China Safety Science Journal ›› 2026, Vol. 36 ›› Issue (S1): 67-74.doi: 10.16265/j.cnki.issn1003-3033.2026.S1.0011

• Safety Technology and Engineering • Previous Articles     Next Articles

AE and EMR characteristics of failure process of near vertical extra-thick coal seam

Yan Ruibing1(), Li Kang1, Jiang Xinjun1, Song Dazhao2, Du Taotao3   

  1. 1 CHN Energy Group Xinjiang Energy Chemical Co., Ltd., Urumqi Xinjiang 830027, China
    2 School of Resources and Safety Engineering, University of Science and Technology Beijing, ;Beijing 100083, China
    3 CCTEG Coal Mining Research Institute, Beijing 100013, China
  • Received:2026-02-05 Revised:2026-05-10 Online:2026-06-30 Published:2026-12-30

Abstract:

To address the problems that rock bursts in near vertical extra-thick coal seams are dominated by side heave and that existing acoustic-electromagnetic precursor criteria are mostly derived from near-horizontal or gently inclined coal seams with insufficient applicability, with the near vertical extra-thick coal seam of Wudong Coal Mine (dip angle 87°, average thickness 48.87 m) as the research object, synchronous uniaxial compression experiments combining AE and EMR were conducted on coal and rock samples, together with field multi-parameter monitoring of geoacoustic (GA), microseismic (MS), and EMR signals. Comparisons were also made with other typical coal seams at different dip angles. The results show that at the laboratory scale, AE-EMR amplitudes are positively correlated with stress, and the signal concentration of rock samples is higher than that of coal samples. Before the rock burst occurrence, the hourly GA energy and pulse count exhibit an M-shaped double-peak evolution, with the peak energy reaching the order of 103 J. The daily MS energy and frequency show a V-shaped precursor, with the peak energy reaching the order of 105 J, surging to 107 J on the day of rock burst. The EMR intensity presents an M-shaped distribution with increasing distance from the working face, with high-value zones located at 10-30 m and 70 m. The EMR intensity of the coal seam is 20%-35% higher than those of the roof and floor, consistent with the side heave characteristics. The MS frequency of the near vertical extra-thick coal seam is similar to those of other coal seams, whereas the V-shaped evolution pattern of MS energy is significantly distinct.

Key words: near vertical extra-thick coal seam, rock burst, acoustic emission (AE), microseism, electromagnetic radiation (EMR)

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