Table 1. Mechanical Properties of Coal Seam and Rock.

lithology	thickness/m	density/(kg m–3)	bulk modulus/GPa	shear modulus/GPa	cohesion/MPa	tensile strength/MPa	internal friction angle/(°)
sandy mudstone	5	2500	66.62	26.35	18	3.8	39
fine sandstone	2	2700	78.84	24.44	25	3.2	43
aluminum mudstone	5	2500	70.62	28.35	16	3.8	37
sandy mudstone	8	2500	66.62	26.35	18	3.8	34
siltstone	7	2355	70.92	26.55	14	3.8	39
sandy mudstone	4	2500	66.62	26.35	16	3.1	34
mudstone	3	2250	54.39	22.27	19	3.8	30
siltstone	6	2700	78.84	24.44	25	3.2	41
fine sandstone	6	2355	62.92	26.55	1.04	1.1	27
coal	2	1450	10.55	10.54	0.8	0.8	16
siltstone	4	2355	62.92	26.55	1.24	1.1	35
fine sandstone	8	2700	78.84	24.44	25	1.2	41
fault		2000	2	2	0.5	0	18