Analytical Analysis and Field Observation of Break Line in the Main Roof over the Goaf Edge of Longwall Coal Mines

Table 2

Properties of coal and roof formation.

Lithology	UCS/(MPa)	GSI			/(GPa)	/(GPa)
Fine sandstone	165.3	64	14	0.7	27.73	14.55
Medium sandstone	146.2	66	16	0.7	28.14	16.327
Gritstone	162.4	72	17	0.7	32.66	23.06
Siltstone	142.3	70	16	0.7	30.73	20.55
Sandy mudstone	63.28	43	11	0.7	11.58	3.46
Coal seam	13.89	14	4	0.7	2.06	0.30
Mudstone	44.6	47	9	0.7	6.85	3.65