Feasibility analysis on upward mining in first mining area of Jike coal mine

Based on method of theory analysis and numerical simulation,feasibility analysis on upward mining on NO.M11 coal seam in the first mining area of Jike colliery in Yunnan province was studied.The results showed that the height of caving zone after mining is 8.47 meters,and height of fracture zone is 21.1~32.4 meters,the M9 coal seam is in the fracture zone of M11 coal seam after mining.Numerical simulation results indicated that the vertical stress in M9 coal seam is obviously reduced.The maximum height of fracture zone is 26 meters.And the relief effect is significant.It is feasible to make M11 coal seam as the operation layer for M9 coal seam.