Copper concentrate, apart from copper, contains traces of gold & silver. The gold & silver thus present is extracted during electrolysis (final stage of copper extraction cycle) in the form of black powder called Anode Slime. Typical gold & silver content in slime are 2% & 12% respectively. Presently Sterlite Industries (India) Ltd. (SIIL) does not have refining facility to treat or refine Anode slime. The slime is being exported to European & other refineries.