# Shaft Wall Damage to High-Depth Inclined Ore Passes under Impact Wear Behavior
## 2 Shaft Wall Damage Model for High-Depth Inclined Ore Passes
### 3 Engineering Case
#### 3.1.3 Result Analysis  
To validate the rationality of the proposed shaft wall damage model for high-depth inclined ore passes, numerical models for operating conditions 1, 2, 3, and 4 were constructed using the 2021 version of ABAQUS software [34; 35; 36], and the initial collision positions and the maximum ore indentation depths were quantitatively evaluated. In the numerical simulation, the material properties of four models were defined based on the physical and mechanical parameters shown in Table 1. The mesh types for all four models were set as CPS4I, with mesh quantities of 23,381, 21,590, 22,608, and 22,256, respectively. Except for the unconstrained inner wall of the ore pass, complete fixed constraints were applied to the other boundaries of the models. The failure of the shaft wall rock mass obeys the Mohr-Coulomb criterion. The numerical simulation results for the four operating conditions are presented in Figure 5.  
As can be seen from Figure 5, it is evident that there are variations in the initial collision positions and the maximum ore indentation depths between the four operating conditions. Specifically, changes in the maximum ore indentation depth exhibit a radiating distribution from the collision center toward the surrounding areas, with a gradual decrease in magnitude. The calculated results for the initial collision positions and maximum ore indentation depths obtained via the numerical simulation and theoretical model are shown in Figure 6.  
Figure 5: Numerical simulation results of the maximum ore indentation depth at the initial collision positions. (**a**) Operating Condition 1; (**b**) Operating Condition 2; (**c**) Operating Condition 3; (**d**) Operating Condition 4. From Figure 6, it can be observed that the calculated results of the initial collision positions and the maximum ore indentation depths obtained from both the theoretical model and numerical simulation have a consistent trend. Owing to factors such as the mesh partitioning accuracy, boundary condition settings, component interactions, and nonlinear behaviors in the numerical simulation, there is a certain degree of error in the results obtained by means of both calculation methods. The relative errors in the maximum ore indentation depths are all within 5%, and the relative errors in the initial collision positions are around 15%. Considering the research area with a shaft diameter of 2 m and a height of 10 m, these errors can be considered negligible. An analysis of Figure 6 further indicates that the maximum ore indentation depths for operating conditions 3 and 4 are relatively deep and close, while the maximum ore indentation depth is smallest for operating condition 1. Through field investigations, the damage conditions of the shaft walls of the four ore passes in the mine were understood. The shaft wall of No. 1 ore pass (operating condition 4) experienced extensive collapse, and the ore pass is now out of use. The shaft wall of No. 3 ore pass (operating condition 3) suffered severe wall damage, resulting in the blockage of the ore bin opening, and this ore pass has been abandoned. The shaft wall of No. 2 ore pass (operating condition 2) has a moderate level of shaft wall damage, with occasional occurrences of large ore blockages at the ore bin opening. No. 2 ore pass can continue operating after the rebar bound charge blasting vibration method is used to dredge the blocked position. Residual fragmented ore rocks are visible at the bottom of No. 2 ore pass (Figure 7). The shaft wall of No. 9 ore pass (operating condition 1) has minimal wall damage, with virtually no instances of wall collapse or ore blockages, and this ore pass is in normal operation. This indicates a complete alignment between the computed results obtained using the theoretical model and numerical simulation and the actual engineering situations.