18E.100.020 Mine Hazard Areas.
A. General. Mine hazard areas are areas directly underlain by, adjacent to or abutting, or affected by old mine workings such as adits, tunnels, drifts, or airshafts that have the potential for subsidence.
B. Mine Hazard Area Indicators. Indicators of old mine workings underlying a site include:
1. Remnants of old mine workings or excavations.
2. Unusual depressions in the ground surface possibly related to plugged or bridged air shafts or adits, or collapse of underground working.
3. Spoil or waste piles from exploration tunneling or glory holes.
4. Any other abnormal topographic features that might indicate subsurface boring or tunneling.
C. Potential Mine Hazard Areas.
1. Sections of land, identified on the Washington Department of Natural Resources, Division of Geology and Earth Resources, Washington State Coal Mine Map Collection (Open File Report 94-7, June 1994), that contain coal mine workings.
2. Sections of land, identified on the Map of Mashell Coal and Coke Company Figure 1, Ashford Vicinity Map, that contain coal mine workings.