Dewatering and Depressurizing Effect of Roof Water in Deep Buried Coal Seam of Shaanxi and Inner Mongolia Contiguous Area

In order to achieve sufficient dewatering and depressurizing of roof water and safe mining of coal mining face, we research a kind of roof water dewatering and depressurizing consisted of "drain line drainage and floor drainage" and "the transfer of water warehouse and drainage ditch" based on the underground features of large coal mine and deep buried coal seam. The results show that total water yield for 44 drainage holes around open-off cut is stable at 150 m³/h, and total water yield keep stable when the number of drainage holes is changed. The water yield of drainage holes is primary dynamic water yield. Water pressure of T16-5 hole changes from 4.8 MPa to (0.9 to 1.0) MPa in central zone of roof water drainage. Other water pressure of observation hole is stable too, and roof aquifer has formed a stable cone of depression.