What is"hydraulic washing" or "gravity separation"?explain with diagram

Gravity separation is a process of concentration of ore in which gangue(impurity) is separated from desired metal ore on the basis of their specific gravity. Generally water is used as medium therefore sometime called as hydraulic washing.

The machine used is known as Jig separator. After entering the jig separator, mixtures are treated by water and gradually come into several layers, the light minerals float up to the upper layer and heavy minerals precipitate down to the bottom layer of the sorting slots, then the minerals are discharged from the jig separator through the discharge device.