Key Blasting Parameters for Deep-Hole Excavation in an Underground Tunnel of Phosphorite Mine

Table 2

Explosion parameters of the four-hole slotting scheme.

Gun hole name	Parameter
	Number of holes	Single hole charge (kg)	Detonator section
Slot hole	10 (12, 7∼4)	3	MS1
Auxiliary hole	18 (15∼32)	2.5	HS6
Peripheral hole	15 (33∼47)	2.1	HS10

Nos. 3–6 are large empty holes. The detonator segments 1-2, 7-8, and 9–14 are, respectively, MS1, MS9, and HS2. The detonator segments from 15 to 18 are HS3, 19 to 22 are HS5, 23 to 26 are HS6, 27 to 29 are HS7, and 30 to 32 are HS8. The detonator segments of 33∼43 are HS9, while those of 44∼47 are HS10.