## 3 Results and Discussion
### Dynamic Distribution of Bled Water Seepage  
Based on the overburden saturation results monitored by seepage experiments with three types of initial saturation and the experimental transparent box observation results, the two-dimensional saturation distribution contour diagram of the seepage strike profile of  
Figure 6: Relationship between horizontal and vertical seepage distance and time at different initial saturation. \(S_{\mathrm{r1}}=73\%\); \(S_{\mathrm{r2}}=51\); \(S_{\mathrm{r3}}=29\%\); V indicates vertical direction; H indicates horizontal direction.  
the IOGI was drawn. The final saturation distribution contour diagrams of the slurry-bled water seepage in the overburden at 29%, 51%, and 73% of the initial saturation are shown in Figure 7a-c. The results show that the higher the initial saturation of the overburden, the larger the range of complete saturation of the overburden at the end of grouting and the closer its boundary to the working face. At an initial saturation of 73%, the adjacent overburden above the working face is saturated.  
From the above analysis, when the overburden is saturated, the bled water seeps downward. It can be inferred that if the overburden above the working face reaches full saturation, the bled water continues to seep downward, and water leakage occurs at the location of the working face. Based on the distribution contour of seepage saturation of slurry-bled water under three initial saturation conditions (Figure 7), it can be determined that under the conditions of initial saturation of 29% and 51%, the adjacent overburden above the working face (the bottom of the overburden) is not saturated, and no water leakage is observed at the working face (Figure 7b). At an initial saturation of 73%, the adjacent overburden above the working face was completely saturated, and water leakage occurred at the working face (Figure 7c).  
At an initial saturation of 73% (Figure 8a), it was found that measurement points #9 and #12 above the working face were saturated, and the corresponding water leakage measurement points S11, S12, S14, and S15 of the working face were detected (Figure 9). Among them, point S11 is located directly below the saturation measurement point of #9; S12 is close to #9; S14 is directly below #12; S15 is close to #12, and the other measuring points (#3, #6) are not saturated, and no water leaked (Figure 8b). Therefore, water only leaks when the porosity saturation of the adjacent overburden above the working face is saturated.  
Figure 7: The strike profile contour diagram of the saturation distribution of group seepage: (**a**) \(S_{\rm r}=29\%\); (**b**) \(S_{\rm r}=51\%\); and (**c**) \(S_{\rm r}=73\%\). Here, \(S_{\rm r}\) is the initial saturation; #1–#12 indicate moisture content sensor measurement points; the arrows represent grouting.  
Based on the above analysis, the higher the initial saturation, the larger the seepage range of bled water, the closer its boundary to the working face, and the more likely the water leakage is to occur at the working face. Therefore, initial saturation is the key factor affecting the seepage of the IOGI into overburden and water leakage in the working face.