Optimization Of Open-pit Groove Blasting In A Gold Mine In Inner Mongolia

Strip mining needs a lot of digging trenches to form free surface of the steps,the blasting condition of grooved blasting is poorer,the bottom of the step has greater force and it is easy to appear bedrock.The blasting effect of grooved blasting directly affects the mine economic benefit.Currently there is a large problem of the mine bedrock in a gold mine in Inner Mongolia,and unreasonable blasting scheme is the main factor of bedrock.Therefore,it is imperative to research on trench blasting,make possible optimization scheme,improve the trench blasting effect and solve the problem of bedrock.Taking grooved blasting of the gold mine as the research object,it is analyzed the reason for the occurrence of bedrock and defined proper handling program.ANSYS/LS-DYNA is used to simulate the blasting process,according to the simulated data,puts forward the optimization scheme.The main research work and achievements:(1)Based on the geological conditions of the mine and the current situation of the mining,it is analyzed the cause of the existing problems at the stage,combined with the practical conditions of the mine,and put forward the corresponding solutions.The results show that using numerical simulation method to optimize the ultra-deep is one of the most effective way to solve the problem.(2)The software of ANSYS/LS-DYNA is used to simulate charge blasting under the single free surface.The stress nephogram is be used to analyze stress wave propagation and stress distribution.Based on rock failure criterion,by contrast the peak stress and the dynamic tensile strength,range rock damage range of different levels can be determinate,then blasting funnel shape can be get.The results show that numerical simulation software can be used to quantitative analysis of rock damage,and it is feasible to use blasting crater radius of the free surface and sub-bottom rock blasting damage radius to evaluate the effect of the trench after analysis.(3)The relevant numerical calculation model was set up in consideration of the actual blasting environment and parameter.Analyzed the change of blasting crater radius and the rock damage radius at the section bottom by changing exceeded length of hole in the model.Using these two radius to evaluate grooved blasting effect,and get reasonable exceeded length further more.The results shows that,the blasting crater radius of free surface getting smaller gradually with the increase of exceeded length.The rock damage radius at the section bottom increased gradually,and showed a trend of gradually gentle.According to the results of different blasting scheme,the reasonable exceeded length get from numerical calculation can improve the grooved blasting effect and root problem effectively at hole-diameter of ?140mm or ?100mm.(4)Optimization of grooved blasting by numerical simulation is not only applied on trench engineering in the mine,but also in other grooved blasting.It effectively save manpower,material resources,and financial power,and overcome the disadvantages of unrepeatable in the field blasting experiment.After the study,deepen the understanding of grooved blasting mechanism,obtain the judgment of grooved blasting effect,and put forward reasonable optimization scheme for the gold mine.