中关铁矿采场回采进路宽度优化与应用

Optimization and Application of Mining Approach Width in Zhongguan Iron Mine

合理的进路宽度对充填采矿法在深部采场实现安全高效生产具有重要作用。采用数值分析方法,分析了中关铁矿5种进路宽度下的围岩应力分布规律、位移量变化和塑性区分布特征,研究了进路宽度对围岩稳定性的影响,优选出最佳回采进路宽度,并通过现场实践进行验证。结果表明:顶底板拉应力集中区呈“驼峰”状分布,应力值与距进路顶板的距离成正相关;侧帮压应力集中区呈“扇形”弧状向两侧分布,应力值先升后降,距侧帮1 m处出现应力峰值,围岩破坏可能性极大;顶板下沉量呈“中间大、两侧小”的凹状对称形态,顶板下沉量及其增幅远大于侧帮的位移量与增幅,进路宽度继续增大易引发顶板垮落事故;塑性区在形态上呈左右对称分布,体积上随进路宽度增大而增加,6 m宽度后体积增幅显著提升。现场实践表明,6 m进路宽度下,8N3采场围岩稳定性良好,回采率达到93%,贫化率13%,生产能力1400 t/d,应用效果良好。

Reasonable approach width plays an important role in achieving safe and efficient production in deep stopes mined by fill mining method.Numerical analysis method was used to analyze the stress distribution law,displacement change and plastic zone distribution characteristics of surrounding rocks under 5groups of approach width in Zhongguan Iron Mine.The influence of approach width on the stability of surrounding rocks was studied,and the optimal approach width was selected and verified by field practice.The results show that the tensile stress concentration area of the roof and floor is distributed in the shape of a hump,and the stress value is positively correlated with the distance from the roof of the approach.The compressive stress concentration area of the side wall is distributed to both sides in the shape of a fan arc,the stress value first rises and then falls,the stress peak occurs at 1mfrom the side wall,and the possibility of damage to the surrounding rocks is very great.The amount of roof subsidence is in a concave symmetrical pattern of“big in the middle and small on both sides”,and the amount of roof subsidence and its increase is much larger than the displacement and increase of the side wall,so the continues increase in the approach width is prone to cause roof collapse accidents.The plastic zone shows a left-right symmetric distribution in morphology and increases in volume with the increase of the approach width,and the volume increase is significantly increased when the approach width is larger than 6m.The field practice shows that the stability of surrounding rocks in 8N3stope with 6mapproach width is good,the recovery rate is 93%,the dilution rate is 13%,and the production capacity is 1400t/d,with agood application effect.