홈 > Term: underearth
underearth
A hard fireclay forming the floor of a coal seam. See: underclay.
- 품사: noun
- 분야/도메인: 광업
- 카테고리: 일반 광산; Mineral mining
- Government Agency: USBM
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작성자
- ed.young
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(Milwaukee, United States)
