At a time when the mining industry across the globe are facing the challenge of environmental protection and conservation of resources, Sukinda Chromite Mine (SCM) of Tata Steel, have adopted an organic method to tackle the Hexavalent Chromium problem. This method is being used to remove toxic hexavalent chromium from chromite concentrates.

To produce Eco-friendly chromite concentrates, the Company has made use of an alternative technology for converting toxic hexavalent chromium to non-toxic trivalent chromium at its chromite mine in Sukinda.

The alternative technology has been developed in collaboration with the Central Leather Research Institute (CLRI), Chennai. It seeks to reduce the hexavalent chromium to trace levels (less than 0.01 ppm) in concentrates by using an organic reductant known as Terminalia Chebula.

The water coming from mines is fed to the Effluent treatment plant (ETP) through open channels. The treatment system consists of automatic dosing of a Ferrous Sulphate solution by gravity, kept in two 5000 KL PVC tanks, for the reduction of hexavalent chromium to trivalent chromium.

Since the chromium presence in the hexavalent state, in any industrial operation is environmentally unfriendly, the organic method for removing hexavalent chromium from chromite concentrates is considered significant.

Apart from being environment friendly, the organic reduction method saves a huge quantity of water compared to conventional methods of treatment of the Hexavalent chromium which requires huge (~200lit/tonne) amount of water.

Tata Steel was the pioneer in finding out a suitable method of treating hexavalent chromium by engaging Nagpur based National Environmental Engineering Research Institute (NEERI). Based on its findings, an Effluent Treatment Plant was set up in 1993. It used pickle liquor as the reagent for treatment, which was first of its kind in the country.

As an endeavour towards a better environment, a pilot plant was established in 1998 to introduce automation in the dosing system and removal of suspended solids from the mine water. After a successful trial of the pilot plant, a full-fledged effluent treatment plant with latest technologies of automatic dosing and suspended solid removal mechanism was established in 2002.

This has ensured that the water quality meets all the parameters prescribed by statutory authorities. The hexavalent chromium reduction is monitored in every hour and accordingly dose of ferrous sulphate solution is controlled to ensure that no hexavalent chromium goes with water.

Further, to take care of surface run-off, two more ETPs have been made operational at the lease boundary with Ferrous Sulphate solution treatment facility and settling pits, to remove hexavalent chromium and suspended solids.