Investigation on the Movement and Fracture Characteristics of an Extra-Thick Hard Roof during Longwall Panel Extraction in the Yima Mining Area, China

Table 2

Parameters of the similar material.

Rock strata	Fine sand : gypsum : lime : water	UCS of similar material (MPa)	UCS of prototype rock (MPa)
Conglomerate rock	6.0 : 0.5 : 0.5 : 0.6	0.28	44.8
Mudstone	7.0 : 0.4 : 0.6 : 0.7	0.19	30.4
Sandstone	7.0 : 0.5 : 0.5 : 0.7	0.17	27.2
Coal seam	8.0 : 0.6 : 0.4 : 0.8	0.10	16.0
Siltstone	7.0 : 0.4 : 0.6 : 0.7	0.19	30.4