The collapse of roof in the goaf which is delibarately brought about by withdrawal of roof supports called
A. Normal Collapse
B. Premature collapse
C. Roof fall
D. Burst
Answer: Option A
A. Normal Collapse
B. Premature collapse
C. Roof fall
D. Burst
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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