Acid Rock Drainage Characterization and Treatment, Western Pennsylvania

Sovereign was retained by a coal mining company to evaluate treatment alternatives for acid rock drainage (ARD) occurring at a former coal mine in western Pennsylvania. The project involves the decommissioning of an existing lime plant used for ARD and replacement of the lime plant with a hybrid-passive mine water treatment system. The hybrid-passive system is designed to treat pH 2.8 ARD at flows up to 1100 gpm.

The system consists of two Aquafix units, several open limestone channels (OLC), a manganese removal bed and several settling ponds. The system is gravity fed capitalizing on the site topography and placement of historic coal refuse piles along a natural drainage system. Engineering analysis indicates that the capital cost for replacing the lime plant is roughly equivalent to the hybrid-passive system capital cost but that operation and maintenance (O&M) costs are 75 to 80% less expensive for the hybrid-passive system. System installation is expected to be completed by spring 2015.