Abstract: In order to determine the more reasonable stope structural parameters under different geological conditions,theoretical calculation and numerical simulation methods are adopted to select and optimize the stope width under different stability.With the western area of Chengchao Iron Mine as engineering background,the simply supported beam theory and the stope width calculation formula are used to calculate out the reasonable span and the critical span.And the stope stability under different stope width was analyzed by FLAC3D software.The results indicated that when rock keeps stable,moderately stable or less stable,the reasonable stope width needs to be 18.87 m,14.93 m and 8.08 m separately.In multi-stope mining,maximum displacement and tensile stress usually occurs in the middle of the area,and the increase of stope span can easily cause a rapid increase of maximum displacement.The subsidence of pillar roof also greatly impacted the stope span.The simulation results were consistent with the theoretical value,which indicates that the numerical simulation can well reflect the real state of underground mining,and provide the basis for determining stope structural parameters.

Key words: Stope width, Numerical simulation, Geological condition, Minimum principle stress, Plastic zone