2006 study of Water Quality at modern hardrock mines

The IMM project application clearly states that the mine will comply with all regulations pertinent to water discharge into Wolf Creek from dewatering and that the mine will store any tailings on site in such a way as to prevent any leaching from the tailings into the creek. All mines within the US are required to certify that they comply with the Clean Water Act and all other applicable local and state environmental requirements.

However, in actual fact, based on a 2006 study conducted by Ann Maest, PhD and Jim Kuipers, PE, an overwhelming majority of mines fail to comply. The studies are entitled: “Comparison of Predicted and Actual Water Quality at Hardrock Mines: The reliability of predictions in Environmental Impact Statements” and “Predicting Water Quality at Hardrock Mines: Methods and Models, Uncertainties, and State-of-the-Art.”

Below we present the highlights from these disturbing but extremely important and scientific studies. A white paper, entitled “Predicting Water Quality Problems at Hardrock Mines, A Failure of Science, Oversight, and Good Practice” by Alan Septoff, Dec. 2006 which can be found in its entirety here is the basis for the information presented below.

A failure of science, oversight and good practice

This paper is a summary, written for the layperson, of the findings of a two-year research study on the accuracy of water quality predictions at hardrock mines. The study, conducted by Jim Kuipers and Ann Maest , brings to light a decades-long failure by government regulators, industry, and consultants to recognize and correct deficient procedures and methods for predicting contamination of water at hardrock mines. Kuipers and Maest have discovered that, in practice, there is a failure to compare predictions made before the mines are permitted with the actual results. The predictive modeling results are not adjusted to account for real-life failures - this, despite the fact that at the vast majority of mines, problems were worse than predicted. Establishment of credibility in modeling requires that the predictions be tested, and then the models adjusted based on the results. This process appears broken when it comes to predicting the impact of mines on water quality for mine permits.

Do predicted water quality impacts match reality?

The answer, in short, is no. The Comparison Report reveals:

  • 100 percent of mines predicted compliance with water quality standards before operations began (assuming pre-operations water quality was in compliance).
  • 76 percent of mines studied in detail exceeded water quality standards due to mining activity.
  • Mitigation measures predicted to prevent water quality exceedances failed at 64 percent of the mines studied in detail.

Potential & Predicted Water Quality

The authors discovered a two-tiered system for water quality predictions, one-tier of which was based not on sound science, but on unsupported “good faith” projections.

The two tiers of “predictions” made about water quality in environmental assessments are referred to by the authors as “potential” and “predicted” water quality:

  • Potential water quality is the expected water quality conditions in the absence of mitigation efforts by the operator.
  • Predicted water quality takes the effect of mitigating measures into account. It is what mine operators forecast actual water quality will be during and after operations.

All the environmental reviews analyzed in the Comparison Report predict acceptable water quality after mitigation at mines where water quality standards were met before mining began. If this prediction were not made, the regulatory agency would not be able to approve the mine.

However, inadequate information was provided to demonstrate how the mitigation measures would actually prevent water quality impacts. Therefore, regulators were generally accepting the final water quality predictions on “faith.”

Prediction vs. Reality: Overall Water Quality Impacts to Ground and Surface Water

Of the 25 mines sampled:

  • 76% of mines polluted groundwater or surface water severely enough to exceed water quality standards.
  • 60% of mines polluted surface water severely enough to exceed water quality standards.
  • 52% polluted groundwater severely enough to exceed water quality standards.

Predictions vs. Reality: the Failure of Mitigation

In the cases where water quality standards were exceeded, in some cases the mine proponent anticipated the potential for pollution and prepared mitigation strategies (e.g. a mine waste dump lined with plastic to prevent acid drainage leaching into groundwater). Predictions of the efficacy of mitigation were no more reliable than overall predictions of water quality:

  • 73% of mines exceeded surface water quality standards despite predicting that mitigation would result in compliance. The other 4 mines didn’t predict the need for mitigation.
  • 77% of mines that exceeded groundwater quality standards predicted that mitigation would result in compliance. The other 3 mines didn’t predict the need for mitigation.

Predictions vs. Reality: Mines near Water with Elevated Acid Drainage or Contaminant Leaching Potential are High Risk

Some mine projects are so high risk that water quality exceedances are a near certainty: those mines that are both near groundwater or surface water resources, and possess an elevated potential for acid drainage or contaminant leaching.

  • 85% of the mines near surface water with elevated potential for acid drainage or contaminant leaching exceeded water quality standards
  • 93% of the mines near groundwater with elevated potential for acid drainage or contaminant leaching exceeded water quality standards.
  • Of the sites that did develop acid drainage, 89% predicted that they would not.

Water Quality Pollutants

Of the 76% of mines that exceeded water quality standards, the pollutants that exceeded standards were as follows

  • Toxic heavy metals such as lead, mercury, cadmium, copper, nickel or zinc exceeded standards at 63% of mines.
  • Arsenic and sulfate exceeded standards at 58% of mines.
  • Cyanide exceeded standards at 53% of mines.

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