How to Clean Up Acid Mine Drainage

Acid mine drainage is formed through a chemical reaction between sulphuric acid and rock ore. The sulphuric acid mixture leaches heavy metals from rocks creating toxic water and sludge flowing from mines. Both active and abandoned mines can have acid mine drainage problems contaminating groundwater, surface water and soil. There are several methods employed to clean up acid mine drainage. Implementation varies based on the level of contamination, cost and site conditions.

Instructions

• 1

  Characterize the site. Identify the type of mining and processing, nearby water sources and current ownership status. Site characterization requires the identification of waste disposal practices for byproducts such as rock ore and acid sludge. Identification of water sources determines the level of opportunity for water to come into contact with waste rock. Ownership status will determine the amount of resources available for cleanup projects.

• 2

  Collect samples to determine the scope of the contamination. Groundwater, surface water and soil samples within a mine's drainage area will reveal the level of contamination and geographic scope. Compare sample results to federal and state acceptable standards such as maximum contaminant levels (MCL) for groundwater. Any level over the MCL indicates contamination.

• 3

  Analyze treatment options by determining the level of contamination, site conditions and ownership status. For example, minimal contamination at abandoned mine sites will not receive intensive cleanup as opposed to potable groundwater contaminated from an active mine operation.

• 4

  Implement site-specific cleanup technology. An abandoned mine site may require institutional controls such as fencing, zoning and deed restrictions to prevent harm to humans and the environment. An active mine may implement cement-based stabilization of drainage sludge which adjusts the pH, making it less acidic, and locks up contaminants to prevent release into the environment.

• 5

  Continue to monitor the area. Continue sampling after cleanup technologies are implemented to determine effectiveness. Implement more intensive technologies if acid mine drainage continues to contaminate the environs. Keep fencing and signage visible and in good repair to warn the public about exposure to contaminants, especially hikers who may be interested in using contaminated water sources.