Coal Engineering ›› 2024, Vol. 56 ›› Issue (4): 67-72.doi: 10.11799/ce202404010

Previous Articles     Next Articles

Damage and oxidation characteristics of coal pillar in upper working face of contiguous coal seams

  

  • Received:2023-09-22 Revised:2024-02-24 Online:2023-04-20 Published:2024-12-09

Abstract:

In order to study the influence of short-distance coal seam mining on the damage and oxidation characteristics of coal pillars in the upper working face, taking the 74201 working face in Bailu Coal Mine as the research background, based on numerical simulation and experimental research, the influence of short-distance coal seam mining on the plastic regional distribution and oxidation characteristics of coal pillars in the upper working face was analyzed. FLAD3D simulation results show that with the advance of 4-2 coal seam, the failure and deformation characteristics of coal pillars in the upper coal seam are approximately divided into three stages: the coal pillars are complete; The coal pillar is deformed and damaged, but it maintains basic continuity; The coal pillar is sheared and broken in a large range. The temperature programmed experiment shows that the critical temperature points of CO and C2H4 are advanced by 10~20℃ in the secondary oxidation process of coal pillars that have been oxidized to a certain extent, and the oxygen consumption rate increases by 2573.1×10-11 mol/(cm-3 s) at the highest. C2H2 was not detected in the intact coal pillar, C2H2 gas was detected in the 4-1 fractured coal pillar and 4-1 fractured coal pillar at 250℃ and 240℃ respectively, which proved that it entered the stage of violent oxidation. It was concluded that the coal pillar crushing process promoted the secondary oxidation process of coal to some extent, and the fractured coal pillar was more prone to spontaneous combustion than the intact coal pillar. This study draws the conclusion that the spontaneous combustion risk of broken and unstable coal pillars in upper coal seam increases with the mining in lower coal seam.

CLC Number: