Process : In this process, the powdered sulphide ore is mixed with water & pine oil. The whole mixture is then stirred vigorously by passing compressed air. The oil forms a froth with air bubbles. The sulphide ore particles get attached with the Froth & Floats on the surface, while the gangue or earthy impurities are wetted by water & sink to the bottom of the tank. The floating froth is then skimmed off into settling basins.