Evaluating the Potential Impacts of Mine Wastes on Ground and Surface Waters

There are two steps in evaluating potential mine waste impacts on ground and surface waters. Characterize the mine waste (characterization methodologies) and assess potential impacts (assessment strategies). One or both may be required for mine permitting, operation and closure. The first step is to characterize the waste. Determine if it has the potential to release chemical constituents or acid rock drainage to the environment. If no potential exists for release to the environment, the evaluation process is complete. A monitoring plan is then established. If the potential exists for release of chemical constituents or acid rock drainage to the environment, a strategy to evaluate potential impacts must be implemented. Strategies discussed here to evaluate potential impacts were developed during investigations at precious metal and base metal mines in Nevada. Water resources in Nevada consist mostly of ground water. So the strategies discussed focus on potential impacts to ground water. However, several of these strategies also apply to assessing potential impacts to surface water. Implementing these strategies has helped determine the potential for impact and has been successful in permitting mine expansion as well as allowing continued operation and obtaining mine closure at several mine sites in Nevada. These strategies were carried out in accordance with Nevada Division of Environmental Protection (NDEP) regulations and through the National Environmental Policy Act (NEPA)