Acoustic Emission and Fractal Precursory Characteristics of Coals with Different Bursting Liabilities in Loading Failure Process

Table 4

AE characteristics of different coal samples.

Bursting liability type of coal	Peak stress value (MPa)	AE precursor position	AE energy rate in main rupture point	Duration of postpeak failure stage (s)
Strong	26.9	During 85∼90% stress level to peak strength	353157	2
Weak	7.4	During 75∼78% stress level to peak strength	196605	92
No	4.1	During 51∼55% stress level to peak strength	63456	113