Research on precursory patterns and mechanisms of microseism and electromagnetic radiation during the evolution...

To address the frequent occurrence of rock burst in deep mining at Yuejin Coal Mine and the inaccuracy of traditional single-index early warning, this study integrates electromagnetic radiation (EMR), microseismic (MS) monitoring, and on-site observations to systematically analyze the precursors and mechanisms of rock burst in the 25,110 working face. The results show that EMR signals exhibit three temporal patterns: rise-then-fall (71.4% of events), continuous fall, and continuous rise. Spatially, EMR intensity in the damage zone increases significantly 1-2 days before a rock burst, and bursts mainly occur in areas 0-50 m or beyond 200 m from the working face. MS signals follow a consistent rise-then-fall pattern: energy and frequency increase 4-9 days before the burst, peak 1-5 days later, then decline, with the burst occurring 2-3 days after the decline begins. Based on the energy response and perturbation effect of EMR signals, three precursory mechanisms are identified: "rising (falling)", "∧" shaped, and "N" shaped, corresponding to different failure stages of coal-rock under loading. These findings provide theoretical support for precise, multi-parameter early warning of rock burst in coal mines.