Mapping of hydrogeology of underground mines in the Upper Freeport coal seam, northern Appalachian Basin, West Virginia-Pennsylvania-Maryland.

摘要

The mining hydrogeology of the Upper Freeport underground coal mining district, northern WV and western MD, was compiled onto a number of 1:24,000 scale quadrangles. Available underground mine maps were georeferenced and outlines of mine workings digitized using GIS techniques. Geologic information (coal outcrop location and structure contour elevations) was compiled using geostatistical methods. The mine maps were used in conjunction with projected mine discharges to delineate pool locations and flooding patterns. The relatively small number of flooded mines was mapped under the assumption that discharge location and elevation controlled the extent of the flooded mine area.;These mapping and geostatistical techniques may be used to integrate mining, coal bed structure and outcrop, and mine pool datasets. The accuracy of results is spatially variable and depends on the age and quality of original mine maps, as well as the degree to which these may be accurately georeferenced. A key feature of mining maps in this study area is that many old maps are of poor quality, and in some areas few maps of any kind are available. Areas with numerous recent mine maps are more likely to produce higher quality mapping of mines, structure/outcrop, and flooded areas.;Underground mined areas are focused in large synclines, and the mine pools that do occur are found along their down-dip limbs. The majority of mines in the study area, however, are abandoned, above regional drainage and largely free-draining. Major rivers paralleling synclinal axes are the focus for impacted tributaries transporting AMD in a down-dip direction. Thus the pattern of AMD discharges and stream water contamination is controlled by regional geologic structure, location of streams parallel with synclinal axes, and location of underground mines surrounding synclinal axes.