The Sterlite copper smelting plant in Thoothukudi has indiscriminately dumped 5,37,765 tonnes of copper slag in various places including the banks of Uppar river, even though various research papers published by highly reputed international journals have confirmed that there is a huge adverse environmental impact due to the dumping of slag in the open, the State government has told the Madras High Court.
In a counter-affidavit to a public interest litigation petition by activist R. Fatima, insisting upon remediation, the government said copper slag was generated in the smelting process of the manufacturing of copper from its ore. During smelting, impurities in the raw material float on the molten metal. These impurities were collected and quenched in water, thereby producing angular granules called copper slag.
The slag was largely a stable solid waste and had been classified by the Central Pollution Control Board as a ‘high volume low effect’ waste. Studies in this regard had demonstrated that for slag to be used beneficially, it must be tested to determine its composition and, in case it meets certain parameters, it could be used for specific purposes such as laying roads, cement aggregate-making and abrasive production.
