Coal mine operations are prohibited if the depth of cover is less than
A. 15 m
B. 20 m
C. 25 m
D. 30 m
Answer: Option A
A. 15 m
B. 20 m
C. 25 m
D. 30 m
Answer: Option A
The required water for 1 ton of sand in hydraulic sand stowing is . . . . . . . .
A. 800 l
B. 600 l
C. 1100 l
D. 1200 l
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