Stability Analysis of “Support-Surrounding Rock” System for Fully Mechanized Longwall Mining in Steeply Dipping Coal Seams

Table 1

The proportions of similar materials.

Layer	Thickness (m)	Thickness of model (cm)	Proportion (Sand: putty powder: gypsum)
Main roof	17	85	846
Immediate roof	2.32	16	828
Coal seam	5	25.0	20 : 1 : 3 : 15
Immediate floor	17.06	34	846
Main floor	9.0	45	837