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Short screw type jacks on steel pins are used for face timbering at Arkwright mine, Morgantown, W Va; 7 ft of Pittsburgh seam is mined, leaving about 8 to 12 in. of roof coal; immediately above roof coal is 1 to 3 ft of drawslate; and above that is 8 to 12 in. of " wild" coal and 2 ft of fire clay; pins in rib holes made by drilling crew serve as rests for screw jacks supporting crossbars at face; timbering and clean up and timber cost cut.
Short screw type jacks on steel pins are used for face timbering at Arkwright mine, Morgantown, W Va; 7 ft of Pittsburgh seam is mined, leaving about 8 to 12 in. of roof coal; immediately above roof coal is 1 to 3 ft of drawslate; and above that is 8 to 12 in. of " wild" coal and 2 ft of fire clay; pins in rib holes made by drilling crew serve as rests for screw jacks supporting crossbars at face; timbering and clean up and timber cost cut.
Pins and jacks
Coal Age
Brooks, F.H. (author)
Coal Age ; 52
1947
2 pages
Article (Journal)
English
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