Analysis and Application on Controlling Thick Hard Roof Caving with Deep-Hole Position Presplitting Blasting

Table 8

Technical parameters of presplitting blast holes.

Parameters	Unit	Primary blast presplitting						Periodic blast presplitting						Auxiliary blasting
		A1	B1	A2	B2	A3	B3	C1	D1	C2	D2	C3	D3	E1	E2
Length	m	39.2		38.7		34.5		39.2		38.9		35.1		15.7	15.8
Horizontal angle	°	0						0		3		7		0	0
Elevation angle	°	23	16	31	24	39	32	23	16	31	24	39	32	90	81
Sealing length	m	13.2		13.2		11.5		13.2		13.4		11.6		5.2	5.3
Cement slug/Stemming	m	3.2/10.0		3.2/10.0		3.0/8.5		3.2/10.0		3.5/9.5		2.7/9.0		1.2/4.0	1.3/4.0
Charge length	m	26.0		25.5		23.0		26.0		25.5		23.5		10.5	10.5
Charge weight	kg	31.2		30.6		27.6		31.2		30.6		28.2		12.6	12.6

Tips: the single cartridge length is 0.5 m and the charge weight is 0.6 kg.