Study On Effective Protecting Zone Of Protecting Stratum Mining

Protecting stratum mining is the most effective and economic regional measure to prevent coal and gas burst. But effective protecting zone of protected stratum is difficult to be confirmed and few studies on that have been done. So, for optimizing protecting stratum and making outburst coal get effective protection the authors study effective protecting zone and its affecting factor taking protecting stratum mining of Yeqing working face of Xuecun mine for example,. The study results show that the protecting zone along slope direction is related to geological factors. The upper border is located in the normal line position of supply gate commonly, and the underside border is located in 30m outside of normal line ofsupply gate. In general, the destroyed and affected zones respectively situate the position of 70m-80m and 100m-120m outside vertical projection line. After the Yeqing protecting stratum is mined, the air permeability of Damei coal increases. Discharging gas of protecting stratum by adopting high and low drilling can not only improve gas suctions rate, but also enlarge effective protecting zones. By mining protecting stratum and gas drainage, the hazard of coal and gas burst of protecting stratum can be eliminated, and safety production of working face and effective and safe mining of coal and gas can be achieved.