Application of dense hole control blasting block technology in Hequ Open-pit Mine
In order to solve the problem of high boulder rate of white sandstone hard top bench blasting in Hequ Open-pit Mine,Controlling technique measures were proposed to arrange external holes.By adding short holes without charge between ordinary holes,free surfaces are increased,and the blasting stress wave is reflected by the free surface to form tensile stress wave,so as to improve the crushing effect.This article expounds the action mode of the stress wave in the densified hole,and carries out field tests.Different schemes are adopted at the same step,and the experimental results are compared and counted.After adopting densified hole scheme,the average fragmentation of blasting is 1 244.4 mm×773.4 mm×707.9 mm reduced to 417.6 mm×281.5 mm×219.4 mm.Finally,it is proved that the densified hole scheme has achieved obvious effect in the white sandstone step.
blasting optimizationhard top stepblock controldensified empty holeexplosion stress wave
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