• Does mining use mercury?

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    Canadian mining operations in Canada and abroad do not use mercury and, where mercury is naturally present in ores, take precautions to prevent its release into the environment. Mercury use by the artisanal and small-scale mining sector is a growing environmental concern in developing nations.


    Mercury Use in Gold Processing

    Humans have mined mercury since the Roman times and it is still used in products such as fluorescent lights, energy saving lamps, and electronic devices.[1, p.12] Mercury is also a by-product from the mining and refining of other metals including gold, silver and zinc [2, p.117] although most of this can be captured and reused.[1, p. 11]

    Mercury was once used throughout the world in gold processing. It was employed to assist with the extraction of gold and silver from ore. This process has since been replaced by more efficient and less environmentally damaging techniques such as cyanide leaching in large-scale and industrial mining.

    In developing nations, mercury pollution is increasingly a result of illegal or artisanal mining and is an ongoing and growing concern.


    Mercury and the Environment

    Mercury is highly toxic and can cause serious illness and death in humans and animals. Globally, for health and environmental reasons, efforts are being made to reduce the use and release of mercury.

    Mercury---also known as quicksilver--is an element found in nature in various forms. It is released into the environment through natural processes such as volcanic eruptions, the weathering of rocks, and forest fires.[2, p.11] Mercury is also released through human activities and industrial processes.

    Because it is an element, mercury does not break down in the environment. Instead, it is cycled between the atmosphere, land, and water, and can travel large distances from the original source[2, p.110]. Mercury can also build up in humans and animals and become highly concentrated in the food chain.[3] This is a problem since low levels of mercury exposure can build up over time until concentrations are high enough to be harmful.


    Mercury in the Developing World

    Mercury is still used to extract gold in the developing world despite safer alternatives and the elimination of mercury use by large-scale mining operations. It is used by artisanal and small-scale miners (ASM), often in unsafe and environmentally damaging ways.[1, p.13] The United Nations Industrial Development Organization estimates that 1,000 tons of mercury is released into the air, soil, and water each year by this sector.[4, p.9]

    Mercury is used to purify gold from ore in a process called amalgamation. Miners and their families often inhale toxic mercury vapors through this process, and mercury can pollute homes and communities.[5] It can also contaminate the land and water where gold processing occurs.

    Global initiatives such as the UN-led Global Mercury Project are trying to help miners in developing countries adopt best practices and reduce mining pollution caused by the use of mercury. Members of the International Council on Mining & Metals (ICMM) have also committed to promote the responsible use of mercury and partner with governments to transfer low- or no-mercury processing technologies to the ASM sector.[6]



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    References

    1UNEP Chemicals Branch, The Global Atmospheric Mercury Assessment: Sources, Emissions and Transport, 2008, UNEP-Chemicals.

    2UNEP Chemicals Branch, Global Mercury Assessment, 2002, UNEP Chemicals.

    3Canada, Environment Canada. About Mercury. 2010 March 25, 2010 [cited 2011 October 31]; Available from: http://www.ec.gc.ca/mercure-mercury/default.asp?lang=En&n=D64997D2-1.

    4Communities and Small-Scale Mining (CASM), International Finance Corporation‘s Oil, Gas and Mining Sustainable Community Development Fund (IFC CommDev), and International Council on Mining & Metals [ICMM], Working together: how large-scale miners can engage with artisanal and small-scale miners, 2009, ICMM: www.icmm.org.

    5Siegel, S. Threat of Mercury Poisoning Rises with Gold Mining Boom. Yale Environment 360, 2011.

    6International Council on Mining & Metals [ICMM], Mercury Risk Management:Position Statement February 2009, 2009.

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