# Risk Identification Method and Application of Roof Water Inrush Under Multi-Working Face Mining
## 5 Field Monitoring Verification  
Microseismic monitoring was used on the 120501 working face to assess the development height of the water-conducting fracture zone in the roof following the extraction of the No. 5 coal seam. The development height was determined based on the daily maximum values recorded by the microseismic monitoring system. From the official operation of the monitoring system on 2 December 2023 to the complete destruction of the measurement line on 30 May 2024, the effective monitoring period lasted approximately six months. Microseismic events with a magnitude of 0.2 or higher were considered in the analysis. The comprehensive analysis revealed that the maximum development height of the water-conducting fracture zone in the 120501 working face was 64 m, which aligns well with the predictions derived from this method, thereby validating the effectiveness of the proposed approach. The daily maximum development height of the roof microseismic events during the mining of the 120501 working face is illustrated in Figure 13. This figure specifically presents the maximum height of the hypocenters associated with these roof microseismic events.  
Figure 13: Daily maximum development height of roof microseismic events (2 December 2023–30 May 2024).  
Throughout the mining period, the 120501 working face did not experience any roof water inrush incidents. Despite the repeated disturbances caused by mining activities at the 120501 working face, the 110504 working face did not encounter any delayed roof water inrush incidents either, which is consistent with the findings of the numerical simulations.  
The surface subsidence at different stages of the 110504 working face was analyzed using monitoring points, as illustrated in Figures 14 and 15.  
From the figures, it can be observed that as the 110504 working face continues to advance, the point of maximum surface subsidence progressively shifts towards the center of the working face, eventually stabilizing and forming a funnel-shaped subsidence profile. Following the extraction of the 120501 working face, a secondary subsidence event occurred in the 110504 working face. As shown in Figure 16, the overall pattern of this secondary subsidence remains relatively unchanged, with no abrupt or sudden sinking observed. Analysis of the roof height data for both working faces reveals that the roof height of the 120501 working face is lower than that of the 110504 working face, and no delayed water inrush phenomena were detected in the 110504 working face. This suggests that repeated  
Figure 14: Contour map of ground subsidence at 225 m advancement of the 110504 working face.  
Figure 15: Contour map of ground subsidence during the stabilized subsidence stage of the 110504 working face (5 November 2023).  
mining activities did not lead to a significant increase in the roof height of either the 110504 or 120501 working faces. Given that the 120501 working face is adjacent to the 110504 working face and shares similar overlying rock strata, it can be inferred by analogy that the risk of water inrush induced by an abnormal increase in roof height due to repeated mining activities is minimal.