Study on Roof Breakage-Induced Roadway Coal Burst in an Extrathick Steeply Inclined Coal Seam

Table 4

Relation between the VG value and the coal burst hazard level.

Coal burst risk index	Risk level	VG anomaly (km/s^2)
0	None	<0.05
1	Weak	0.05∼0.15
2	Moderate	0.15∼0.25
3	Strong	>0.25