Longwall mining, subsidence, and protection of water resources in Virginia

Abstract

In the coalfields of Southwest Virginia, Iongwall technology accounts for an increasing proportion of underground coal mine production. lt is a highly productive, capital intensive method that provides a degree of mine safety greater than conventional methods. However, subsidence caused by Iongwall mining has been blamed for, among other things, damaging wells, springs, and streams above the mines. Surface landowners whose water supplies are affected by Iongwall mines may negotiate with mining companies for compensation, or they can seek redress in the courts. At the same time, the U.S. Surface Mine Control and Reclamation Act (SMCRA) provides a framework for regulation of the environmental effects of coal mining, including hydrologic effects. The Department of Mines, Minerals, and Energy, Division of Mined Land Reclamation (DMLR) is responsible for implementation of Virginia’s primacy program under SMCRA.

This research has assessed the potential of Iongwall mining to damage the groundwater and surface water resources In Southwest Virginia; and examined whether existing laws and regulations, as implemented, provide an adequate and appropriate level of protection to both water property rights and the environment. Methods included review of published and ongoing literature on effects of underground coal mining on hydrologic systems and methods of mitigation; review of mining permits and complaint investigations on file at DMLR; review of court case decisions involving mining effects on groundwater and surface water; review of regulatory documents from other states active in Iongwall mining and the Federal Office of Surface Mining (OSM); and interviews with coal company personnel, DMLR and OSM officials, researchers, and regulatory officials in other states.

Review of both DMLR complaint investigations and published reports of numerous hydrologic investigations indicate that longwall mining is likely to alter the hydrologic regime in the vicinity of the mine. The knowledge base for regulation of hydrologic impacts has been inadequate but is being improved in Virginia. Both DMLR and some coal companies recognize the need for more and better data, and are taking steps to develop the requisite data and models. Regulatory personnel in Ohio, Pennsylvania, West Virginia, and Kentucky have expressed recognition of similar data deficiencies in their states. At least one state, Ohio, has dealt with the problem of water rights by enacting legislation that assigns liability for replacing damaged water supplies to the mining companies. West Virginia, through its regulatory program, also requires water replacement. Recommendations are offered that have as their main objective the reduction of uncertainty about the effects of longwall mining and about compensation of surface owners for damage to water supplies.