Correlations between acoustic and electromagnetic emissions and stress drop induced by burst-prone coal and rock fracture

Abstract Rockburst is a global problem in underground mining industry, threatening mining safety. Acoustic emission (AE) and electromagnetic emission (EME) are nondestructive and real-time geophysical monitoring methods with great significance for the accurate monitoring and early warning of rockburst hazard. To further evaluate the correlations between AE, EME, and stress drop quantitatively and provide an experimental basis for the in-site monitoring of rockburst hazard, an AE, EME, and load synchronous test system was established and used to obtain the full-waveform data of AE, EME, and load in the failure process of burst-prone coal and rock samples under uniaxial compression. The correlations between AE, EME, and stress drop and the spectral characteristics of AE and EME were studied. The results show that the number of AE events is greater than that of EME events. EME is generally accompanied by the stress drop and high-intensity AE and has better correlation with stress drop than AE. Rock samples have greater correlations among AE, EME, and stress drop than coal samples. For rock samples, the correlation coefficients between AE and stress drop, EME and stress drop, and AE and EME are 0.782, 0.889, and 0.697, respectively, while for coal samples, they are 0.529, 0.889, and 0.538, respectively. The frequency spectra of AE and EME have a high correlation, and they have the same low-frequency components of 1–17 kHz, which can be used as the frequency band of local monitoring in working face scale.