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

West Virginia Geological and Economic Survey personnel are creating a GIS-based inventory of coal in West Virginia. Final GIS coverages created 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. Geologists use combinations of modeling and GIS software to create the coverages. First, all geologic control data (core logs, measured sections, mine map data, analyses, etc.) are entered into a relational database, verified and correlated. Initial structural contour maps are created with modeling software then revised by hand to properly reflect relationships with over- and underlying coal beds. Final structural contour lines are scanned, auto-vectorized, and attributed. Outcrop lines are generated automatically by GIS operations using grid coverages created from the structural contours and digital topographic lines (hypsography). Variation in net coal thickness, total bed thickness, and percent parting are represented with 30-meter grid coverages, created using an inverse distance weighted algorithm. Surface mined areas are digitized on screen from georeferenced, tiled, raster images of the 7.5-minute topographic maps. Newer surface mining is likewise digitized from Digital Orthophoto Quarter Quadrangles (DOQQs) utilizing 3-D capabilities of image processing software. Underground and auger mined areas are compiled by scanning mine maps and georeferencing them to the raster topographic maps. The outlines of the auger and underground mines are digitized on-screen. Attributes assigned to the polygons include type of mining, mine name, company name, date and others. Users have powerful, flexible, analytical resources in these GIS-based coal geology maps. A principal use is input into a valuation model by the Department of Tax and Revenue for mineral lands taxation. Other uses include coal resource and reserve estimates, coal geology research, investigation of abandoned mine lands, permitting, regional exploration, planning and development, and others.