BHP Billiton's Olympic Dam project, set to be the world's biggest mine, could have a second life as an outback tourist attraction when it closes.
As well as a giant open pit, the company will leave behind a small mountain of unused rocks and a large tailings storage facility which will need to be fenced off with warnings of the potential for radiation exposure. Once mining stops in South Australia's north, the pit is expected to fill with rising groundwater, creating a vast outback lake that would be up to 350 metres deep.
BHP Billiton says backfilling is not a feasible option and has suggested the SA government resume control of the pit and turn it into a managed tourist attraction.
It says the government would be responsible for building and maintaining viewing platforms and controlling access by tourists, students and scientists.
It suggests the rock storage, where it will dump the "overburden" of surface rock and soil which will take about five years to remove, should be returned as crown land and could also be used for tourism.
The company says its metallurgical plant, where it will process copper ore, could become a research and education facility.
BHP Billiton's closure and rehabilitation plans for the Olympic Dam site are outlined in the SA government's development assessment for the company's $30 billion expansion of its existing underground operations.
The project was approved by the state and federal governments yesterday.
The expanded mine is planned to be productive for 40 years, although estimates suggest the ore body could offer a 100-year supply of copper and uranium.
Over the next four decades the open pit will grow to be more than 4km long, 3.5km wide and 1km deep.
The mine will produce about 750,000 tonnes of copper and about 19,000 tonnes of uranium oxide a year.
The state government has imposed 150 conditions to address environmental and other concerns, including the impact on air quality, increased greenhouse gas emissions, groundwater supplies, local communities, wildlife and the marine environment around a planned desalination plant.
Anti-nuclear groups and the Greens have criticised the conditions for not going far enough, but are equally concerned about what will be left behind.
The Australian Nuclear Free Alliance said almost nine billion tonnes of radioactive waste would remain in the SA outback.
A spokeswoman said if that was acceptable to the state government, then it was setting the bar "extremely low".
"The radioactive waste will remain on Kokatha and Arabunna country long after BHP Billiton packs up its business and moves on," she said, referring to traditional indigenous landowners of the region.
But SA's peak mining group said the mine would bring huge economic benefits to South Australia, regional communities and the nation.
"In addition to the huge income stream brought to our state and the nation through taxes and royalties once the expansion is operational, the indirect benefits created will be phenomenal," SA Chamber of Mines and Energy chief Jason Kuchel said.