Bench blasting is an important link in open pit mining.Its blasting effect directly affects the efficiency of subsequent shovel loading and transportation.Blasting design,rock properties,geological structure and other factors have a great impact on the blasting effect.In order to reduce the root and large blocks and improve the blasting effect,the optimization simulation study of blasting parameters is carried out based on the No.9 pass lowering project in Zijingshan Gold and Copper Mine.The mechanical parameters of the rock were determined through experiments.Three groups of blasting models with different hole mesh parameters were established through LS-DYNA software.The stress nephogram of the initiation process was observed and the stress response of the blasted rock was analyzed.It was concluded that the peak tensile stress of the rock in the crack zone was the dominant role in its fragmentation.Then combined with the rock fragmentation theory,the peak tensile stress of the blasted rock under different hole network parameters is analyzed one by one,and compared with the dynamic tensile strength of the rock to judge its fragmentation effect,and the optimal hole network parameters are obtained.Through numerical simulation optimization and field test,the blasting effect has been significantly improved,and the efficiency of shovel loading and transportation has also been greatly improved.This model can provide a reference for the optimization of hole network parameters in similar blasting projects.

In the realm of open-pit mining, the characterization of blast pile fragmentation poses significant challenges. This study pioneers a novel approach, harnessing the capabilities of 3D laser scanning technology to acquire comprehensive spatial data of blast piles. Essential to this research is the deployment of sophisticated data processing techniques, including the Random Sample Consensus (RANSAC) for plane fitting and Density-Based Spatial Clustering of Applications with Noise (DBSCAN) for clustering algorithms, to meticulously delineate the contours of rock blocks within blast piles. The innovative methodology facilitates swift determination of rock block volumes and their maximum particle dimensions through the calculation of 3D convex hulls and Oriented Bounding Boxes (OBB). Additionally, the application of Delaunay triangulation to the blast pile's 3D point cloud data culminates in the creation of a detailed mesh model, from which the blast pile's volume is accurately derived using projection methods. Rigorous indoor testing has yielded a relative error margin of approximately 4.61% for block volumes and 4.75% for particle diameters under stacked conditions. In practical field applications, the method exhibits commendable accuracy, with an average rock block identification accuracy of 80.4%, increasing proportionally with the size of the rock blocks. The calculated volume of the blast pile closely mirrors actual excavation volumes, manifesting a relative error of 4.85%. Computational errors for key metrics such as the blast pile's height, forward throw distance, and lateral extent were found to be 2.92%, 3.91%, and 4.29%, respectively. The findings of this study are instrumental in assessing blasting effectiveness and in refining blasting parameters, marking a significant advancement in the field of open-pit mining.

随着现代计算机理论技术的发展,许多学者基于计算机理论技术对短时非线性信号分解方面的研究也越来越成熟.变分模态分解(VMD)方法以其具有数学逻辑性强,抗噪性明显的优势已在其他振动领域得到广泛的发展.本文介绍了变分模态分解的基本理论,采用仿真信号对变分模态分解方法进行测试,并与经验模态分解方法进行对比分析,研究结果表明变分模态分解具有精准的识别能力,最后将此方法应用到紫金山金铜矿实测爆破振动信号中,取得了良好的效果.

In order to investigate the dynamic mechanical behavior of composite rock in deep-buried tunnels, the dynamic impact tests of the combinations with three lithologies (granite-H, cyan sandstone-S1, and red sandstone-S2) and six kinds of composite forms (H-S1, S1-H, H-S2, S2-H, S1-S2, and S2-S1), were carried out in this study. Additionally, the effects of the combination forms and strain rates on the stress-strain curve, peak stress, energy utilization rate (EUR), failure process, displacement field, and failure mode of the composite sample were analyzed. The results show that the peak stresses of all the combinations are linearly and positively correlated with the strain rate. When the strain rate is close, the peak stress and elastic modulus of the combination with front hard and rear soft (FHRS) rocks are larger. Furthermore, the EUR of different combinations is proportional to the incident energy. The EUR of the front soft and rear hard (FSRH) combination is generally higher than that of the FHRS combination. In general, the rock with low strength always fails first in the composite. When the strength disparity between the two rocks of the composite is small, the failure of the composite with FSRH is relatively small, and the main deformation occurs in the rock with low strength. Finally, the fractal dimension of the fragments after the impact of the FSRH combination is larger, i.e., the lumpiness of fragments is closer.

随着我国露天矿开采深度不断加大,永久边坡的稳定性已逐步被关注.预裂爆破在矿山施工方法中已得到广泛应用,并取得良好的效果.文章以紫金山金铜矿凹陷采场为背景,介绍了本工程预裂爆破相应的施工参数,对核心施工技术要点进行阐述,该技术的成功应用使露天矿爆破振动危害降低,其中半孔率达到75％,爆破振动峰值振速控制在0.5cm/s以下,垂直方向最大减振率高达81％,达到了良好的效果,为同类施工现场提供经验.

本文介绍了一种爆破振动信号处理方法——微分经验模态分解(DEMD),并结合多宝山铜矿选矿厂中碎车间基础爆破振动监测试验,与经验模态分解(EMD)进行对比分析爆破振动信号的频率筛分、混叠失真情况以及分解后信号的功率谱特性.结果 显示:与EMD相比,DEMD有效地抑制了信号混叠失真现象,且从信号的功率谱变化特征得出DEMD将不同的优势频率分量提取出来,爆破振动信号频率筛分效果优越于EMD.

多宝山铜矿处于高寒地区,常年的冻融循环作用以及台阶爆破的扰动影响了矿岩台阶的物理力学性质,按照原有的爆破参数进行设计并施工,爆破效果往往不理想,主要是大块率偏高、底根较多.为此,采用进化径向基神经网络方法对孔网参数、炸药单耗、排间延期时间等爆破参数进行优化,根据神经网络的训练与预测结果,最终得出了一套适用于多铜矿岩台阶爆破的最优爆破参数,通过进行一系列的现场爆破试验,并与之前的爆破效果进行对比,大块率显著降低,炸药单耗有所下降,提高了铲装的工作效率,节省了爆破成本,取得了良好的爆破效果,并增加了采矿经济效益.此方法科学可行,适用于多宝山铜矿的台阶爆破参数优化.

为了研究斑铜矿在不同冲击荷载下的动态力学特性,通过霍普金森试验,对斑铜矿进行冲击试验,分析研究结果表明:斑铜矿的平均应变率与冲击荷载有着很强的相关性,两者之间多项式拟合关系水平明显.在冲击荷载的作用下,应力应变曲线表现为四个发展阶段:裂隙闭合阶段、弹性裂隙稳定扩展阶段、非线性弹性变形阶段、最终破坏阶段,存在一个破碎块度的均匀适中的冲击气压,而在较高冲击荷载下的破坏模式为压碎破坏.对冲击后的岩样进行筛分粒度分级的结果表明:冲击荷载越大,破碎块度越小.

According to the condition of the east ending to open-pit in Zijinshan Gold-copper Mine,blasting methods are taken to protect the stability of slope and the reasonable blasting parameters will be obtained through the experiments that will help provide a basis for the blasting of ending slope in the future.

Some measures were taken in controlled blasting for surface mining of ore body overhanging on both sides,such as ① making good use of landform and ground objects for the determination of blasting parameters and hole layout;② precisely calculating explosive charges for each hole with proper adjustment;and ③ using the condition of location overhanging on both sides to design ignition network and delay time interval which ingeniously uses the ignition moment to offset the anti-action resulted from blasting.These measures guaranteed construction safety and blasting quality and a satisfactory blasting effect.