The Properties of a Coal Body and Prediction of Compound Coal-Rock Dynamic Disasters

Table 1

Experimental results of coal bump proneness index under different gas pressure conditions.

Type name		1-type without gas	2-type gas pressure of 1 MPa	3-type gas pressure of 2 MPa
Bump proneness index	Dynamic fracture time (ms)	280	630	640
		260	480	460
		320	570	720
	Average	287	560	607
	Elastic energy index (EEI)	2.33	1.87	1.77
		3.21	1.76	1.52
		2.90	1.69	1.43
	Average	2.81	1.77	1.57
	Bump energy index (BEI)	1.92	1.62	1.23
		1.74	1.51	1.35
		1.81	1.38	1.56
	Average	1.82	1.50	1.41