Surface Subsidence Control Mechanism and Effect Evaluation of Gangue-Backfilling Mining: A Case Study in China

Table 1

Strata simulation material ratio scheme in the physical model.

Lithology	Quality ratio; (sand : mica : cement)	Cement quality ratio; (gypsum : calcium carbonate)
The floor (fine sandstone)	71 : 13 : 16	7 : 3
Coal	80 : 17 : 3	7 : 3
Sandy mudstone interbed	71 : 23 : 6	3 : 7
Siltstone	79 : 16 : 5	5 : 5
Fine sandstone	74 : 16 : 10	5 : 5
Fine siltstone interbed	74 : 16 : 10	3 : 7
Weathered mudstone	73 : 23 : 4	5 : 5
Topsoil	80 : 18 : 2	3 : 7