Drilling Angle Optimization In Blasting Of Shale Containing Vanadium By Experiment

Vanadium has extensive applications. China is abundant in vanadium resource,the occurrence form of which is shale containing vanadium, but its development andutilization is still in the initial stage. In order to improve the mining technologicallevel of shale containing vanadium, national "twelfth five-year" plan for science&technology support listed “key mining technology of complex multilayer shalecontaining vanadium”(No.2011BAB05B03) as an important research project. Shalecontaining vanadium is a kind of sedimentary with obvious bedding structure. Theresearch on the effect of bedding structure on drillability and blastability hastheoretical guidance meaning for the blasting of shale containing vanadium andsimilar layered rock mass. In the engineering background of shale containingvanadium in Shangheng mountain, Pengze country, Jiangxi province, this paperanalyses the influence of bedding structure on the blasting of shale containingvanadium by the way of theoretical analysis, indoor test, field test and numericalsimulation. The main research contents and achievements are as follows:(1) Starting from the basic theory of rock blasting damage, it analyses blastingprinciple of bedding rock with the explosive stress wave theory as the core.(2)Referring to the experiment of chiseling specific work, it compares the netdepth of borehole with different drilling angles under same working conditions. Theexperiment result shows that the drilling efficiency improve gradually with thedrilling angle ranging from0°to90°. Then, it analyses the particle size distributionof debris under different drilling angles by screening test, and verify the test resultsfrom the aspect of energy utilization.(3)In order to explore the reasonable borehole arrangement system for theblasting of shale containing vanadium, the field test was carried out in a shalecontaining vanadium in Hubei. Taking drilling efficiency, blasted rock’average size,block rate, block uniformity etc. as evaluation index, it analyses rock fragmentationby the digital image fragmentation analysis software of Split-Desktop. The testresults show that the reasonable borehole arrangement system for the blasting of shale containing vanadium is that hole is vertical to bedding and the free surface isparallel to the bedding.(4) The dynamic failure process of vanadium containing shale blasting underdifferent drilling angle, reasonable stemming length and initiation way are simulatedby explicit dynamic analysis software of ANSYS/LS-DYNA. The calculation resultsshow that the blasting effect of borehole of90°is best,0°is followed, and that theborehole is skewed with bedding should be avoided; When borehole depth is2m,the reasonable stemming length is60cm; The rational initiation method is reverseinitiation, followed by multi-point initiation, then positive initiation.