The contribution of tertiary coal is about, what percent of the country coal resources is about.
A. 4%
B. 6%
C. 1%
D. 7%
Answer: Option C
A. 4%
B. 6%
C. 1%
D. 7%
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
Join The Discussion