Abstract
A rock burst accident occurred on coalface 13230 of the Gengcun Coal Mine in Henan Province. Through a field investigation, theoretical analysis, and microseismic monitoring, we studied how the rock burst, which was caused by overall seam floor slip and instability, occurring under an ultrathick conglomerate. Because the overlying ultrathick conglomerate in the mined-out zone close to coalface 13230 had been inadequately mined, the leading section of the coalface was under a high level of stress. Combined with the tectonic stresses from the F16 faultage and the soft floor structure, these factors caused the floor of this coalface to trigger the overall slip-type rock burst. In this paper, an estimation model of the ultimate bearing capacity of a seam floor under an ultrathick conglomerate and the advancing abutment pressure on the coalface is presented. This model is used to show that the ultimate bearing capacity of the seam floor on coalface 13230 is 26.3 MPa, and the abutment pressure is far more than the floor bearing capacity. We also present pressure relief and reinforced supporting measures, which can effectively prevent floor slip-type rock bursts from occurring. The results of this study provide a reference for the prevention and control of floor slip-type rock bursts in coal mining under an ultrathick conglomerate.
Highlights
A rock burst is the sudden release of elastic energy accumulated by a coal and rock mass. Such events have become a common type of dynamic disaster that seriously threatens mine production safety [1,2,3,4,5,6,7,8]. e average thickness of the coal seam in the Yima Coal Field in Henan is 10 m. e roof of this seam is made of an ultrathick conglomerate. e top coal mining approach used in this area leaves clear traces of rock bursts
Further study is required. is paper is based on the rock burst accident that occurred on the fully mechanized coalface 13230 in the east-3 mining zone of coal seam 2-3 in the Gengcun Coal Mine, which includes the Yima Coal Field. rough a microseismic monitoring, a theoretical analysis, and a field investigation, this paper analyses the formation mechanism of floor rock bursts when an ultrathick conglomerate is mined, identifies the formation mechanism of rock bursts in the Yima Coal Field, and proposes specific control measures for the prevention and control of rock bursts in similar conditions
According to the geostress test results, the stress of the primary rock is slightly higher than the medium level, and the four test points are all far away from the mined-out zone, which can reflect the stress of the primary rock. e three (75%) test points are dominated by vertical stress, and one (25%) test point has tectonic stress. erefore, coalface 13230 and the area near the coal pillar between the mines are subject to both vertical stress and horizontal tectonic stress, creating stress conditions for the occurrence of rock bursts
Summary
A rock burst is the sudden release of elastic energy accumulated by a coal and rock mass. Based on the coupling hypothesis of static and dynamic stresses, Wu et al [11] studied the formation mechanism of rock bursts. Pan [22] et al studied the formation mechanism of rock bursts when there are two soft coal seams. Yu et al [23] studied the formation mechanism of rock bursts when there is an ultrathick conglomerate. Few studies have considered the formation mechanism of rock bursts on the seam floor under an ultrathick roof conglomerate. Is paper is based on the rock burst accident that occurred on the fully mechanized coalface 13230 in the east-3 mining zone of coal seam 2-3 in the Gengcun Coal Mine, which includes the Yima Coal Field. Further study is required. is paper is based on the rock burst accident that occurred on the fully mechanized coalface 13230 in the east-3 mining zone of coal seam 2-3 in the Gengcun Coal Mine, which includes the Yima Coal Field. rough a microseismic monitoring, a theoretical analysis, and a field investigation, this paper analyses the formation mechanism of floor rock bursts when an ultrathick conglomerate is mined, identifies the formation mechanism of rock bursts in the Yima Coal Field, and proposes specific control measures for the prevention and control of rock bursts in similar conditions
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
