Abstract
The detailed geology in portions of five underground coal mines in southern West Virginia was mapped, tabulated, and analyzed with respect to roof conditions. Cross sections and maps were constructed to illustrate roof rock types and their distribution and structure. Numerous data were compiled on coal cleat orientation. The following five geologic features were identified as the chief causative factors in hazardous mine roof: roof consisting of underclay (seatearth), presence of small sandstone-filled channels or tilted slump blocks, undulating sandstone cutting across shale roof rock, interlaminated shale and sandstone (stackrock), and roof consisting of conglomerate. The chief factors contributing to good roof conditions were as follows: absence of slickensides, hard sandstone roof rock >10 feet thick, and upward gradation of roof rock from shale to sandstone.
