Pennsylvania Water Science Center



Chuck Cravotta


Coal-Mine-Drainage Projects in Pennsylvania

During 200 years of coal mining, Pennsylvania produced more than 25 percent of the nation's total coal output and presently ranks fourth in the nation in annual coal production by state. Coalfields are included within, or extend into, the four major river basins in Pennsylvania--the Ohio, Susquehanna, Potomac, and Delaware River Basins. Bituminous coal deposits underlie western and north-central Pennsylvania, and anthracite deposits underlie east-central and northeastern Pennsylvania (figure 1). Pennsylvania's bituminous coal is used mostly for electric-power generation; anthracite is used for electric-power generation and home heating.

Bituminous and anthracite coal fields in Pennsylvania
Figure 1.--Bituminous and anthracite coal fields in Pennsylvania

Streams and fisheries impacted by coal-mine drainage in Pennsylvania
Figure 2.--Streams and fisheries impacted by coal-mine drainage in Pennsylvania

(From U.S. Environmental Protection Agency)

Drainage from thousands of abandoned coal mines has contaminated more than 3,000 miles of streams and associated ground waters in Pennsylvania and is the most extensive water-pollution problem affecting the four major river basins in Pennsylvania. Because coal-mine drainage can contain toxic concentrations of acidity, metals, and sediment, many of the mining impacted streams contain "no fish" (figure 2). Consequently, Pennsylvania loses approximately $67 million annually that could be generated if sport fishing were restored in the affected streams. The estimated cost for restoring the damaged watersheds is $5 billion to $15 billion.

About half of the coal-mine discharges in Pennsylvania are acidic, with pH <5 (figure 3a; figure 3b). Generally, limestone or other calcareous strata that could neutralize acid are lacking or deficient at sites that produce acidic mine drainage (AMD). Although abandoned underground mines produce most of the AMD, some recently mined and reclaimed surface mines have produced AMD and have degraded local groundwater and surface-water resources. Acidic water produced at active mines must be neutralized to achieve pH 6-9 before discharge from a mine site to a stream is permitted. pH of bituminous coal-mine discharges in Pennsylvania
Figure 3a.--pH of bituminous coal-mine discharges in Pennsylvania

Figure 3b.--pH of anthracite coal-mine discharges in Pennsylvania

Studies by the U.S. Geological Survey (USGS) have documented the extent of surface-water and groundwater degradation associated with coal mining in Pennsylvania and have evaluated the effects of mining and reclamation practices and water-treatment methods intended to reduce contamination by mines. Recent USGS studies have been supported by funds and services from the U.S. Environmental Protection Agency (EPA); the U.S. Department of Interior, Office of Surface Mining Reclamation and Enforcement (OSMRE); the National Park Service (NPS); the West Virginia Department of Environmental Protection (WVDEP); the Pennsylvania Department of Environmental Protection (PaDEP); the Pennsylvania Department of Conservation and Natural Resources (PaDCNR); the Philadelphia Water Department; the Somerset County Conservation District; and the Schuylkill County Conservation District. Coal companies and the Pennsylvania State University also participated in these studies. Updates on current or recent projects are presented below:

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