Fierce court battle for Hancock mining riches concludes

Justice Jennifer Smith reserved her judgement on Wednesday following a bruising 51-day battle for spoils from the massive Rio Tinto-operated Hope Downs mining complex in Western Australia.

She also warned the warring parties could return to the Supreme Court in Perth to recommence the fight over privileged documents and confidential arbitration involving Mrs Rinehart's eldest children John Hancock and Bianca Rinehart.

The complex battle that started in July pitted Mrs Rinehart's company Hancock Prospecting against the heirs of mining pioneer Peter Wright and engineer Don Rhodes amid allegations of decades-old contract breaches.

Justice Smith closed the court to the public and media for most of the final day of the marathon trial to hear arguments from mining giant Rio Tinto and Hancock Prospecting about who should foot the bill for the royalties if Mrs Rinehart's company loses.

But not before the billionaire's lawyer, Noel Hutley SC, attempted to lay one final blow in response to reply submissions from the Wrights' lawyer, Julie Taylor, amid a weeks-long cycle of closing submissions and replies that led to the parties making even more submissions.

It prompted Justice Smith to jovially quip that "it always seems to be a competition as to who's going to have the last say" when Mr Hutley had concluded.

"I can tell you all it's ultimately going to be me," she said as the courtroom broke into laughter.

About two dozen lawyers costing an estimated $250,000 per day have packed the courtroom for the hearings that have also seen John Hancock and Bianca Rinehart legally represented over a claim their grandfather Lang Hancock left them a hefty share in the Pilbara mining resources he discovered in the 1950s.

Wright Prospecting is demanding a share of unmined and mined Hope Downs tenements and royalties, amid a claim that Hancock Prospecting breached a 1980s partnership agreement.

DFD Rhodes is claiming a 1.25 per cent royalty share of Hope Downs' production, over an alleged deal with Mr Hancock and Mr Wright that handed over tenements in the 1960s.

The trial has also featured sensational claims against Mrs Rinehart - which have been vehemently denied - including that she allegedly devised an unlawful scheme to defraud her children.

Justice Smith said in her closing remarks that the case would "turn upon an assessment of the large volume of historical documents" as she thanked the "smartest legal minds in Australia" for an "enjoyable trial".

She also complimented the parties for "meticulously and carefully" presenting their clients' cases and the high standard of their submissions.

Mrs Rinehart inherited her father's iron ore discovery in WA's Pilbara region and forged a mining empire after he died in 1992.

She developed mines from tenements at Hope Downs, signing a deal in 2005 with Rio Tinto, which has a 50 per cent stake in the project.

The Hope Downs mining complex near Newman is now one of Australia's largest and most successful iron ore projects, comprising four open-pit mines.

Her wealth is estimated to be about $36 billion and she is executive chair of Hancock Prospecting.

Australian Associated Press