room-and-pillar [room-uh n-pil-er, roo m-] adjective Mining.
- noting a means of extracting coal or other minerals from underground deposits by first cutting out rooms, then robbing the pillars between them; pillar-and-breast.
Compare longwall.
room-and-pillar [room-uh n-pil-er, roo m-] adjective Mining.
Compare longwall.