首页 > Term: breast-and-pillar
breast-and-pillar
Pennsylvania. A system of working anthracite coal by bords 10 yd (9.1 m) in width, with narrow pillars 5 yd (4.6 m) wide between them, holed through at certain intervals. The breasts are worked from the dip to the rise.
- 词性: noun
- 行业/领域: 采矿
- 类别 一般矿业; Mineral mining
- Government Agency: USBM
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创建者
- ed.young
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(Milwaukee, United States)