Worth an estimated A$38bn (£20bn; $27bn), Rinehart inherited the iron ore ventures of her father in 1992, before going on to develop mines in the mineral-rich Pilbara region of Western Australia (WA).

Two of her children and the heirs of her late father’s business partners argued they were entitled to a significant share of royalties and mining rights.

On Wednesday, more than 13 years after the legal battle began, a Supreme Court judge ruled that Rinehart must pay past and future royalties to her rival heirs but that the mining rights remain hers.

The legal battle centres around Hope Downs, one of Australia’s largest and most lucrative iron ore projects.

The court heard Rinehart’s father, Lang Hancock, and his business partner, Peter Wright, who were considered iron ore pioneers in WA, drew up an agreement to manage their joint interests under a business called Hanwright.

During the 51-day trial in 2023, Wright’s children argued that Rinehart had breached that agreement and owed them mining rights and royalties stemming from Hope Downs.

The site is jointly operated by global mining giant Rio Tinto and Hancock Prospecting, and last year tipped A$832m into Rinehart’s company’s coffers.

Rio Tinto pays 2.5% in royalties to Hancock Prospecting, with Justice Jennifer Smith ruling half belongs to the Wright family.

“Wright Prospecting won half of its case, lost half of its case, and Hancock Prospecting… has won and lost half of its case,” Smith said.

The legal case also involved two of Rinehart’s children, Bianca Rinehart and John Hancock, who claimed that their mother had moved lucrative mining rights out of a family trust into a part of the business they couldn’t touch.

The pair said their grandfather had intended to share the wealth from the mines at Hope Downs with them, but Rinehart had deliberately denied them access to the fortune.

Rinehart’s lawyers argued that she had moved the mining rights out of the family trust after growing suspicious of her father’s business dealings, but her children argued that she did so to keep money from his second wife, former housekeeper Rose Porteous.

Though Rinehart’s children’s claims over the rights was denied, another bid for royalties from Hope Downs by the family of late engineer Don Rhodes was partially granted.

Hancock Prospecting executive director Jay Newby welcomed the court’s decision, saying it confirmed the company’s ownership of Hope Downs and “firmly rejecting” the claims by Wright’s family and two of Rinehart’s children.

A spokesman for Wright Prospecting also welcomed the decision, saying it was “pleased to finally receive a result in our favour”.

Rinehart is one of Australia’s biggest private donors to sports, charities and conservative political parties.