金川龙首矿中深孔破坏规律及护孔措施

金川龙首矿西二采区拟采用无底柱分段崩落法代替胶结充填法开采低品位矿石,从而寻求降低采矿成本的新途径。该矿地质条件复杂,中深孔能否成孔以及是否具有较好的保持率,是无底柱分段崩落法能否顺利实施的关键。采用不连续变形分析方法对西二采区地质条件下的中深孔破坏形式及规律进行了分析,得出中深孔最易发生破坏的部位主要集中在巷道周边破坏矿体区域内;在1610 m分段5行联络道围岩及5#进路矿体中进行了现场试验,以测定实际情况下的炮孔破坏情况,结果表明,中深孔的保持率较高,施工2个月后达到了91.7%。为进一步提升西二采区中深孔保持率及爆破效果,提出了为回采进路选择合理的支护形式、适当增大中深孔孔径、在孔口部位采用大直径锚杆护孔、采取合理的回采顺序、加强透孔及补孔等措施,可为龙首矿西二采区中深孔的施工提供借鉴。

Study on the failure law and the control measures of the medium and long holes in Longshou Mine,Jinchuan

Sublevel caving without sill pillar method is intended to be employed for mining of the low-grade ore with replacement of cement-filling mining method in west mining zone No.2 of Longshou Mine in Jinchuan for approaches to a novel solution to reduction of mining cost.Because of its complicated geological conditions,the medium and long holes with high retention rate are the key to implement the sublevel caving without sill pillar method successfully.In this paper,discontinuous deformation analysis method was used to study the failure law and form of medium and long holes under the existing geological conditions in west mining zone No.2.It is concluded that the most vulne-rable parts of the holes are mainly located around the damaged ore body on perimeter of roadway.The field test was carried out on the surrounding rock in No.5 contact way and on the ore body in 5#access at sublevel of 1,610 m to determine the failure of holes under the actual conditions.The field test results show that the medium and long hole maintains a high retention rate even up to 91.7%after two months of construction.In order to further improve the retention rate and blasting performance,some measures including selecting rational supporting form,increasing the diameter of medium and long holes appropriately,using bolts of large diameter to protect the hole opening,employing a reasonable stoping sequence,making all the hole through and reperforating if necessary were proposed and to be provided as the reference for construction of the medium and long holes.