Enhancing Microseismic Monitoring Through Controlled Blasting: Waveform Analysis, Location, and Magnitude Determination in Dongtan Coal Mine, China

Abstract As coal reserves are exploited in deeper geological strata, the associated high stress and complex geological conditions lead to an increase in microseismic events. These events serve as precursor signatures for dynamic failure mechanisms—particularly stress-threshold-governed rock bursts—thereby introducing latent geotechnical risks to mining operations. Consequently, the deployment of microseismic monitoring systems in coal mines becomes critical. However, many of these systems in Chinese coal mines suffer from significant drawbacks due to maintenance and calibration deficiencies, inaccurate event location, and considerable errors in magnitude estimation. To address these issues and enhance the systems’ reliability and accuracy, we initiated controlled blasting experiments at the 6306 working face of the Dongtan Coal Mine. Here, we strategically deployed seismometers both at surface and underground locations near the blasting sites to capture the resultant seismic waves. Our analysis revealed substantial differences in waveform characteristics observed at surface versus underground stations. Specifically, waveforms recorded at surface stations demonstrate P-wave dominance near the source with high-amplitude, pulse-like signals, transitioning to prominent surface waves as the distance increases. In contrast, underground stations predominantly captured high-frequency P waves with shorter durations and more complex waveforms due to multipath propagation and source location discrepancies. The relocation results demonstrate that the double-difference location method is effective in achieving relatively high-accuracy event locations when utilizing both surface and underground data. Furthermore, we established a precise calibration function applicable to the Dongtan Coal Mine and determined the local magnitudes of eight blasting events. On the basis of these results, an empirical relationship between local magnitude and weights of explosives was preliminarily derived. These findings can help enhance the reliability of microseismic monitoring systems in coal mines, thereby contributing to safer mining operations.