Study on Occurrence Mechanism of Coal Pillar in L-Shaped Zone during Fully Mechanized Mining Period and Prevention Technology

Table 1

The critical index values of burst potentiality about coal seam.

Burst potentiality testing indexes				Burst potentiality degree	Classification
DT/ms		KE	RC (MPa)
DT > 500	< 2	KE < 1.5	RC < 7	No	I
50 < DT ≤ 500	2 ≤  < 5	1.5≤ KE < 5	7 ≤ RC < 14	Weak	II
DT ≤ 50	≥ 5	KE ≥ 5	RC ≥ 14	Strong	III