Ventilation door must be arranged to close automatically and with this object frame of the door is so fitted that the top leans about forward in the direction of air pressure.

Which of the following prime characteristic the nonel blasting has?

A. It has greater shock to the surrounding

B. It is noiseless in character

C. It has tremendous effect on explosive column

D. It can not be used in a place where there is a chance of stray current

The main purpose of self rescuer is to enable the wearer to escape through an atmosphere resulting after a . . . . . . . . or after an . . . . . . . . in a mine.

A. Fire, Explosion

B. Gas, Outburt

C. Rockburst, bump

D. None

Cyclone, bag filter and scrubber can be used for control.

A. Water pollution

B. Soil pollution

C. Air pollution

D. Noise pollution

A two phase system in which an inner or dispersed phase is distributed in an outer called

A. Emulsion

B. Slurry

C. Explosion

D. Erosion