An investigation of the coal wall zoning failure patterns resulting from the changes in support parameters of large mining height

To address control of the coal wall rib spalling in a work face with large mining height, an investigation was conducted on the Caojiatan mine 122107 work face as a case study. Using a combination of theoretical analysis, orthogonal experiments, and numerical simulations, we determined the influence of hydraulic support parameters on coal wall rib spalling. Our results show that reducing the end-face distance and the resultant force application point and increasing the vertical force and the horizontal force of a hydraulic support provide increased stability of the coal wall. Extensive verification was made through simulations. The work presented herein suggested a structural zoning of the coal wall rib spalling, it also established the coal wall stability coefficient, and determined the lower limit of the coal wall’s nonstructural area stability coefficient. Additionally, this study provided methods for the prevention and control of coal wall rib spalling in a large mining height work face, via improving the nonstructural area mechanical parameters, and optimization of the hydraulic support.