Federal government claims an Indigenous win over a mining lease would lead to massive native title payouts across the Top End are "speculative", High Court justices have heard.
The High Court sitting in Darwin on Thursday heard a response by the Gumatj Clan to an appeal arguing the Commonwealth will be liable for "vast amounts of compensation" if findings from the group's court win are not overturned.
In May 2023, a decision by the full bench of the Federal Court paved the way for the Gumatj Clan to receive up to $700 million in compensation for bauxite mining at Gove in northeast Arnhem Land.
Gumatj Clan lead barrister Arthur Moses SC told the special sitting of the full High Court bench the claim was based on "speculation" and incomplete historical maps lacking "significant probative value".
"The Commonwealth has prophesied a vast extent of claims across the Northern Territory ... it advances no supposition that a vast amount of areas had native titles as of 1911," Mr Moses said.
Commonwealth solicitor-general Stephen Donaghue KC previously told the full bench of the High Court the case would invalidate a large number of land grants made in the NT after 1911 that did not compensate native title holders.
The late Yunupingu originally brought the case that found the Gumatj Clan's land was not acquired "on just terms" before being leased in 1968 to the Swiss-Australian mining consortium, Nabalco.
Mr Moses told the High Court justices on Thursday the Gumatj Clan's case was simply to "redress past wrongs" after their land was unjustly taken from them by the federal government's 1968 mining lease.
"It impaired the rights of these people and others to their lands. It caused immense upheaval to these people and their way of life that continues to this day (via) high levels of stress and loss of opportunity," he said.
Mr Moses read to the justices from the writings of Yunupingu about seeing his father trying to stop bulldozers from destroying sacred trees on the Gove peninsula.
"I watched him cry when our sacred waterhole was bulldozed," Yunupingu wrote in 2005.
Dr Donaghue previously told the High Court justices the landmark Mabo decision had established native title was susceptible to extinguishment or impairment by exercise of the sovereign power to grant interests in land.
Mr Moses said native title had been created by the traditional laws and customs of Indigenous people thousands of years before the Sovereign Crown arrived in Australia.
"Most of us in this court, except for younger associates, lived in times when terra nullius was orthodoxy, taught in schools and used as a blunt tool to deprive First Nations people of rights," Mr Moses said.
He said the High Court's striking down of terra nullius had established native title as Indigenous people's property rights that should be safeguarded by the constitution in the same way as the rights of all Australians.
"When property is acquired by the Commonwealth it is required to pay compensation on just terms. It applies to any person. It applies to native title," Mr Moses said.
Justice James Edelman asked Mr Moses if native title had been created by Indigenous culture or had been created by common law being adapted to recognise Indigenous culture.
"None of the cases before the court have suggested native title was changed by anything since the arrival of the Sovereign" Mr Moses said.
The High Court's special sitting in Darwin for the Commonwealth's appeal will hold its last scheduled hearing day on Friday.
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