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Regulatory and Scientific Failures in Mine Permitting Result in Widespread Water Pollution, Increased Public Health Risks, and Costly Taxpayer-Funded Cleanups

Dec 7, Washington, DC — New scientific research unveiled today finds that faulty water quality predictions, mitigation measures and regulatory failures result in the approval of mines that create significant water pollution problems. Despite assurances from government regulators and mine proponents that mines would not pollute clean water, researchers found that 76 percent of studied mines exceeded water quality standards, polluting rivers, and groundwater with toxic contaminants, such as lead, mercury, arsenic and cyanide, and exposing taxpayers to huge cleanup liabilities. The release was issued by the Washington, DC-based conservation group EARTHWORKS and conservation groups in as many as ten western states affected by mining.

“Without correction, the human, environmental, and financial costs of these regulatory failures will continue to grow as more mines are permitted,” said report author and mining engineer Jim Kuipers. “Where predictions of water quality at mine sites are concerned, the scientific process is broken and must be fixed.”

The first-of-a-kind reports, “Comparison of Predicted and Actual Water Quality at Hardrock Mines,” and “Predicting Water Quality Problems at Hardrock Mines: Methods and Models, Uncertainties, and State-of-the-Art,” by Kuipers, P.E., and geochemist Ann Maest, Ph.D., analyzed water quality predictions and outcomes at 25 representative metal mines permitted in the United States during the last 25 years.

The scientists found that predictions of mining’s impact on clean water were made without checking the results of past predictions. They also found that predictions were often made using inadequate information, incorrectly applied. Not surprisingly, mitigation measures based on the inaccurate predictions also typically failed to protect clean water.

Among the researchers’ findings for the 25 mines examined in depth:

  • 76 percent of mines exceed groundwater or surface water quality standards
  • 93 percent of mines that are near groundwater and have elevated potential for acid drainage or contaminant leaching exceeded water quality standards[1]
  • 85 percent of mines that are near surface water and have elevated potential for acid drainage or contaminant leaching exceeded water quality standards
  • Water quality standards for toxic heavy metals, such as lead, mercury, cadmium, copper, and zinc, were exceeded at 63 percent of mines.
  • Mitigation measures predicted to protect clean water failed at 64 percent of the mines.

“Regulators and mining companies have a responsibility to ensure that sound science and widely available, state-of-the-art methods are used to prevent pollution at mine sites,” said Maest. “Changes in permitting evaluations are needed at current and future mines to keep our waters clean and our fisheries viable.”


The researchers also found that mines located near surface or groundwater that tapped ore bodies with high potential for acid-generation or contaminant leaching, and near water resources were at high-risk of resulting in water pollution. This finding in particular has serious implications for controversial new mines now being proposed, or in permitting including:

  • Pebble gold-copper mine in southwest Alaska at the headwaters of Bristol Bay, home to the world’s largest salmon runs.
  • Atlanta gold mine in Idaho adjacent to the Boise River, which provides Boise with more than 20 percent of its municipal water
  • Rock Creek silver-copper mine in northwest Montana near the Clark Fork River and underneath the Cabinet Mountains Wilderness.

“With dozens of new mines and mine expansions in the pipeline, this report could not have come at a better time,” said Alan Septoff, Director of Research at EARTHWORKS, which commissioned the studies. “Action on these findings by regulators and mining companies should result in cleaner water, healthier economies, and more responsible mining.”

Sustained increases in metal prices, driven in part by growing demand from China, have triggered a sharp increase in the number of new mines and mine expansions being proposed in the United States. New mining claims filed in 2006 for mines on federal public lands are on track to more than quadruple since 2002.

Based on the researchers’ findings, the groups releasing the studies offered the following recommendations:

  • Better screening of high-risk mines — particularly those near water resources that have the potential to create pollution from acid drainage or metal leaching.
  • Take a precautionary approach to mine permitting and plan for worst-case scenarios.
  • Undertake a thorough review of water quality predictions at all existing mines.
  • Keep the public informed, make risks transparent.
  • Prevent conflicts-of-interest between mine proponents and expert consultants who prepare predictions and analyses.

The reports have been extensively peer-reviewed and presented at five major conferences, including: U.S. EPA’s Hardrock 2006 Conference in Tucson, Arizona; Society for Mining, Metallurgy, and Exploration’s 2006 Annual Meeting in St. Louis; and the Mine Design, Operations and Closure Conference in Fairmont Hot Springs, Montana, also in 2006.