홈 > Term: dropping pillars and top coal
dropping pillars and top coal
(Australia) The second working, consisting of drawing the pillars, and in thick seams breaking down the upper portion of the seam that was left temporarily in position.
- 품사: noun
- 분야/도메인: 광업
- 카테고리: 일반 광산; Mineral mining
- Government Agency: USBM
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- ed.young
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