# Shaft Wall Damage to High-Depth Inclined Ore Passes under Impact Wear Behavior
###### Abstract  
In order to study shaft wall damage resulting from ore drawing in ore passes, a theoretical model for predicting the shaft wall damage to high-depth inclined ore passes is constructed based on field surveys of 25 ore passes in a deep mine in Yunnan, China. The mathematical expression of the total shaft wall damage volume is derived using the contact mechanics theory. Considering the structural characteristics of ore passes, and taking No. 1, 2, 3, and 9 ore passes as examples, combined with numerical simulation and an engineering case, the rationality of the proposed theoretical model is verified with respect to the initial collision position and the damage conditions of the shaft wall. The influence of, and sensitivity to, the ore block size \(P\) and the structural parameters of high-depth inclined ore passes on the total shaft wall damage volume \(Q_{\text{tol}}\) are quantitatively analyzed. The results show that the calculation results of the theoretical model and numerical simulation are in good agreement with the actual engineering situations. Moreover, the ore-pass dip angle \(\theta\) and the inclined angle of the chute \(\alpha\) have a significant impact on the damage to the shaft wall, while the effects of the ore-pass depth \(H\) and the shaft diameter \(D\) are comparatively minor. With an increase in \(\theta\) or \(\alpha\), \(Q_{\text{tol}}\) generally first increases and then decreases. \(Q_{\text{tol}}\) increases exponentially with \(P\) and increases steadily with \(D\). \(H\) affects \(Q_{\text{tol}}\) by influencing the collision frequency between the ore and the shaft wall. Therefore, in the mining design of deep mines, \(\theta\) and \(\alpha\) should be minimized as much as possible or adjusted to approach \(90^{\circ}\), thereby reducing damage to the shaft wall. Secondly, ore block size should be strictly controlled to prevent collapses in the shaft wall caused by large ore blocks. This work provides technical support for the long-term safe operation of high-depth inclined ore passes. deep metal mine; high-depth inclined ore-pass; shaft wall damage area; ore block size; impact wear behavior +
Footnote †: journal: Applied Sciences
on the erosion wear theory and the Hertz contact theory. [PERSON] et al. [9; 10] determined the initial collision position distribution of ore transporting in a vertical ore pass and deduced a three-dimensional moving track equation before collision. [PERSON] et al. [11] studied changes in the internal force chain structure of bulk ores under discharge impact at different heights using the PFC (Particle Flow Code) numerical simulation. Through similarity experiments on ore drawing in an ore pass, [PERSON] et al. [12; 13] obtained the ore moving track and the shaft wall wear range and developed a panoramic scanning imaging device for use in vertical ore passes. [PERSON] et al. [14] recorded changes in rock strata using the total station observation method, revealing the impact point distribution and its failure rule for ore drawing in vertical ore passes with different geological structures. [PERSON] et al. [15; 16] analyzed the stress state around the chute using three-dimensional boundary elements to study the shaft wall failure mechanism under impact load and material flow wear. [PERSON] [17] built a lateral pressure theory on the basis of lateral pressure and coefficients of lateral pressure using the micromechanics theory. [PERSON] et al. [18] proposed an ore-pass scanner based on interferometer synthetic aperture radar (InSAR) time series to monitor potential collapse areas in the shaft wall. In addition, scholars have conducted preliminary studies on the influencing factors of shaft wall damage for ore passes, such as the shape and size of the extracted ore [19; 20], the size of the ore pass [21], the drawing speed [22], and the crack of surrounding rocks [23].