大断面六角形进路采矿法结构参数优化研究

Study on Optimization of Structural Parameters of Hexagonal Mining Method with Large Cross-section

针对龙首矿普通六角形进路采矿法在西一贫矿区回采过程中进尺率低、断面轮廓不规整、机械化程度低和炸药单耗高等回采问题,通过数值模拟和现场试验,对大断面六角形进路采矿法在龙首矿西一贫矿开采区的可行性进行研究。结果表明:与普通六角形进路采矿法相比,采用大断面六角形进路采矿法回采西一贫矿资源时,采场顶底板及边帮矿岩受力条件更好,顶底板变形量小,2条相邻进路之间未出现贯通;平均进尺由2.4 m提高至3.2 m,提高了33.3%;炸药单耗由0.20 kg/t降低至0.15 kg/t,降低了25%;轮廓完整性更好,最大超挖量降低了97 cm,最大欠挖量降低了10 cm;凿岩效率由1.25 m/min提高至2.10 m/min。研究结果证明了大断面六角形进路采矿法在龙首矿西一贫矿开采区回采过程中的可行性,符合回采过程中对安全性和高效的要求。

The reasonable selection of stope structural parameters is a key process in mining design,which has an important influence on stope stability,blasting drilling depth,explosive consumption,mining efficiency and stress state of surrounding rock.Reasonable stope structural parameters are conducive to improve the stress conditions during route mining,reduce the stress and strain values of surrounding rock around the stope,reduce the support workload and improve the mining efficiency under the condition of ensuring safe mining.Based on the lean ore resources mining in the Xiyi mining area of Longshou Mine,Jinchuan Group,we use bionic principle to design the mining route with honeycomb hexagonal structure,so as to improve the surrounding rock stress conditions,improve the stope stability and effectively control the crustalstress.Xiyi mining area is located between 17 and 34 rows in the west mining area of Longshou Mine,Jinchuan Group,and between level of 1220 m and 1520 m.Adopt the general hexagonal section mining method for mining,with the section specification of 4 m*6 m*5 m(top and bottom width*waist width*height)practice has proved that,the adaptability of the section specification and borehole layout to the broken ore body in Xiyi lean mine is poor.Aiming at the problems of low drilling depth rate,irregular cross-section outline,low mechanization degree and high explosive consumption in the process of general hexagonal approach mining in Xiyi lean mining area of Longshou Mine,this study adopted empirical analogy method and proposed a hexagonal approach mining method with large cross-section size of 4 m*8 m*8 m(top and bottom width*waist width*height).Based on FLAC3D software,the excavation and filling process of the test roadway were simulated numerically and analyzed.The maximum principal stress appears in the top plate of the route,the minimum principal stress lies in the bottom plate and the lower side of the route,and the stress concentration phenomenon appears in the upper part between the two access roads.And then field tests were carried out according to the designed mining technology to study the feasibility of the large cross-section hexagonal roadway mining method in the Xiyi lean mining area of Longshou Mine.Research indicates:Comparing ordinary hexagonal mining method,when the large cross-section hexagonal approach is adopted to mine the resources of Xiyi lean ore mining area,the stope roof and floor,and side rock are under better stress conditions,the roof and floor deformation is small,and there is no connection between the two approaches.In the lower inverted trapezoid mining,the step blasting driving method is adopted,which increases the free surface in the vertical direction and reduces the rock clamping effect during blasting.The average footage increased from 2.4 m to 3.2 m,increase by 33.3%.The explosive unit consumption is reduced from 0.2 kg/t to 0.15 kg/t,and the explosive consumption is reduced by 25%.Due to the reasonable arrangement of blastholes and the design of initiation sequence,the explosive energy is released in turn during blasting,and the damage of blasting vibration to the side wall and bottom plate is less.This improves contour integrity,maximum over-excavation reduced by 97 cm,maximum under-excavation reduced by 10 cm.At the same time,it is also conducive to the formation of the next layered hexagonal route.Due to the large working space of large section hexagonal drift mining method,Boomer double arm drilling jumbo is designed to drill,which greatly improves the drilling efficiency and safety.And rock drilling efficiency increased from 1.25 m/min to 2.10 m/min.It proves the feasibility of the large-section hexagonal approach in the mining process of the Xiyi lean mining area of Longshou Mine,and realize the requirements for safety and efficiency in the mining process.