Study on the Characteristics of Top-Coal Caving and Optimization of Recovery Ratio in Steeply Inclined Residual High Sectional Coal Pillar

Table 1

Coal and rock mechanical parameters.

Lithology	Bulk modulus (GPa)	Shear modulus (GPa)	Cohesion (MPa)	Tensile strength (MPa)	Internal friction angle (°)	Density (kg/m^3)
Siltstone	7.89	5.27	3.6	2.39	37	2768
Medium sandstone	5.72	4.33	3.5	2.87	35	2660
Carbon mudstone	2.13	1.09	2.8	1.23	32	2250
B3-6 coal seams	1.98	0.97	2.5	1.12	30	1270
Coal gangue	0.80	0.27	0.50	38.0	0.31	2000