Chock is errected in between four corner props are generally not necessary except
A. Where the roof is bad
B. At goaf edges of gallaries
C. At junctions of gallaries
D. If the floor is sleeper 1 in 5
E. All these
Answer: Option E
A. Where the roof is bad
B. At goaf edges of gallaries
C. At junctions of gallaries
D. If the floor is sleeper 1 in 5
E. All these
Answer: Option E
The minimum length of sleeper used as chock support of the roof height to be supported excess of 3m.
A. 1.2 m
B. 1.5 m
C. 1.6 m
D. 1 m
The preferred shape of an opening in uniaxial stress field as
A. Circle
B. Ellipse
C. Ellipse with proper axis ratio
D. Ovaloid
Most of the Gondwana coals from any field are rich in . . . . . . . .
A. Durain
B. Fusain
C. Vitrain
D. Clairain
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