In longwall mining subsidence phenomenon, the "angle of break" is the angle between
A. The vertical line at the panel edge and line connecting the panel edge and zero subsidence on the surface
B. The vertical line at the panel edge and line connecting the panel edge and point of critical deformation on the surface
C. The vertical line at the panel edge and line connecting the panel edge and point of the maximum tensile strain on the surface
D. The horizontal line and the line connecting the panel edge and zero subsidence on the surface
Answer: Option A
This Question Belongs to Mining Engineering >> Introduction To Mining Engineering
A. Normal distribution
B. Skewed distribution
C. Lognormal distribution
D. Poisson distribution
A. 3 level heading district
B. 4 level heading district
C. 5 level heading district
D. 6 level heading district
It is very difficult to control shaley roof if coal is not left with the shale why?
A. It is weak in nature
B. It has weathering effect
C. It has great affinity to absorb moisture and get departed from immediate roof
D. It reacts with coaly surface
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