In scrubby bushland near the turn-off to the popular waterfalls of Litchfield National Park, a small metal sign is the only clue that something is not quite right.
"DO NOT ENTER. The land beyond this point has been declared a Restricted Use Area," it states.
This vast fenced-off area, 100 kilometres south of Darwin, was once the site of the Rum Jungle uranium mine, which supplied the United States and British nuclear programs during the Cold War.
But almost 50 years since it closed, Rum Jungle has left a legacy of environmental damage so severe that it will cost hundreds of millions of dollars to rehabilitate over the next decade.
Rum Jungle is just one of several old, disused mines in the Northern Territory, where taxpayers have been forced to foot multi-million-dollar bills to curtail their toxic aftermath.
But some fear they won't be the last of the so-called "legacy mines", after the Northern Territory government abandoned plans to tighten accountability laws for mining companies.
"Rum Jungle is just a signal of what we're looking down the barrel of here in the territory, in terms of legacy mines," Environment Centre NT co-director Kirsty Howey said.
'Chain of responsibility' laws promised
In 2021, the NT government announced it would introduce "chain of responsibility" laws to ensure that even if an entity responsible for environmental damage were to become financially insolvent, someone other than the taxpayer — such as a parent company or director — would be held to account.
But rather than limiting the proposed laws to petroleum companies — as recommended by a scientific inquiry into fracking — the government last year said the laws would apply to any activity capable of harming the environment, including the wider mining industry.
"It was a watershed event in the history of the Northern Territory's environmental regulation," Ms Howey said.
But 12 months on, the government's draft bill shows the proposed laws won't take in all mining operations, and would only apply to petroleum companies.
"To our great surprise … the territory government has backflipped on its promise to ensure that all mining activities would be subject to these important 'chain of responsibility' laws," Ms Howey said.
"It's unacceptable that the mining industry is being given a free pass here, while the gas industry has to ensure that it complies with this legislation."
The government's shift in policy has also raised the ire of the Northern Land Council, which says Aboriginal landholders have historically borne the brunt of mining pollution.
"The NLC urges the NT government to reconsider the approach taken in the draft legislation to ensure that environmental chain of responsibility laws apply to all industry sectors," its chief executive, Joe Martin-Jard, said.
"The proposed narrow application of (the) laws … only ensures the potential for future legacy mine sites remains high."
Mining industry says adequate laws already in place
Queensland introduced its own chain of responsibility laws in 2016 amid concerns that taxpayers could face an estimated $100 million clean-up bill if Clive Palmer's nickel refinery folded.
Victoria also has laws that allow environmental responsibilities to be transferred to associated entities.
But the Minerals Council of Australia (MCA), which represents the mining industry, said such laws are not needed in the Northern Territory because of existing accountability measures.
These include a requirement for mining companies to provide the government with security bonds that cover the estimated cost of rehabilitation.
A total of more than $1.6 billion in securities is currently held for 11 active mines in the territory.
Mining companies must also pay an annual one per cent levy on their securities, which goes into a separate fund to deal with legacy mines.
"You have to be really careful in a jurisdiction like the Northern Territory when we are looking for investment not to have legislation that is overreaching, or overburdensome," the MCA's executive director in northern Australia, Cathryn Tilmouth, said.
"Adding another piece of legislation like the chain of responsibility requirements, on top of what's already required for the heavily regulated mining industry, has the potential to cause concern to investors."
Government delivering 'significant' environmental law reform
The Northern Territory government said it was committed to implementing all recommendations of the scientific inquiry into fracking, as well as additional environmental reforms.
"The Territory Labor government is delivering the most significant reforms of the Northern Territory's environmental laws and regulations to ensure our environment is protected for our future generations," a spokesperson said.
"This includes significant regulatory reform underway in the mining industry."
Submissions on the draft bill closed last week.
It is unclear when the government will introduce the proposed legislation to parliament.
