A. Angle between two vertical lines of subsidence
B. Angle between vertical line and horizontal line
C. Angle between two limit lines
D. Angle between limit line of subsidence and vertical line of any side
Answer: Option D
This Question Belongs to Mining Engineering >> Mine Supports And Strata Control
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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