Research on Formation Mechanism and Evolution Pattern of Bed Separation Zone during Repeated Mining in Multiple Coal Seams

Table 2

Physical and mechanical parameters of coal and rock mass.

No.	Lithology	Bulk density (KN/m^3)	(GPa)		(MPa)	(°)	Tensile strength (MPa)
6	Medium sandstone	25.42	13.25	0.17	10.63	34.00	4.00
5	Fine sandstone	24.79	16.45	0.18	12.55	31.00	4.65
4	Siltstone	24.89	9.09	0.30	9.11	41.00	6.40
3	Sandy mudstone	25.10	5.42	0.24	6.83	33.00	2.25
2	Mudstone	25.50	3.05	0.16	4.98	32.00	1.57
1	Limestone	24.00	5.53	0.21	3.63	38.00	2.06