The battle over the Rinehart family's multibillion-dollar trust will continue to be played out in public after the mining magnate failed to force her children into confidential arbitration.
Gina Rinehart, who is Australia's richest woman with an estimated worth of $17 billion, is fighting three of her four children for control of the trust, which contains 23.45 per cent of shares in the family's flagship company, Hancock Prospecting.
On Friday the NSW Court of Appeal found in favour of John Langley Hancock, Bianca Hope Rinehart and Hope Rinehart Welker, who had fought to ensure the dispute was held in open court.
But Mr Hancock said he expected his mother to seek special leave to appeal to the High Court.
Mrs Rinehart sought - unsuccessfully - to overturn the Court of Appeal's decision to lift the suppression orders covering the case.
''One side in this has the money to appeal each of their failures to the High Court - the other side wins but does not receive costs for many months,'' Mr Hancock said.
In a unanimous judgment, the three judges dismissed Mrs Rinehart's argument that all members of the family signed an agreement in 2006 to keep their feuding out of the courts.
Under the Hope Downs Deed, all conflicts would be referred to confidential mediation or arbitration in Western Australia.
But in September 2011, the three eldest children took urgent action in the NSW Supreme Court after their mother wrote to them days before the trust was to vest, telling them to let her retain control of it.
Mrs Rinehart said she had received advice that if they were to receive their share of the trust, they could each be liable for a $142 million capital gains tax bill.
The three claimed this behaviour amounted to serious misconduct and sought to have her removed as trustee.
They also say she has refused to handover accounts for the trust dating back to 1992.
Chief Justice Bathurst said: ''None of these matters … involve invoking or enforcing any rights created by the settlement deed nor is their outcome generated or controlled by the settlement deed.''