露天坑胶结充填对挂帮矿开采稳定性影响分析

Analysis of the influence of cemented filling in open pit on the stability of hanging-wall ores extraction

为解决冬瓜山铜矿富余尾矿出路及新桥硫铁矿露天坑治理问题,考虑利用冬瓜山铜矿富余尾矿对新桥硫铁矿露天坑进行胶结充填。露天坑东部尚有部分高品质挂帮矿,在露天坑胶结充填的同时必须协调解决挂帮矿安全回采难题。基于Flac^(3D)软件,构筑了露天坑挂帮矿开采与胶结充填耦合作用数值模型,进而分析了不同胶结充填高度和隔离矿柱留设厚度下,挂帮矿开采过程采场和露天边坡稳定性。结果表明:露天坑胶结充填高度分别为0 m、96 m和192 m时,对应的侧向隔离矿柱最小厚度分别为8 m、6 m和6 m;露天坑胶结充填后,露天平台承受上覆充填体应力增大,充填体覆盖条件下顶部矿柱最大拉应力值有所增长,但不影响顶部隔离矿柱留设厚度(8 m)。露天坑胶结充填有效改善了挂帮矿采场周围的应力场环境,减少了侧向隔离矿柱的留设厚度。在保证开采区域稳定性的同时,增大了挂帮矿回采的安全性。

In order to find a solution to the surplus tailings of Dongguashan Copper Mine and the treatment of the open pit of Xinqiao Pyrite Mine,the cemented filling in the open pit was considered by using the surplus tailings of Dongguashan Copper Mine.There are still some high-quality hanging-wall ores in the east of the open pit,and the challenge to safely extract the hanging-wall ores must be coordinated and solved at the same time of cemented filling in the open pit.Based on Flac^(3D) software,the numerical model of coupling action between mining and cemented filling with hanging-wall ores in open pit is constructed,and then the stability of stope and open pit slope in the process of hanging-wall ores extraction is analyzed under different cemented filling height and reserved pillar thickness.The results show that when the cemented filling height of the open pit is 0 m,96 m and 192 m respectively,the minimum thickness of the lateral isolated pillar is 8 m,6 m and 6 m respectively,and after the cemented filling of the open pit,the stress of the overburden on the open pit platform increases,and the maximum tensile stress of the top isolated pillar increases under the condition of backfilling,but it does not affect the reserved thickness of the top isolated pillar(8 m).The cemented filling in the open pit effectively improves the stress field environment around the hanging-wall ores stope and reduces the reserved thickness of the lateral isolation pillars.It not only ensures the stability of the mining area,but also improves the safety of hanging-wall ores extraction.