A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
In mine No 7 of Consolidated Coal Co at Staunton, Ill, immediate roof over coal seam is slate, from few inches to 7 or 8 ft thick; overlying rock is limestone, probably never less than 20 ft thick; theory of roof bolting; bolt is 1 in. diam, of length depending on thickness of slate; hole drilled through slate and 12 to 16 in. into limestone; special nut tightens expansion shell; short section of channel used as washer; in poor slate, channel spans two or more bolts. (see also Colliery Guardian v 177 n 4573 Sept 3 1948 p 325-6)
In mine No 7 of Consolidated Coal Co at Staunton, Ill, immediate roof over coal seam is slate, from few inches to 7 or 8 ft thick; overlying rock is limestone, probably never less than 20 ft thick; theory of roof bolting; bolt is 1 in. diam, of length depending on thickness of slate; hole drilled through slate and 12 to 16 in. into limestone; special nut tightens expansion shell; short section of channel used as washer; in poor slate, channel spans two or more bolts. (see also Colliery Guardian v 177 n 4573 Sept 3 1948 p 325-6)
Roof support with suspension rods
Min Congress J
Conway, C.C. (author)
1948
4 pages
Article (Journal)
English
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Roof support with suspension rods
| Engineering Index Backfile | 1948
| Engineering Index Backfile | 1949
| Engineering Index Backfile | 1949
| Engineering Index Backfile | 1949