Spatial and temporal microseismic evolution before rock burst in steeply dipping thick coal seams under alternating mining of adjacent coal seams

0546789 - ÚGN 2022 RIV DE eng J - Journal Article
Wu, Z. - Pan, P.-Z. - Koníček, Petr - Zhao, S. - Chen, J. - Liu, X.
Spatial and temporal microseismic evolution before rock burst in steeply dipping thick coal seams under alternating mining of adjacent coal seams.
Arabian Journal of Geosciences. Roč. 14, č. 20 (2021), č. článku 2097. ISSN 1866-7511. E-ISSN 1866-7538
Institutional support: RVO:68145535
Keywords : rock burst * steeply dipping thick coal seam * adjacent coal seams * microseismic * precursor characteristics
OECD category: Mining and mineral processing
Impact factor: 1.827, year: 2020
Method of publishing: Limited access
https://link.springer.com/article/10.1007%2Fs12517-021-08439-8

Due to the complex geological conditions and special mining approach of the steeply dipping thick coal seam in the south mining area of the Wudong coal mine, dynamic hazards are frequently encountered during horizontal section top-coal caving. Identification of rock burst precursor information can help effectively avoid its occurrence, decrease unnecessary loss, and ensure personal safety of underground workers. The B3+6 coal seam working face of the south mining area of the Wudong coal mine at +475 m level and +450 m level is monitored using a microseismic (MS) monitoring system. The spatial and temporal evolution patterns of MS parameters before rock burst occurrence are investigated and compared with the evolution pattern of precursor characteristics in the gently inclined coal seam. The results show the following data: (1) The daily MS total energy and event count exhibited a sudden decrease and abnormal fluctuation before rock burst occurrence in the steeply dipping thick coal seam of the south mining area of the Wudong coal mine, which can be employed as an effective precursor signal for rock burst early warning. (2) The MS sources were mainly concentrated around the rock pillar, which created a high static stress condition for the occurrence of rock burst and served as the force source of rock burst. The rock pillar was also the main cause of rock burst in the B3+6 coal seam. (3) The MS event aggregation index is defined, which shows sudden fall and rise variation and reaches an extremely low value immediately before the rock burst occurrence. This phenomenon can be considered as a rock burst precursor in the steeply dipping thick coal seam of the south mining area of the Wudong coal mine. (4) For the steeply dipping thick coal seam, the sharp rise and fall of the daily MS average energy does not necessarily mean rock burst occurrence, while the abnormal fluctuation of the daily MS average energy is very likely the precursor of rock burst occurrence. (5) More attention should be paid to the floor (rock pillar) rather than the roof in the study of rock burst in the steeply dipping thick coal seam under similar conditions.
Permanent Link: http://hdl.handle.net/11104/0323170