Question

The process(es) by which lighter earthy particles are freed from the heavier particles using water is/are:

• A. Gravity separation
• B. Magnetic separation
• C. Hydraulic washing
• D. Leaching

Answer 1

Answer: (A), (C)

Hydraulic washing

Gravity separation method is based on differences​ in gravity of ore and gangue particles.
An upward​ stream of running water is used to​ wash the powdered ore where the lighter gangue particles are washed away and heavier ores are left behind.
This method is also know as gravity separation.
Hence, option (a) and (c) are correct.

Magnetic separation is used to separate magnetic impurities from non-magnetic ores.

Leaching is a chemical method for concentration of ore.