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.
The government also stated that the copper slag was generated in the ratio of 1:2, which meant that two tonnes of slag would get generated for every tonne of copper anode manufactured. Sterlite plant had been granted consent to manufacture 1,200 tonnes of copper anode per day, and therefore, its daily generation of copper slag was 2,400 tonnes. The annual generation was around 7.92 lakh, considering the plant worked for 330 days in a year.
The huge generation of slag would cause considerable stress on disposal. Therefore, in 2012, the consent to operate the copper smelting plant was given on the condition to dispose of the copper slag for beneficial uses. However, during an inspection on March 10, 2017, 3.25 lakh tonnes of slag was found dumped along the Uppar Odai. Further, 11,250 tonnes was dumped in Silukanpatti village and 13,000 tonnes in the SIPCOT industrial complex itself.
Listing various other places where the slag had been dumped, the government said even a Division Bench of Justices T.S. Sivagnanam (now transferred to the Calcutta High Court) and V. Bhavani Subbaroyan had made adverse remarks against such dumping in their August 18, 2020 order upholding the permanent closure order issued against the plant. It also stated that till now, the company had not removed the dumped 5.37 lakh tonnes of copper slag.
The government said a reputed accredited agency should be engaged to evaluate the dump sites to ascertain whether they had been contaminated, and then undertake scientific remedial measures. Since the plant remained closed and an appeal against the Division Bench’s order was pending before the Supreme Court, a decision on assessing the contamination in and around the plant could be undertaken only after the result of the appeal, it added.
After taking the counter-affidavit on file, the first Bench, led by the Chief Justice, adjourned the case by two weeks, since senior counsel P.S. Raman, representing Vedanta Limited, which runs the copper smelting plant, sought time to file a rejoinder.
