홈 > Term: four-piece set
four-piece set
Squared timber frame used in underground driving to give all around support to weak ground. A cap is supported by two posts on a sill-piece or sill.
- 품사: noun
- 분야/도메인: 광업
- 카테고리: 일반 광산; Mineral mining
- Government Agency: USBM
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- ed.young
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