BLASTING METHOD FOR V-CUT IN PROGRESSING TYPE BY STEP

摘要

PURPOSE: A blasting method for V-cut in a progressing type per step is provided to improve blasting efficiency by improving punching pattern while forming a center cut. CONSTITUTION: Main cut-holes(110,110a) are punched for over 1.6m in symmetrical shape while being inclined for 70 degrees from the vertical line of a free surface(100) in a blind end of a mine. Herein, punching ends(112,112a) are formed on a single line while being located apart from each other for 20cm. Auxiliary cut-holes(120,120a) are formed between the main cut-holes with the same angle as the main cut-holes. Herein, the punching length of the auxiliary cut-hole is shorter than the main cut-hole while forming the distance between punching ends(122,122a) of the auxiliary cut-holes for 20cm. Herein, a vertical cut-hole(130) is vertically punched between the auxiliary cut-holes for having a punching end(132) deeper than the punching ends of the main cut-holes for 20cm. Therefore, the breakage on the punching ends of the main cut-holes is prevented.