Study on Surrounding Rock Structure Evolution Characteristics and Roof Control Techniques of the Retained Roadway Formed by Roof Cutting in Inclined Coal Seams

Table 1

Temperature and wildlife count in the three areas covered by the study.

Lithology	Density (kg/m^3)	Bulk modulus (GPa)	Tensile strength (MPa)	Shear modulus (GPa)	Friction angle (°)	Cohesion (MPa)
Pelitic siltstone	2460	6.81	2.90	4.45	25	0.90
Siltstone	2750	8.50	4.30	6.65	30	2.30
Silty mudstone	2600	7.80	3.50	5.10	35	1.50
Coal	1300	2.80	0.40	2.58	24	0.68