Research on the Characteristics of Coal Bump and Monitoring and Early Warning in Hujiahe Coal Mine

Table 1

Geometry and mechanical parameters of coal and rock.

Rock properties	Thickness (m)	Modulus of elasticity (GPa)	Poisson ratio	Cohesive strength (MPa)	Internal friction angle (°)	Tensile strength (MPa)
Sand shale	60	6.10	0.12	4.5	27	1.76
Sandstone	60	6.36	0.14	3.23	25	3.90
Mud stone	60	1.86	0.13	5.67	32	1.54
Fine sandstone	12	6.34	0.11	6.21	29	2.79
Silt stone	5	2.32	0.10	5.13	25	1.92
Coal	23	0.81	0.02	5.43	20	2.13
Silt stone	100	2.46	0.11	2.45	31	1.63