Study On Reasonable Extra-depth Of Bench Blasting In Huangmai-Ling Mine

The bench blasting is mainly used in mining, soil and stone excavation of railway, highway and water conservancy. It is a blasting technique which will be used broadly. The quality of bench blasting generally has the following requests:(1)The dimensions of ore and rock can meet the requirement after project blasting;(2)The step working surface must be neat after blasting, not allowing the phenomena that exists bedrock and umbrella rock. The Sub drilling is an important blasting parameter to eliminate bedrock. The purpose of sub drilling is to mark down the height of loading central, to increase explosive payload in toe hole to conquer resistance of bench bottom, thus it will eliminate bedrock, to make bench bottom smooth.In this paper, the object of research is bench blasting in Huangmai-Ling mine. Analyses of the mechanism of the sub drilling of eliminate bedrock and the influence of blasting parameter changing to the sub drilling. the elastic-plastic isotropy and multi-notched holes are set up, dynamical finite element analysis software ANSYS/LS-DYNA is applied, dynamic stress distribution and its change rule of rock between and around two holes is calculated, And influence of blasting parameter changing to the sub drilling is discussed. The main research achievements and conclusions are as follows:(1) Through the analysis of rock-breaking and sub drilling in bench blasting, this paper interprets the effect of sub drilling in the aspect of eliminate bedrock, introduces the main influencing factors of sub drilling, including the qualities of rock and detonator and blasting parameters.(2) use ANSYS/LS-DYNA software to conveniently compare the changes of sub drilling in chassis resistance line and the inter space of two holes, the simulation results show:the chassis resistance line of a great influence on sub drilling in the other conditions the same Case, the change in the size of the chassis resistance line, the sub drilling must to change. But the specific value of the sub drilling and chassis resistance line remained unchanged.(3) According to Huangmai-Ling mine geology, existing equipment and blasting parameters, the use of ANSYS/LS-DYNA software to simulate the process of bench blasting, analysis of the results obtained by simulating Huangmai-Ling mine reasonably depth of sub drilling.(4) We experiment the parameters in Huangmai-Ling mine and analyses and compare with different effects between parameters which result from academic calculate. and then summarize the rational sub drilling in Huangmai-Ling mine.