The Study of Key Stratum Location and Characteristics on the Mining of Extremely Thick Coal Seam under Goaf

The basis of traditional ground pressure and strata control techniques is the key theory, wherein position stratum can easily be determined for coal seams with regular thickness without goaf. However, in case mining ultrathick underneath goaf, methods used calculation need to improved order account additional seam presence an upper This study analyzed failure height collapse characteristics overlying during excavation determining structure failed strata. results indicate that intercalation gradually evolve into a large “arch structure” small longwall mining, respectively. A mechanical model bearing interlayer was established according rock layer, which hinged block structure. maximum principal stress occurs when portion arch bears load. Consequently, movement evaluated throughout process method determine Xiegou mine. And agree engineering practice. are significant goaf mining.