Development of Dynamic Subsidence Over Longwall Panels in the Northern Appalachian Coal Region.
Adamek-V; Jeran-PW; Trevits-MA
Proceeds 33rd U S Symp on Rock Mech Santa Fe New Mexico, 6/8-10/92 WVU PP 243-251 :243-251
It is a common perception that an increased rate of longwall face advance will result in a flatter dynamic subsidence trough above the panel, thus diminishing the magnitude of surface deformations: inclination, curvature, and horizontal strain. However, a thorough analysis of centerline field data from 14 Bureau longwall panel studies (where the average rate of face advance ranged from 6.3 To 44.6 Ft/day) revealed the only effect of the differing rates of face advance on dynamic subsidence was the duration of its development. There was no effect on either the magnitude or the distribution of the surface deformations. Since the rate of face advance does not play a role in dynamic subsidence development, it has been determined that the prediction of dynamic subsidence can be approached using a methodology developed for static subsidence prediction. The position of the face at a given time for dynamic prediction plays the same role as the edge of the panel for static prediction. An alternate method, based upon the distribution of the percentage of the maximum subsidence of any point versus the ratio of the distance from the face to overburden thickness, is also proposed. Both prediction methods produce acceptable results.
Proceeds 33rd U.S. Symp. on Rock Mech. (Santa Fe, New Mexico, 6/8-10/92). WVU, PP. 243-251