Mechanical Operations

A. Magnetic separation method can be employed to treat both dry & wet ores
B. Reduction ratio in crushing operation is defined as the ratio of minimum feed size to the
maximum product size
C. Gyratory crusher is used for coarse crushing
D. Screens are of stationary, moving and vibratory types

A. Increases
B. Decreases
C. Remain constant
D. None of these

A. 1
B. < 1
C. > 1
D. ∞

A. Roll crusher
B. Hammer crusher
C. Ball mill
D. Tube mill

A. Over-sizes are present in undersize fraction
B. Under-sizes are retained in oversize fraction
C. Screen is plugged with solid particles
D. Screen capacity is abruptly increased

A. Disks have very sharp edge
B. Solids are not deposited at the edge of the disk
C. Bulk of the solids are removed at the periphery of the disks
D. None of these

A. Gape is the greatest distance between the crushing surfaces or the jaws
B. The angle of nip (2α) is the angle between roll faces at the level where they will just take hold
of a particle and draw it in the crushing zone
C. Crushing efficiency is the ratio of the energy absorbed by the solid to the surfaces energy
created by crushing
D. Reduction ratio is the ratio of the maximum size of the particles in the feed to that in the
product

A. Jaw
B. Roll
C. Gyratory
D. None of these

A. Kozeny-Carman
B. Hagen-Poiseuille’s
C. Fanning’s
D. Kremser

A. Over cake
B. Over medium
C. Overall
D. None of these