(i) Hydraulic Washing: in this procedure, the ore is first powdered. A stream of water running in an upward direction is now used to wash the ore which was powdered earlier. The heavy ore particles remain after the washing, whereas the gangue particles are washed away.
(ii) Magnetic Separation: This method can be employed if either the ore or the gangue particles are attracted by a magnetic field. In this method, the ore is finely powdered and placed on a conveyer belt which is moved over a magnetic roller. The particles which are not attracted by the magnetic field fall off the conveyer belt.
(iii) Froth Floatation: this procedure is generally used in the removal of gangue in sulfide ores. The ore is powdered and made to form a suspension with water. Now, collectors such as fatty acids and pine oils are added along with froth stabilizers. The mineral particles are wet by oils whereas the gangue particles are wet by water. The froth is now skimmed off and dried in order to recover the ore.