Rock Mechanics for Industry, 37th U.S. Rock Mechanics Symposium, Vail, Colorado, 6–9 June 1999
Authors: R. R. Goodrich (AAI), W. K. Sorensen (Canyon Fuel Company), J. F. T. Agapito (AAI), and J. Black (Canyon Fuel Company)
Canyon Fuel Company operates the SUFCO coal mine located in the southern Wasatch Plateau Coal Field approximately 48 km (30 miles) east of Salina, Utah, USA. The mine produces coal from the Upper Hiawatha Seam of the Mesa Verde Group (Cretaceous) strata. Annual subsidence monitoring, mostly by aerial photogrammetric methods, has been conducted for the last 22 years. In 1998, detailed survey measurements of vertical and horizontal displacements over a longwall panel were conducted in order to better understand the response of the 61-m-thick (200-ft-thick) Castlegate Sandstone and to develop a failure criteria for naturally occurring rock deformations. Measurements indicate magnitudes and directions of transient and permanent deformation over the panels and gateroads as a result of longwall panel retreat. Vertical subsidence magnitude ranges up to approximately 1.62 m (5.3 ft). Magnitudes of horizontal movement measured over the panel have been up to 0.19 m (0.62 ft).