홈 > Term: guardian angel
guardian angel
A warning device affixed to the roof or back of a mine that automatically displays a visual indication when rock displacement begins.
- 품사: noun
- 분야/도메인: 광업
- 카테고리: 일반 광산; Mineral mining
- Government Agency: USBM
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작성자
- ed.young
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(V.I.P) 21084 포인트 - 100% positive feedback
(Milwaukee, United States)
