roof - safe
- roof sagging
- roof scaling
- roof shift
- roof stability
- roof stone
- roof strata
- roof subsidence
- roof support
- roof support for steep coal seams
- roof survey plug
- roof timber
- roof variability
- roof weight
- roof-bolt head
- roof-bolt hole
- roof-bolt setting
- roof-bolter
- roof-bolting drilling-and-setting machine
- roof-bolting machine
- roof-caving
- roof-lowering onto chocks
- roofbolt
- roofbolter swing cylinder
- roofbolting
- room
- room depth
- room fender
- room mining
- room neck
- room work
- room-and pillar mining
- room-and-pillar caving
- room-and-pillar method
- room-and-pillar mining
- room-and-pillar system
- room-and-pillar with filling
- room-and-pillar without extraction of pillars
- room-and-rance
- room-and-stoop
- room-work
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