Determination of Reasonable Offsets of Different Mining Process Combined Mining in Very Contiguous Seams

The distance of 9^# and 10^# coal seam in Shanxi Lingshi a mine is only 2.3 m, so it took combined mining method of high-grade conventional mining in 9^# coal seam, fully mechanized mining in 10^# coal seam. Based on the experience of other mines, the offset of begin recovery was about 15 meters, but two face pressure was always very great, the monomer pillar in 9# coal face had several pressure burst phenomenon, and the 10^# coal face had serious overall coal wall spalling. In order to reduce the pressure of working face, by theoretical analysis and field ground pressure observation, reasonable offsets of very contiguous seams combined mining in different mining process was determined, it achieved a safe and efficient combined mining.