Gina Rinehart, richest woman of Australia and of the world, has lost an 11-year old court battle to repossess from rival miner Wright Prospecting Pty Ltd. a 25 per cent stake in the Rhodes Ridge three billion tonne iron ore deposit in Western Australia.

In March 2010, Ms Rinehart's Hancock Prospecting was ordered by the court to surrender to Wright Prospecting its 25 per cent per cent stake in the project, effectively boosting the latter's hold on the project to 50 per cent. As expected, Ms Rinehart and her camp immediately lodged an appeal to nullify this order.

But the Western Australia Court of Appeal on Tuesday with finality quashed Ms Rinehart appeal, backing the 2010 order which leaves Wright Prospecting with 50 per cent of the Rhodes iron ore asset, which is expected to be worth billions of dollars once developed. The remaining 50 per cent is controlled by joint venture partner Rio Tinto, which entered into the JV way back the time of the Wright-Hancock prospecting partnership.

"The company is pleased that today's ruling upholds those rights and the original judgment," a spokesman for Wright Prospecting said in an emailed statement.

Lang Hancock, Ms Rinehart's father, and Peter Wright, were not only business partners but also close friends. The two gentlemen in 1984 entered into an agreement carving and detailing up their assets to avoid potential future squabbles between their descendants. Mr Wright died in 1985, Mr Hancock in 1992.

The battle for the Rhodes Ridge three billion tonne iron ore deposit ensued when Ms Rinehart's Hancock Prospecting claimed the 1984 agreement was superseded by a 1989 management deal, which meant that Ms Rinehart gets to maintain the 25 per cent stake supposedly for Wright Prospecting.

Three Supreme Court judges in Perth handed down Tuesday's unanimous verdict.

"Throughout this matter and the previous matter in the Supreme Court, Wright Prospecting's focus has been to enforce and protect its rights to 50 per cent of the Rhodes Ridge joint venture," the Wright Prospecting spokesman said.

As expected, Hancock Prospecting would oppose the orders and refile for an appeal. They are given until Nov 13 to lodge the submissions while Wright Prospecting had until Nov 20 to respond.