Meaning of longwall

long•wall

Pronunciation: (lông'wôl", long'-), [key]
— adj. Mining.
  1. noting or pertaining to a means of extracting coal or other minerals in an underground mine from a continuous face, the roof before the face being supported at intervals by temporary or movable artificial supports. Cf. room-and-pillar.
—n.
  1. the continuous face so worked.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.