Microseismic signals of double-layer hard and thick igneous strata separation and fracturing

In order to analyze the microseismic (MS) effects of hard and thick igneous strata separation and fracturing and the corresponding evaluation index of fracturing intensity, the temporal-spatial evolution of the MS sources generated by igneous strata fracturing in the 10416 working face of the Yangliu coal mine (YCM) was dynamically recurred, and the waveform and frequency-spectrum distribution characteristics of primary and igneous strata fracturing were clearly investigated, respectively. In addition, the relationship between the MS dominant frequency, the energy ratio in low-frequency band and the intensity of igneous strata fracturing was revealed, and the energy ratio of MS event in low-frequency band can be verified as an effective index for evaluating roof fracturing intensity. The work may put forward a certain reference for early warning and evaluating hard and thick roof fracturing and the induced coal-rock dynamic disasters based on in-situ MS observation. (C) 2016 Elsevier B.V. All rights reserved.