Mine air should contain minimum . . . . . . . .% O2 in USA.
A. 17.5
B. 19
C. 19.5
D. 20
Answer: Option C
A. 17.5
B. 19
C. 19.5
D. 20
Answer: Option C
The mechanical mixture of gases existing in a mine given off after explosion called
A. White damp
B. Stink damp
C. Black damp
D. After damp
A Drager Gas Mask does not filter
A. Water vapour
B. Nitrous fumes
C. Carbon monoxide
D. Carbon dioxide
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