Mechanism of Roof Shock in Longwall Coal Mining under Surface Gully

Table 2

The mix proportion of simulated materials.

Lithology	Sand; /kg	CaCO3; /kg	Gypsum; /kg	Water; /kg	Sawdust; /kg
Loess	95.8	6.8	6.8	18.8	3.4
Mudstone	44.6	5.2	2.2	6.5	/
Fine sandstone	105.8	10.6	10.6	15.9	/
Sandy mudstone	160.4	22.5	9.6	24.1	/
Fine sandstone	175.3	40.9	17.5	33.4	/
Sandy mudstone	159.6	22.3	9.6	23.9	/
Fine sandstone	356.7	59.4	59.4	67.9	/
Sandy mudstone	53.1	7.4	3.2	8.0	/
Fine sandstone	153.0	25.5	25.5	29.1	/
Sandy mudstone	10.6	1.5	0.6	1.6	/
Coal	138.1	19.3	8.3	20.7	/
Siltstone	76.5	12.8	12.8	14.6	/