Construction and Application of Mathematical Model of Stable Fracture Development Zone of Roof

Table 2

Calculation results of ordinary high-level drilling.

Solution drilling	Lag effective angle (°)	(m)	(m)	(m)
5^#, 10^#	32.20	28.26	23.10	15.53
5^#, 15^#	33.46	27.82	21.56	15.34