A General Review on Longwall Mining-Induced Fractures in Near-Face Regions

Table 1

Parameters for predicting the height of the caved zone .

Rock type	UCS (MPa)	Representative strata lithology	Parameters
			Hard and strong	>40	Quartz sandstone, limestone, sandy shale, conglomerate	2.1	16	2.5
Medium hard	20–40	Sandstone, argillaceous limestone, sandy shale, shale	4.7	19	2.2
Soft and weak	10–20	Mudstone, argillaceous sandstone	6.2	32	1.5
Weathered soft and weak	<10	Bauxite rock, weathered mudstone, clay, sandy clay	7.0	63	1.2