Abstract: Macrostructure parameter pillarless sublevel caving has been adopted in mining of Beiminghe iron ore, while problem of bad blast effects always exist in production, main present as high boulder yield, high accident rate of pushing-wall and hanging arch, and low recovery rate of single-row ore. After the study, little furnace hole angle, dense blasthole, narrow ore drawing port are the main reason to the above problems. Double rock drilling center experiment plan with 57°furnace hole angle was proposed and industrial experimental was done, better effects was obtained on blast effects improving and enhance ore recovery rate.

Key words: Pillarless sublevel caving, Recovery rate, Furnace hole angle, Ore drawing port