Study On The Risk Of Unknown Goaf Hydrops Of Shengli Mine And Its Detection Technology

Water disaster in goaf is one of the major disasters affecting mine safety production,especially the undetected goaf hydrops has great hidden dangers to the lower coal seam mining.To explore a set of detection and analysis method of water hazard risk assessment and its location and range of unexplained goaf,which will be of theoretical significance and practical application value to mine water control scheme.This paper takes the unidentified goaf hydrops area of Datong Coal Mine Group Linfen Hongda Shengli Coal Industry Co.,Ltd(Shengli Mine)as the research object,According to the theories of plate shell,key stratum and fracture mechanics,the mechanics analysis model of overburden and floor deformation and failure of coal seam mining in Shengli Mine was established,and combined with empiric formula method and numerical simulation method,the maximum probabilities of the coal seams of water fracture zone height and floor rupture zone depth were obtained.According to the distance between each coal seam and the nearest upper aquifer and the height of water flowing fractured zone,it is concluded that the goaf area of all the coal seams is filled with water,and there is possibility of water accumulation.Based on the main factors such as minimum distance of coal seam,maximum height of water flowing fractured zone,the maximum fracture zone of coal seam floor and the thickness of protective layer,the method and criteria for judging the risk of the lower coal seam mining in theupper coal seam goaf hydrops are put forward,and The risk of mining in 10#coal seam is determined by the water in mined-out area in 2G and 6O coal seams.The results show that the risk of hydrops seepage in the 2#coal seams belongs to the original rock permeability and the similar to the original rock permeability respectively.The danger of water seepage in the 6O coal seams are water inrush,which pose a serious threat to the 10#coal seam.Based on the investigation results such as location of mine wellhead,amount of coal produced,minimum uncovering coal distance and water in the bottom of mine,the method of predicting the location and range of the goaf and the water situation of early mined is established.And the position,range and water situation of the goaf area of the early-stage 6#are deduced,and the results of point,line and surface goaf of 6#are deduced respectively.According to the basic principle of transient electromagnetic method and the characteristics of ground geophysical results,an interpretation method of inferring the boundary of the goaf hydrops area is putforward.The method is used to deduce the goaf hydrops area of 6#coal seam.It is concluded that there are 3 goaf hydrops areas in 6o coal seam in the exploration area.Based on the basic principles and characteristics of the downhole transient electromagnetic method,a method of interpretation of the goaf based on coal seam intersection and apparent resistivity cross section is put forward,and adopting underground geophysical exploration and downhole drilling and small ore speculation results to carry out verification analysis.The results show that the range of goaf hydrops area measured by surface geophysical prospecting has high reliability,and the inferred result of unknown goaf area is of great reference value for further exploration.