急倾斜厚层矿体分段空场式开采安全性评价

Safety Evaluation on Sublevel Open Stope Mining of Steeply Inclined Thick Orebody

大桥头方解石矿在大桥头铅锌矿和仙洞方解石矿整合以后,亟需对新开采条件下的分段空场留矿式开采工艺参数进行评价。基于矿体赋存条件和分段空场采矿工艺,根据岩层极限平衡理论计算分析了岩(立)柱宽度的稳定性,开采深度越深,岩柱宽度应越大,在+200 m段留8.0 m,在+150 m段留9.0 m,在+100 m段留10.0 m。根据岩石力学理论,计算分析了空场跨度,开采深度越深,空场跨度应越小,在+200 m段跨度60 m,在+150、+100 m段跨度45 m。采用UDEC模拟软件对8 m岩立柱、空场顶底板稳定性进行了分析,矿体开采以后在各段顶板中形成的承载拱结构使得空场及岩柱均可保持稳定。采用FLAC3D数值模拟方法对分段开挖垂直位移进行分析,上段开采对本段开采造成扰动影响较小,底柱由于埋深侧向压力的对向挤压出现大幅度上鼓并产生塑性区。工程实践表明,以优化后的开采工艺参数进行开采是安全可靠的。

After the integration of Daqiaotou lead zinc mine and Xiandong calcite mine,it is necessary to evaluate the technological parameters of sublevel open stope mining under the new mining conditions.Based on the ore body occurrence condition and sublevel open stope mining technology,the stability of the width of the rock(vertical)pillar is calculated and analyzed according to the limit equilibrium theory of the rock stratum.The deeper the mining depth is,the larger the width of the rock pillar should be,leaving 8.0 m in the+200 m section,9.0 m in the+150 m section and 10.0 m in the+100 m section.According to the theory of rock mechanics,the open field span is calculated and analyzed.The deeper the mining depth is,the smaller the open field span is.The span is 60 m in+200 m section,45 m in+150 m and+100 m section.UDEC simulation software is used to analyze the stability of 8m rock column and roof and floor of the open field.The bearing arch structure formed in the roof of each section after the mining of ore body makes the open field and rock column stable.FLAC3D numerical simulation method is used to analyze the vertical displacement of the section excavation.The mining in the upper section has little impact on the mining in this section,and the bottom column bulges greatly due to the opposite compression of the lateral pressure of the buried depth and produces a plastic area.The engineering practice shows that it is safe and reliable to mine with the optimized mining process parameters.