Development Law of water conducted fissure in overburden rock during the collaborative slicing of thickness-limiting and filling in extra-thick coal seams
In the early stage of coal development,due to the technical equipment issues,some mines limited their thick coal seam mining to a portion,leaving a large amount of idle high-quality coal resources.Based on the engineering background of the 20111 thick coal seam mining face in Yushuwan Coal Mine,we comprehensively used on-site measurement,UDEC numerical simulation,laboratory experiments,and theoretical analysis to study the development law of overlying rock water conducted fractures in the thick coal seam mining face of collaborative slicing mining with thickness limit and filling.Numerical simulation shows that,when the filling rate of the lower slicing filling mining reaches 70%or above,the development height of the water conducted zone is 177.4 m,and the lower slicing mining has no impact on the Quaternary Salawusu Formation aquifer;The physical model cross validation test of the lower slicing 70%filling mining shows that,in this condition,the development of overlying rock fractures slows down significantly,and the height of the development of the water conducted zone greatly declines to 179.7 m.The water conducted zone has not developed to the minimum waterproof protective layer,which indicates the extra-thick coal seam can be mined safely and efficiently under the Quaternary Salawusu Formation aquifer.