Environment Minister Peter Garrett should be prepared for a radioactive headache at the next election if he gives BHP a blank cheque for its Roxby expansion, warn the Australian Greens.

The Greens Spokesperson for Nuclear Issues, Senator Scott Ludlam is travelling to Adelaide tomorrow (Friday May 1) for the release of the project's Environmental Impact Statement.

The project cannot go ahead without South Australian Government and Federal Government approval.

"If approved this mine will be the largest open cut mine in the world. One million tonnes of rock will be removed every day for four years, just to access the ore body and start producing revenue. The mine will pump through an additional 120 million litres of water per day and potentially increase the burden on South Australia's electricity supply by up to 25%, boosting the state's total green house gas emissions by 10-12%"said Senator Ludlam.

"Even more staggering is the mine's use of diesel. It will consume up to a 1 million litres a day and BHP will still be eligible for the Government's diesel subsidy for 18.5c a litre. It's a sad irony that a government that says it wants to take action on climate change will be paying one of the largest polluters in the world $65 million a year to guzzle mammoth amounts of diesel. When the price of the diesel soars again, this company will face some real obstacles to their mining plan."

"The project will leave South Australia with a permanent, toxic landmark - a 20 cubic kilometre pile of waste rock and tailings and an 8 billion cubic metre tailings dam."

"The Government's likely to talk up the potential for new job creation, but not all of the jobs associated with this project will be created on shore. The processing of bulk radioactive copper concentrate will happen in China, exporting skills, jobs, incomes and control over our uranium safety standards off shore."

Environment Minister Peter Garrett is expected to have final say on the expansion mid next year.

"Given his history as an anti-uranium campaigner, I expect Minister Garrett to give this project the scrutiny it deserves. If he doesn't, he risks creating a radioactive headache for the Government in an election year," concluded Senator Ludlam.