Application and Development of an Environmentally Friendly Blast Hole Plug for Underground Coal Mines

Table 6

Drilling pattern and charge weight in return entry.

Hole name	Number	Hole depth (m)	Angle/°		Total charge (kg)	Firing sequence	Connection way	Filling way
			Horizontal	Vertical
Intermediate hole	1~4	2.7	90°		1.6 × 4	1	Series	Full filled
Intermediate hole	5	2.7	90°		0.6 × 1	2
Cut hole	6~11	2.5	83°	85°	1.6 × 6	2
Auxiliary hole	12~25	2.5	90°		1.6 × 14	3
Brukup borehole	26~45	2.5	90°		1.4 × 20	4
Trim hole	46~70	2.5	87°		0.6 × 25	5
Bottom hole	71~82	2.5	90°	85°	1.2 × 12	5
Total	82				96.4