Case Studies of Comprehensive Gas Control Method during Fully Mechanized Caving of Low-Permeability Ultrathick Coal Seams

Table 3

Detailed borehole parameters.

Location	Number	Dip angle, °	Diameter, mm	Length, m	Height of the orifice from the floor of roadway, m
Tailgate	1	12	75	11	1.5
	2	0	75	17	1.0
	3	-11	75	34	0.5
Headgate	4	30	75	60	1.5
	5	34	75	35	1.8
	6	43	75	19	2.1