NORSK Hydro's Kurri Kurri aluminium smelter had an environmental legacy in the form of up to half a million tonnes of spent potlining materials, people familiar with the plant said yesterday.
Hydro's closure announcement this week was based on "mothballing" the plant but the company has said it does not expect conditions to improve in the foreseeable future.
The main union at the site, the Australian Workers Union, is treating the closure as permanent, and officials met with federal MPs Greg Combet and Joel Fitzgibbon in Newcastle yesterday to discuss helping the workforce.
Hydro's 344 employees are covered by a redundancy package based on three weeks' pay for every year of service.
Olaf Wigstol, the Oslo-based Hydro vice-president who flew to Australia to oversee the closure of the Kurri plant, told the Newcastle Herald on Wednesday that the plant had been responsibly managed and there was no environmental legacy to speak of.
But like almost every aluminium smelter in the world, Kurri has a massive stockpile of spent potlining material.
Weston Aluminium, which was established in 1996 to process smelter dross, wants consent to treat up to 40,000 tonnes a year of "second cut spent potlining wastes".
Its environmental assessment says the carbon-based potliner has "the same dangerous goods classification as dross", containing cyanide, flouride and other contaminants.
Weston managing director Garbis Simonian said Hydro was a large multinational company that should be made to pay for the clean-up.
He said Weston's application followed four years of "successful" trials.
Kurri Kurri activist Col Maybury agreed with the need to treat the stockpile but said it should be done further away from people.
Mr Maybury said the 43-year-old smelter had produced 12,000 tonnes of spent potliner a year, meaning the stockpile was close to 500,000 tonnes.
Mr Simonian said it cost $650 a tonne to process the potliner. At this price, the potliner clean-up alone would cost $325 million.