采空区边坡
The Slopes of Empty Mine Area
采空区残煤
liptobiolite coal in goaf
采空区处理
gob treatment
Mined-out area disposal
goaf management
Mined-out area treatment
Abandoned stope treatment
goaf disposal
disposal of emptied stope
采空区地面塌陷
picks depletion region fall of ground
采空区加固处理
Consolidation treatment to over-mined zone