Table 4: Properties of the intact rock mass.

LithologyRQDEr (GPa)Em (GPa)σr (MPa)σm (MPa)

Mudstone 1604.60.815.75.0
Gritstone 15610.01.438.110.8
Mudstone 2354.60.319.13.1
Number 9 coal313.20.211.71.7
Mudstone 3414.60.519.13.6
Medium-fine sandstone7013.03.236.315.0
Gritstone 2769.02.936.617.8
Mudstone 4804.61.717.49.4
Number 11 coal823.21.311.76.7