pillar-and-stall system

pillar-and-stall system

[′pil·ər ən ′stȯl ‚sis·təm]
(mining engineering)
A system of working coal and other minerals where the first stage of excavation is accomplished with the roof sustained by coal or ore.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.