To evaluate the disturbance of the overlying aquifer due to high-intensity coal mining in the deep part of the Yushen mine area and to analyze the failure patterns of the overburden, the characteristics of overburden damage at the Dahaize coal mine were studied by using theoretical analysis, numerical simulation, and on-site measurements. Based on the method for predicting the height of the water-conducting fracture zone according to the position of the key stratum, it was predicted that the height of the water-conducting fracture zones near the observation holes of the first mining face LD1 and LD2 of the Dahai coal mine would be 93 m and 83.7 m, respectively. Using universal distinct element code (UDEC) numerical simulation with triangular block division of the rock strata, the heights of the water-conducting fracture zones at the LD1 and LD2 boreholes were shown to be 94.5 m and 82 m, respectively. The actual measurements show that the height of the water-conducting fracture zones at the LD1 and LD2 boreholes are 86.41 m and 81.81 m, reaching the bottom of the thick and hard rock layer in the middle of the Zhiluo Formation. The results indicate that combining predictions of the height of the water-conducting fracture zone based on the theory of key strata with discrete element numerical simulations can effectively predict the height of overburden damage under conditions of high-intensity mining. Simulations show that there are significant differences in the subsidence characteristics above and below the thick and hard rock layer, with the lower part having a smaller angle of subsidence than the upper part. The angle of subsidence and breakage of the overburden increases with the increase in mining height. Influenced by the structure of the overburden, within the same working face, locations with lower mining heights may have higher water-conducting fracture zone compared to those with greater mining heights. When estimating the height of the water-conducting fracture zone in deep, high-intensity mining operations, full consideration should be given to the structural and physical-mechanical properties of the overburden strata.