关键词: 破碎难采矿体, 分段凿岩阶段出矿, 数值模拟, 宽度优化, 预控顶巷

Abstract: To optimize the stope width in the sublevel drilling and stage caving with subsequent back⁃ filling mining method at Zhongguan Iron Mine，and to achieve safe and efficient extraction of fractured and difficult-to-mine ore bodies，numerical simulations were conducted based on the optimized results of the stope's maximum allowable exposure dimensions derived from the Mathews stability graph method. Simula⁃ tions were performed for a stope height of 30 m and widths of 10，12，14，16，and 18 m. By comparing and analyzing the vertical stress on the stope roof，horizontal displacement of the side walls，and the develop⁃ ment of plastic zones under different width scenarios，the rational stope structural parameters were further determined. The results indicate that the stope remains stable when the width is no more than 10 m. When the width increases to 12 m，additional reinforcement of the central roof area is required to maintain stabili⁃ ty. For widths ranging from 14 to 18 m，stope stability is significantly compromised. Based on these find⁃ ings，engineering practice was implemented using the sublevel drilling and bench caving with delayed back⁃ filling mining method，with stope dimensions of 30 m in height，12 m in width，and a length not exceeding 50 m. A roof protection drift was constructed at the middle of the stope roof at the -200 m level. A combined pre-support technique using prestressed long cable bolts，mesh，and shotcrete was applied for proactive roof control. Field practice demonstrates that the stope achieves a production capacity of 3 170 t/d，with an ore recovery rate of 88.35%，a dilution rate of 10.17%，and excellent stope stability. This confirms the feasi⁃ bility of safe，efficient，and economical mining operations.

Key words: fractured and difficult-to-mine ore bodies, sublevel drilling and stage caving, numerical simulation, width optimization, pre-controlled top lane