Natural Frequency of Coal: Mathematical Model, Test, and Analysis on Influencing Factors

Table 2

Mechanical parameters of dried coal samples.

Type of coal	Elasticity modulus (GPa)	Poisson’s ratio	Uniaxial compressive strength (MPa)
Lignite	1.11	0.32	9.36
Bituminous	3.16	0.29	18.69
Anthracite	2.67	0.30	14.73