Control of the Chamber in Extra-Thick Coal Seam Based on Fracture Characteristics of Coal Rock and Mass

Table 5

Mechanical parameters of the rock at Tashan Coal Mine.

Lithology	Intact rock		RQD	Rock mass
	E (GPa)	σc (MPa)		Em (GPa)	σcm (MPa)	σtm (MPa)
Medium sandstone	45.5	69.4	90	26.4	47.4	4.7
Sandstone	36.2	23.6	89	20.1	15.7	1.6
Mudstone	15.8	17.4	57	2.2	4.4	0.4
3–5# coal seam	6.8	13.2	65	1.4	4.2	0.4
Mudstone	15.2	7.2	63	2.8	2.2	0.2
Coarse sandstone	35.1	75.6	91	21.3	53.3	5.3