Optimization of Blasting Parameters in Huangmailing Open-pit Mine

Hole-by-hole blasting technique has been applied in Huangmailing open-pit mine.There are such problems as high boulder yield,frequent toe rock and so on in the process of production,so the optimization of blasting technology is necessary in this mine.Based on the analysis of the mechanism of hole-by-hole blasting and factors affecting blasting effect,and according to the geological conditions of the mine,such blasting parameters as toe burden,hole-pattern parameters,subdrilling and delay time interval were optimized.The results of blasting experiment with the optimized blasting parameters showed that boulder yield was reduced to zero,for hard rock mass being difficult to be blasted the boulder yield was reduced to less than 2.5%,the blasting fragmentation sizewas uniform,the blasting quality was obviously improved.