].

Challenges and Future Directions

• Access to Technology: UHTP^TM requires specialised equipment and technical expertise. Scaling this technology for widespread use in remote small-scale mining communities will need investment, training, and support.
• Integration with Existing Practices: Transitioning from mercury amalgamation to UHTP^TM or other mercury-free methods requires education, community engagement, and demonstration of economic benefits.
• Policy and Support: Governments and international agencies must support the dissemination of UHTP^TM and mercury-free technologies through funding, regulation, and capacity building.

Summary and What Comes Next

Ultra High Temperature Pyrometallurgy^TM (UHTP^TM) offers a groundbreaking pathway for small-scale mining without mercury or cyanide. By harnessing plasma-based high-temperature processes, UHTP^TM can efficiently and safely extract gold and other metals from complex ores without the environmental and health hazards of traditional chemical methods.

This technology complements existing mercury-free techniques like gravity concentration, borax smelting, and direct smelting, collectively enabling a future where small-scale mining is sustainable, safe, and free from toxic chemicals. As global efforts to eliminate mercury use intensify, UHTP^TM stands as a promising solution to transform artisanal and small-scale mining into a cleaner, healthier, and more prosperous sector.

For more information on UHTP^TM and mercury-free small-scale mining technologies, refer to IPRI.Tech and international environmental agencies’ resources on artisanal mining without mercury.

References

1. https://www.epa.gov/international-cooperation/artisanal-and-small-scale-gold-mining-without-mercury
2. https://cen.acs.org/policy/global-health/push-mine-gold-without-mercury/102/i38
3. https://mbmmllc.com/direct-smelting-an-alternative-to-mercury-use-in-gold-mining/
4. https://www.unep.org/globalmercurypartnership/what-we-do/artisanal-and-small-scale-gold-mining-asgm
5. https://www.scirp.org/(S(vtj3fa45qm1ean45%20vvffcz55))/journal/paperinformation?paperid=45773
6. https://pmc.ncbi.nlm.nih.gov/articles/PMC6221499/
7. https://19january2017snapshot.epa.gov/international-cooperation/artisanal-and-small-scale-gold-mining-without-mercury_.html
8. https://ehp.niehs.nih.gov/doi/abs/10.1289/isee.2020.virtual.P-0197
9. https://www.sciencedirect.com/science/article/abs/pii/S0959652605000764
10. https://pmc.ncbi.nlm.nih.gov/articles/PMC6257171/

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The future of mining with UHTP^TM and PAD(^TM