A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Immediate roof should be strong but friable enough to break up and fill void quickly as supports are advanced; roof action is more uniform with overburden depths of 1000 ft or more -- and more erratic with lesser depths; strata cleavage planes may seriously affect roof control if roof member is thick, homogenous mass; critical period in roof control usually occurs when new face has retreated some 300 to 400 ft; most roofs will sag and begin to fail during first 100 ft of retreat; falls start at barrier and eventually work their way to face.
Immediate roof should be strong but friable enough to break up and fill void quickly as supports are advanced; roof action is more uniform with overburden depths of 1000 ft or more -- and more erratic with lesser depths; strata cleavage planes may seriously affect roof control if roof member is thick, homogenous mass; critical period in roof control usually occurs when new face has retreated some 300 to 400 ft; most roofs will sag and begin to fail during first 100 ft of retreat; falls start at barrier and eventually work their way to face.
Roof action with longwall
Coal Age
Carman, C.O. (author)
Coal Age ; 69
1964
3 pages
Article (Journal)
English
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