Slope instability below historic mine benches in the northern coalfields of West Virginia

Abstract

Anthropogenic reshaping of landscapes can increase landslide activity. One example of heavily modified, landslide-prone landscapes is the Appalachian region, which hosts weak geologic strata, steep slopes, a humid climate, geologically recent river incision, and large-scale landscape modifications resulting from surface mining. Surface mining conducted before the Surface Mine Control and Reclamation Act (SMCRA) of 1977 did not require reclamation to approximate original contour, so remnant highwalls and mine benches are common throughout Appalachia. This study investigated the occurrence of slope instability and failure beneath pre-law mine benches in the northern coalfields of West Virginia. Mine bench features were manually digitized based on interpretation of high-spatial-resolution digital terrain data and aerial orthophotography, and ancillary geospatial data (i.e., mine permit boundary and disturbance extent data sets). A subset of mine bench features, stratified by coal seam, was randomly selected for slope stability analysis. The lower margins of the randomly selected mine benches were differentiated into segments with and without evidence of slope failure or instability. Results suggest that local topographic slope and aspect were not strong determinants of slope instability beneath mine benches. However, the coal seam or unit that was mined was an important determining factor. The Pittsburgh seam, and to a lesser extent the Redstone seam, had a larger proportion of their lower margins showing evidence of slope failure than did other seams. This study highlights that local-scale geology controls the geomorphic response to human landscape modifications and suggests that proactive reclamation of surface coal mines might reduce slope-failure geohazards.

Citation

Ali, Muhammad; Maxwell, Aaron E.; Shobe, Charles M.; Farhadpour, Sarah. 2025. Slope instability below historic mine benches in the northern coalfields of West Virginia. Environmental and Engineering Geoscience. XXXI(4): 267-283.