露天金矿控制矿体位移爆破数值模拟与生产试验研究

Research on numerical simulation and production test of blasting displacement controlled of ore body in open-pit gold mine

在矿体具有“鸡窝状分散分布”赋存特点的露天金矿中,需要优化全生产周期的各个环节来降低金矿石的损失与贫化,研究并优化爆破导致的矿岩体位移是重要途径之一。以青海某露天金矿生产现状与爆区位移较大的问题为基础,采用ANSYS/LS-DYNA软件对爆区中间断面4排炮孔进行建模,通过SPH光滑粒子流体动力学方法进行计算分析得到压渣层厚度为2 m时可以将爆区内部点位的隆起和水平位移限制在1 m以内,进而将压渣层厚度优化确定为5 m。结合矿山实际,围绕布孔方式、孔网参数与起爆网路提出6套综合性对照方案进行18组生产试验,统计分析爆区内4个标志点位移数据得到:对于爆破位移控制效果,小V优于大V优于斜线起爆,矩形布孔略优于三角形布孔;综合对比确定该矿山矿岩体位移控制最优爆破方案为“矩形3 m×3 m布孔+小V中间起爆”,可将隆起和水平平均位移控制在0.77、0.52 m,较以往降低了约50%,经后续生产实践验证可以满足金矿取样圈矿、分选采装以及最终选冶要求。试验思路与成果为今后进一步的优化研究提供了基础,对类似矿山的生产实践具有一定的参考价值。

In the open-pit gold mine where the ore body has the occurrence characteristics of nest-like dispersed distribution,it is necessary to optimize all links of the whole production period to reduce the loss and dilution of gold ore.Studying and optimizing the displacement of ore and rock mass caused by blasting is one of the most important approach.Based on the production status of an open-pit gold mine in Qinghai Province and its problem of large displacement of the blasting area,ANSYS/LS-DYNA software is used to model the 4 rows of blast holes in the middle section of the blasting area.Through the calculation and analysis by SPH smooth particle hydrodynamics method,it is obtained that when the thickness of the slag layer is 2 m,the uplift and horizontal displacement of the points inside the blasting area can be limited within 1 m,and then the thickness of the slag layer is optimized to 5 m.Combined with the actual situation of the mine,six comprehensive comparison schemes were put forward around three factors including hole layout,hole network parameters and detonating network,and then 18 groups of production tests were carried out.The statistical analysis of the displacement data of four landmark points inside the blasting area showed that:for the blasting displacement control effect,small-V was better than large-V than oblique line detonation,and rectangular hole layout was slightly better than triangular hole layout.Through comprehensive comparison,it is determined that the optimal blasting scheme for the displacement control of the ore and rock body of the mine is"rectangular 3 m×3 m hole layout&small-V intermediate initiation",which can control the uplift and horizontal average displacement at 0.77 m and 0.52 m respectively which are about 50%lower than the past.The subsequent production practice has verified that it can meet the requirements of the gold ore delineation,sorting&loading,and smelting.The test ideas and results provide a basis for further optimization research in the future,and have a certain reference value for the production practice of similar mines.