홈 > Term: drift and pillar
drift and pillar
N. Staff. A system of working coal similar to the room and pillar system.
- 품사: noun
- 분야/도메인: 광업
- 카테고리: 일반 광산; Mineral mining
- Government Agency: USBM
0
작성자
- ed.young
-
(V.I.P) 21084 포인트 - 100% positive feedback
(Milwaukee, United States)
