Mine rehabilitation plans for the proposed giant Carmichael coal mine fall far short of best practice and will expose the environment and taxpayers to huge risks, according to anti-mine group Lock the Gate.
On its submitted plans, the $16 billion-plus mine would disturb some 280 square kilometres of land, with 1.85 billion tonnes of potentially acid-forming material unearthed, and six giant voids left unfilled, Lock the Gate said in a new report. Some 88 kilometres of streams would also be disrupted and not restored.
"This is a monumental experiment on altering a landscape to a scale we've never seen before and believing a company that is saying already it doesn't think it can put it back to remotely close to what was there before," said Rick Humphries, co-ordinator of the group's mine rehabilitation reform campaign.
"We are asking them to be shifted from a low-end, minimalist cheapest [rehab] option to leading practice," said Mr Humphries, an environmental scientist who previously helped Rio Tinto develop their rehab plans.
The federal and state governments are backing the giant mine, which could produce as much as 60 million tonnes of coal for export a year. Carmichael's development could also help open up other coal mines in the Galilee Basin.
A report last week by the NSW Auditor-General found that state's mine rehabilitation guarantees held by the government to be inadequate and requirements for restoring land after a mine's closure to be vague. The state's rules, though, were superior to those in Queensland and Victoria, it said.
A spokesman for the Indian-owned company said assertions by Lock the Gate "are wrong which is consistent with previous claims by activists".
"Carmichael is the most intently and rigorously licensed and tested mining project by scientists and courts, not activists," he said. "The entire project has more environmental conditions than any other mine."
According to Lock the Gate, Adani wouldn't have to begin rehabilitation work until 39 years into its operations, well shy of the "continuous" rehab work that is considered best practice.
"The framework meets and exceeds industry guidelines," the Adani spokesman said, adding a "range of activities" would take place "across the full life of the mine".
The Queensland government itself is seeking to tighten the demands on mines - both existing and future - that it says will apply to Carmichael.
"The changes we have proposed to financial assurance and rehabilitation will apply to new and existing mine operations," said Steven Miles, Queensland's Environment Minister, noting Adani is yet to submit its plan of operations.
"For the first time mines will be expected to progressively rehabilitate as land becomes available for rehab, and their performance will be audited and publicly reported," he told Fairfax Media. "These next generation laws will ensure taxpayers are no longer left to foot the bill for failed mines or stranded assets."
Gavin Mudd, an associate professor of environmental engineering at RMIT University, said the rehab issues around Carmichael were "not necessarily Adani's fault" given the lax practice across Australia.
The sheer scale of the mine - about four times bigger than the largest coal mine now in Queensland - means the scope of issues, from disrupted ground and surface water to contaminated soil, continues to get larger, he said.
"You have to supersize your risk management but the industry doesn't want to go near a lot of that," Professor Mudd said.
Adani may be offered as much as $1 billion in loans from the federal government to help build the rail link from the mine to the coast. Its board still aims to give its final investment decision in the next few weeks, the spokesman said.
Financial closure would then be sought by the end of the year, and pre-construction works starting by the September quarter, he said.