## 2 Engineering Background  
### Mining Geological Conditions  
The mine is located in the northwest part of the Binchang mining area in Shanxi Province, with a depth of nearly one kilometer. It primarily extracts coal from the 4# coal seam, the dip angle of the 4# coal seam is 2\({}^{\circ}\)-11\({}^{\circ}\), the average dip angle is 6.5\({}^{\circ}\), and the 4# coal seam has strong bursting liability. The second panel is positioned to the east of the west-wing main roadway. The length on strike is approximately 1050-1450 m, the inclined width is about 900 m, and the area is about 1.35 km\({}^{2}\). The thickness of the 4# coal seam in the second panel is 0.8-15.7 m, with an average of 10.5 m, and the buried depth is 850 m to 1000 m. Five working faces are arranged in the second panel, each separated by small coal pillars measuring 5.0-7.0 m, and all adopting the fully mechanized top coal cavity method. Among them, the mining height of LW205 is 3.5 m and the coal cavity height is 5.5 m, which ends in September 2021. The third panel is arranged as a small-panel layout, situated to the northwest of the second panel. There is a panel isolation coal pillar with a width of 200 m between the second and third panels. The inclined width of the third panel is approximately 550 m. The layout of the second and third panels is illustrated in Figure 1.  
According to the drilling holes 31-2, 27-2, and 30-3 near the second and third panels (see Figure 1 for the borehole locations), combined with the theory of key strata, the medium-coarse sand strata in the middle and upper part of the Luohe formation are the main key strata, with a thickness of 184-400 m and a distance of 113-294 m from the 4# coal seam. In the second panel, the thickness of the main key strata on the side of the 201 goaf is larger, while that on the side of working face 205 (LW205) is smaller. Additionally, based on in situ logging data, the water-rich aquifer is entirely present in the Luohe formation, with the middle section of the Luohe formation containing 75% of the water-rich aquifer. This aquifer has a thickness ranging from 90 to 110 m, its average porosity is 15.44%, its average unit water inflow is 1.305 to 2.248 L/(s-m), and the permeability coefficient of it is 0.06-1.552 m/d. It is recharged by the lateral runoff of groundwater, so it is difficult to drain [27]. The stratigraphic relationship between the water-rich aquifer and the main key strata is shown in Figure 2.  
Figure 1: Schematic diagram of the working faces layout of the 2 nd and 3 rd panels. Analysis of the Spatial Distribution Characteristics of Large-Energy Microseismic Events and Water Intrusion Situations  
The second panel consists of five working faces, and the varying maximum water inflows of different working faces at the initial mining stage is illustrated in Figure 3. The maximum value of water inflow in the initial mining stage of different working faces has opposite characteristics with the corresponding mining distance. When mining to working face 202, the maximum value of water inflow increases slightly. As mining progresses to the working faces 203 and 204, it is basically stable, which is around 600-700 m\({}^{3}\)/h. However, when mining reaches working face 205 (LW205), it sharply rises to 1500 m\({}^{3}\)/h. In the initial mining stage of the working faces 202, 203, and 204, the water-conducting fractures develops to the lower part of the Luohe formation. At this point, the maximum water inflow in the initial mining stage of the three working faces is basically stable. However, in the mining of working face 205 (LW205), the water-conducting fractures from the working face extend to the lower part of the main key strata, which is in the middle part of the Luohe formation, communicating with a highly water-bearing layer. This leads to a sudden increase in the maximum water inflow in the initial mining stage of working face 205 (LW205).