ODNR Division of Oil and Gas Resources Management - Abandoned Mine Land (AML)

Restoring Water Resources in Streams Impacted by Acid Mine Drainage

The Division of Mineral Resources Management supports and assists local efforts aimed at restoring streams to their pre-mining ecological condition and to construct acid mine drainage (AMD) remediation projects that demonstrate cost-effective environmental benefits.


Acid Mine Drainage (AMD)
AMD is water from areas that have been mined for coal or other mineral ores. It often contains dilute sulfuric acid and high levels of heavy metals such as iron, aluminum and manganese. The water has a low pH because of its contact with sulfur-bearing material and is harmful to aquatic organisms.

Investigation
Locating the source of all mine drainage in a watershed is critical to understanding which sites are responsible for the majority of pollutant loads. This enables the selection of the least expensive and most effective design for restoring streams to a healthy condition. A minimum of one year of investigation and sampling is usually necessary to understand the seasonal flow patterns of abandoned mine sites.

Design of the correct system for each mine site to be reclaimed takes additional time for surveying, drilling, sample analyses and design plan preparation. Along with landowner negotiations and leveraging funding from outside partners, considerable time can be expended before reclamation or treatment even begins.

Abatement
Source control is the preferred method of abatement. It is a one-time cost and eliminates the problem with little to no future maintenance obligation, such as

  • reclamation of stream capturing subsidence
  • reclamation of toxic spoil
  • remining

Treatment is not desired but necessary for areas where source control is not feasible. Treatment can be passive (requiring little operation or maintenance) or it can be active (requiring regular operation and maintenance), including

  • lime doser
  • wetland
  • steel slag leach bed
  • anoxic limestone drain
  • limestone rock channel, rock dam and leach bed
  • vertical flow pond (composed of limestone and compost)