A coal bed with a methane content is greater than . . . . . . . . m3/te. has been considered coal and gas out burst prone.
A. 2
B. 5
C. 9
D. 15
Answer: Option C
A. 2
B. 5
C. 9
D. 15
Answer: Option C
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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