• Mining pollution: Does gold mining emit mercury?

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    Mining may emit mercury, especially in the processing of ores. Mining pollution control measures can decrease mercury emissions and in recent decades mercury emissions in Europe and North America have dropped significantly.

    Mercury is an element that is naturally present in metal ores in varying amounts. In many mining areas mercury is not present and is not emitted. Where mercury is present, it can be released into the air through mining and processing these ores, leading to concerns about possible human and environmental impacts.

    Mining-related Mercury Emissions and Trends

    Mining and refinement of metals is the third largest man-made source of mercury emissions. The United Nations Environment Program (UNEP) estimates that large-scale gold production contributes 6-7% of man-made mercury emissions, and other metal mining and processing contributes an additional 10%.[1, p. 17]

    Mercury emissions in developed countries have decreased in recent decades as new mining pollution control mechanisms are used to remove mercury from emissions:

    • Most major smelters use pollution controls with removal rates of up to 95%[1, pp.16-17]
    • In Canada, mercury emissions decreased 84% between 1990 and 2009[2], due in part to large reductions in emissions from the base metals sectors and the introduction of new technologies[3]
    • In the U.S., mercury emissions decreased 80% between 2002 and 2005 at the four largest gold mines as part of the Voluntary Mercury Reduction program[4]
    • The largest decreases in mercury emissions have been in Europe due to improved control measures, economic changes, and changes in processing and consumption[1, p.21]

    Case Study: The Voluntary Mercury Reduction Program in the US

    Nevada’s four largest gold mining companies formed a partnership with the Nevada Division of the EPA in 2002. Their goal was to reduce mercury emissions significantly, quickly, and permanently while minimizing the costs of regulation.

    The impacts of this partnership were significant since at that time, the participants produced 90% of mercury air emissions reported by Nevada gold mines in the Toxic Release Inventory.[5] Nevada is the largest producer of gold in the U.S. (80% of total U.S. production in 2002).

    The Nevada mines installed a variety of pollution control technologies voluntarily and faster than what would have been required through regulation. The companies achieved an 80% reduction in emissions by 2005, a significant reduction in three years and well in advance of targets.[4]

    Show References


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

    2Canada, Environment Canada,. 2009 Air Pollutant Emission Summaries and Historical Emission Trends. March 15, 2011 [cited 2011 August 12]; Available from: http://www.ec.gc.ca/inrp-npri/default.asp?lang=En&n=2DAFE231-1#Highlights.

    3Canada, Environment Canada. Risk Management Strategy for Mercury. 2010 [cited 2011 November 1]; Available from: http://www.ec.gc.ca/doc/mercure-mercury/1241/index_e.htm#figure7.

    4United States, Environmental Protection Agency [EPA]. Voluntary Mercury Air Emission Reduction Program (VMRP) EPA, State of Nevada Collaborate with Nevada's Gold Mines. [cited 2011 August 9]; Available from: www.epa.gov/region9/toxic/mercury/pdf/vmrp-final.pdf.

    5United States, Environmental Protection Agency [EPA]. Nevada Mining Partnership Program: Region 9 Innovations. April 20, 2011 [cited 2011 August 8]; Available from: http://www.epa.gov/region9/innovations/mining.html.

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