Drilling And Blasting - Study Mode
[#151] Maximum quantity of air leaks in a coal mine ventilation is at
Correct Answer
(B) Surface air lock
[#152] Gun powder having effect
Correct Answer
(B) Heaving
[#153] In a continuous miner face, why forcing ventilation undesirable.
Correct Answer
(C) Exposes workers to high concentrations of dust
[#154] The self heating of coal in underground mines the ratio CO/O 2 defficiency gradually . . . . . . . .
Correct Answer
(B) Increases
[#155] Blades of rotor of air screw fan, the angle or pitch can be varried by . . . . . . . .
Correct Answer
(B) 10° - 15°