Coal Mine Subsidence near Sheridan, Wyoming. Subsidence depressions, pits, and cracks above the south part of the abandoned room-and-pillar Acme Mine. The mine was operated from the early 1900's to 1943. The location and geometry of subsidence depressions and pits correspond to mining areas and to individual mine openings. Subsidence depressions containing pits and bounded by tension cracks. Pits of markedly different ages are present, ranging from bowl-like depressions blanketed by green grass, many years or decades old, to small pits with vertical or overhanging walls, only a few months or years old. Subsidence depressions, pits, and cracks occur sporadically in the road in the left foreground and present problems to stock and vehicle travel. May 1976. Figure 7-B, U.S. Geological Survey Professional Paper 1164.
Digital File:dcr00011