To balance stope stability with mining economy and to inform stope span design in similar engineering projects, a comprehensive investigation was conducted on the stope span and its stability, using the -200 m level of a copper mine as a case study. The Mathews stability chart method was adopted to evaluate the stope stability by calculating the rock mass stability index and hydraulic radius, thereby defining a reasonable range of stable stope spans. Based on the analysis, four stope span scenarios were designed and numerically simulated using finite difference software to study the stope responses. Comparative analyses were performed on roof displacements and the characteristics of plastic zones in the surrounding rock. The results show that as the stope span increases from 12 m to 18 m, vertical displacement of the roof increases gradually, and the volume of the plastic zone fluctuates slightly. However, when the span reaches 20 m, a significant increase in roof displacement and a sudden expansion of the plastic zone which leads to through-going failure is observed, severely compromising roof stability. An optimal stope span of 18 m is recommended for the -200 m level of the copper mine. The stope span design of mining should consider the influence of factors such as orebody occurrence conditions, safety and efficiency.

thick orebody  /  stope span  /  graphical method  /  numerical simulation  /  stope stability