The reasonable hole pattern of deephole blasting was utilized to make fully use of the explosive energy to improve the crushed ratio to lower the boulder yield and to obtain better dam rocks.
The practice proves that given blasting technique can prominently raise the lump coal ratio and get a good economic benefit.
实践证明，文中所研究的爆破技术能较显著地提高块煤率，能取得较好的经济效益。
3
It is special important meaning that Deep - hole blasting With bottom Gap Charging is used to protect bottom rock from breaking, to decrease block ratio and to improve blasting efficiency.