The federal and Northern Territory governments have been accused of "secrecy" after being unwilling to say why they decided not to extend a lease to the Jabiluka uranium mine.
The mine is under lease to Energy Resources of Australia which also operates the adjacent defunct Ranger uranium mine next to Kakadu National Park, near Jabiru, 300km east of Darwin.
On Monday, the almost insolvent company looked to its biggest shareholders, including Rio Tinto and Packer & Co, for $210 million capital to continue the rehabilitation at Ranger, warning it would run out of money by Christmas.
ERA had been granted access to the Jabiluka area, an as-yet undeveloped uranium deposit south of Ranger that is estimated to hold 137,100 tonnes of uranium oxide.
About two weeks before the 42-year lease expired on August 11, then NT Labor Minister for Mining Mark Monaghan refused to extend it after receiving advice from Federal Labor Minister for Resources Madeleine King.
ERA has challenged this decision in the Federal Court.
In documents released by the Federal Court of Australia, ERA chief executive Brad Welsh criticised the federal government as being influenced by traditional owners and anti-uranium activists.
Mr Welsh's affidavit claims the prime minister met with former Labor environment and water minister Peter Garrett before meeting with his company.
ERA claims the advice given by Ms King was invalid because it denied the firm procedural fairness and the opportunity to be heard.
During a single 30-minute interview with representatives from ERA on June 28, Ms King did not identify any issues of concern regarding the mine and instead said the firm had "made good points," court documents claim.
This allegedly created the false impression no decision was imminent and that further consultation would take place.
Weeks before the Northern Territory election on August 24, Mr Monaghan announced the lease would not be renewed.
ERA also claims Ms King's advice was unreasonable because it failed to take into account its interests in Jabiluka and gave too much weight to federal government plans to extend Kakadu National Park into the area.
Mr Monaghan's decision not to renew the lease is also under attack as a jurisdictional error because it was based on advice that was invalid.
He also did not take into account ERA's compliance with the terms of the lease and territory laws which entitled it to a further 10 years on the lease, court documents say.
In court submissions made public on Tuesday, the uranium miner says it tried but failed to get a copy of the advice given by Ms King to Mr Monaghan.
"The secrecy with which the process has been attended since the advice decision is symptomatic and a continuation of the prior unfairness," the firm's barrister Richard Lancaster SC wrote.
The Jabiluka mineral lease has an estimated value of around $90 million.
An offer to buy the lease for $550 million by Boss Energy was withdrawn after Federal Minister for the Environment and Water Tanya Plibersek said in July the government intended to incorporate the site into Kakadu, Mr Welsh told the court in an affidavit.
In its 2023 annual report, ERA said there were no plans to develop the Jabiluka area into a uranium mine, saying it could not do so without the approval of the Mirarr traditional owners.
It has said its priority would be to rehabilitate the Ranger mine, which comes at an estimated cost of $2.2 billion.
A final four-day hearing regarding the Jabiluka lease will be held from October 28.
