APPLICATION OF STAGED BURN-CUT IN SHAFT BLASTING IN LIMESTONE
分层分段直眼掏槽在石灰岩井筒爆破中的应用研究

Field experiments of vertical staged cutting with a duplex-triangle, with a duplex-square, and with millisecond delay in a hole are reported in this paper. It is found that the staged cut with duplex-square has the best blasting effect in trial shafts sinking. This experimental result is analyzed with the existing achievements of rock dynamics. In addition, our experiments also indicate that the best depth of blast hole is close to shaft radius.