Dr Garnaut, who recently visited Port Moresby for climate change talks, reluctantly spoke to the ABC about the issue.
But as the chairman of PNG Sustainable and a board member of Ok Tedi, is it OK to let that amount of waste to go down the river?
ROSS GARNAUT, CHAIRMAN, PNG SUSTAINABLE: You would not believe the amount of effort that's gone into carefully managing that including the investment of $400 million in a project to remove the toxic sulphur from the project, including the commissioning of first one dredge, then a second dredge to remove material from the river. It's the most thorough and careful management of the environment that's ever been undertaken by a mining company. Thanks very much.
STEVE MARSHALL: But a management decision has let a huge amount of waste go down the river, Doctor.
ROSS GARNAUT: I do, I do, I do have to get back to climate change. That's what I'm here for today. There's are lot of people waiting for me at another place. So, very nice to see you, Steven. Goodbye.
PETER FACKLER: To remove the dredge out of the river system is totally against their operating conditions.
STEVE MARSHALL: Until two months ago, Peter Fackler was an Ok Tedi supervisor at the Bige dredging site. He was alarmed at the decision to remove the dredge.
PETER FACKLER: So that means that there's been a slug of around 20 million cubic metres that's working its way down the Ok Tedi River as we speak.
STEVE MARSHALL: Twenty million cubic metres of mining waste, enough to fill the Melbourne cricket ground 12 times over. Ok Tedi's website claims the company removes 15 million cubic metres of waste from the river each year, but this internal email reveals that the dredge removed just three million cubic metres of waste over an 18-month period.
http://www.abc.net.au/7.30/content/2008/s2451559.htm