# Applications of Microseismic Monitoring Technique in Coal Mines: A State-of-the-Art Review
## 4 Applications of Microseismic Monitoring in Coal Mine
### Water Intush  
Chinese coal mines face the most complicated hydrogeological conditions worldwide, and nearly 900 coal mines have suffered the serious threat of water intush [19]. Water intush is a catastrophic disaster frequently encountered in Chinese coal mines, caused by high-intensity mining in complex hydrogeological scenarios. As the mining operation goes deeper, the increasing water pressure and ground pressure result in a sharp increase in the probability of water intush. The water-conducting channel is a necessary condition for water intush in deep coal mines, which involves the evolution of coal/rock micro-fractures under a high-stress regime and water pressure [59]. Figure 9 illustrates a typical water intush disaster from various water source locations, and the water-conducting channel connecting the excavation face and the water source is one of the key factors inducing water intush. Therefore, identification of the micro-fracture precursor is essential to study the generation of the water-conducting channel and to warn miners of water intush in coal mines. \begin{table}
\begin{tabular}{c c c} \hline
**Occurrence Time** & **Location** & **Description of the Rockburst** \\ \hline
19 June 2007 & 25080 working face of Yuejin coal mine & destructed a nearly 300-m-long roadway. \\
5 June 2008 & 21201 working face of Qianqiu coal mine & killed 13 miners and damaged a 565-m-long roadway \\
1 March 2011 & 25110 working face of Yuejin coal mine & damaged a 200-m-long roadway \\
15 October 2012 & Xing’an coal mine & damaged a 104-m-long section of the roadway \\
15 March 2013 & Junde coal mine & trapped 25 miners, and destructed the tailgate and headgate \\
26 July 2015 & 3302 working face of Xingcun coal mine & damaged a 200-m-long roadway \\
22 December 2015 & 13230 working face of Genguin coal mine & damaged more than 160-m-long roadway \\
15 September 2016 & Open-off cut of Junde coal mine & trapped and sulfocated five miners \\
20 October 2018 & Longyun Coal Industry Co., Ltd., Yuzhou, China & killed 21 miners \\ \hline \end{tabular}
\end{table} 
Table 3: Some intense rockburst cases in Chinese coal mines [86; 100]. Microseismic monitoring is capable of capturing and characterizing micro-fractures in coal/rock mass, which has been extensively utilized to study the generation process of water inrush during coal mining in recent years. [PERSON] et al. [107] estimated the failure depth of an inclined floor above a confined aquifer using the planar and vertical distribution of microseismic events at the Taoyuan coal mine and successfully identified the floor near two mining roadways as dangerous areas regarding water inrush. [PERSON] et al. [77] used the contour of microseismic event density to identify the high-risk area of water inrush in the Dongjiahe coal mine; furthermore, they inverted the focal mechanism of microseismicities in the potential water inrush region by executing the moment tensor analysis, which revealed the mixed failure mechanism of the floor ruptures. [PERSON] et al. [59] identified the location and generation of water-conducting channels in the Dongjiahe coal mine by utilizing the contour of microseismic energy density, and the variation in microseismic parameters, e.g., the energy release, seismic potency, and cumulative apparent volume, were analyzed to study the precursors for the water flow channels. Furthermore, they established an early warning system for water inrush based on geophysical methods and a geological survey (Figure 10). [PERSON] et al. [108] used the improved theoretical model considering the confined aquifer and numerical modeling considering the coal/rock heterogeneity to investigate the stress regime variation and floor failure process; additionally, they estimated the floor failure depth using microseismic monitoring data. [PERSON] et al.