APPLICATION OF GEOGRAPHIC INFORMATION SYSTEM (GIS)-BASED COAL GEOLOGY MAPS IN WEST VIRGINIA

West Virginia Geological and Economic Survey (WVGES) personnel are creating a GIS-based inventory of coal in West Virginia. Final GIS coverages for each coal bed include structural contours and outcrops; net coal, total bed height, and percent partings isopachs; mined areas; coal bed discontinuities; thickness and elevation control points; coal quality variation; and others. GIS and the GIS-based coal geology maps are powerful analytical tools to address many issues facing coal-producing areas such as taxation, coal resource and reserve estimates, land-use conflicts, abandoned mine lands, permitting, post-mine land use, planning and development, and others. The coal bed GIS coverages can be manipulated to create new products for focused analyses.

Combining the overburden grid coverage created for each coal bed with the underground mined polygons produces subsidence risk maps. Data on site-specific occurrence of subsidence could be added to fine-tune risk analysis. Grid coverages depicting the variation in net coal thickness, total bed thickness, and percent partings are used to estimate in-place tonnage. The estimates can readily be categorized by polygons of various size from the entire state to an individual land parcel. The estimates can be further subdivided by confidence level, thickness categories, quality parameters, or other constraints. Coal thickness grid coverages can also be combined with overburden grids to calculate yards-of-overburden/tons-of-coal ratio coverages. Such maps can aid in delineating potential mountaintop surface mining sites. Structural contour coverages, coal outcrop lines, and mining can be used to identify potential mine water blowout sites or monitor mine pool levels. GIS also gives users the ability to combine WVGES coal coverages with datasets they have created. For example, comparison of dam and impoundment locations and elevations with coal mined areas and structural contours could identify areas of potential impoundment or dam failure from mine subsidence. This example indicates the utility of these coverages in permit review for proposed mining operations or facilities.