Development characteristics of water-conducting fractured zone in deep coal seam based on microseismic monitoring

The development height of the water conducting fractured zone is one of the important technical parameters for mine water hazards prediction. In this paper, the combined well-surface microseismic monitoring technology was used to analyze the development characteristics of the water conducting fractured zone in working face 4103 in Wenjiapo coal mine. The results showed that for deep buried coal seams, the microseismic events occured in the advance mining face with advanced influence angle ranging from the minimum of 28° to the maximum of 35°. The stability of overburden decreased due to the faults. Thus, compared with normal bedrock, the overburden rock was easier to cause stress concentration and rock failure under the influence of coal mining. The distance between the microseismic event location and mining position increased affected by the fault, and the high density distribution area of the microseismic events shifted to the goaf, which aggravated the degree of overburden failure and increased the water conducting fractured zone height. In vertical direction, the high density area of microseismic events in the monitoring area of working face 4103 ranged from +400 m to +520 m. Combined with the number and the energy distribution characteristics of microseismic events, it could be concluded that the development height of caving zone in working face 4103 was 50 m, and the ratio of caving to mining was 13.16. The development height of water-conducting fractured zone was 117 m, and the ratio of fracturing to mining was 30.79. The results could provide an important basis for the analysis of water conducting fractured zone height of deep coal seam and the prevention of roof mine water disaster in Binchang mining area.