The prolonged legal battle among the Rineharts, Australia's richest family, took an uglier turn as Ginia, the youngest daughter who is the only child of billionaire and mining magnate Gina Rinehart, dug up and exposed her older sister's previous eating disorder.

The reason behind such a revelation, which their mum desperately tried to stop by legal means, was to stop sister Bianca from replacing their mother as trustee of a family trust the patriarch, Lang Hancock.

Bianca's eating disorder was during her late teen years and she has recovered from the ailment, thanks to expensive treatments paid by her mum when the two were still in good terms.

In another twist to the family feud, Bianca chose not to fight back Ginia and instead withdrew her bid to become the foundation's trustee.

Bianca explained, quoted by The Sydney Morning Herald, "Ginia's lawyers want to investigate my medical history ... My whole family know I had an eating disorder in my late teens. I love my sister and bear no animus towards her for this approach and I'm addressing it as I strongly feel that nobody should be ashamed to seek help for any mental illness and have the support of their loves ones in so doing."

Bianca, now 37, and married with a son, actually worked as director for the Rinehart company, Hancock Prospecting, for 13 years until the falling out with her mum. Since the ailment was never an issue when she was director, Bianca believes it would not be an issue if she would be appointed as trustee of the Hope Margaret Hancock Trust.

YouTube/bruno ws

However, to avoid further worsening the broken family ties, Bianca - who was also treated for depression in 2000 and 2003, although it is not related to her previous eating disorder - nominated her husband, Alexander Vladimir Serebryakov, to be her replacement as trustee nominee.

"My husband's motivation in agreeing to be put forward as a trustee replacement was to shield me for further such personal attacks by Ginia's lawyers," Bianca added.

Mr Serebryakov is no stranger to the mining industry since he is currently the general manager for business development at Rio Tinto.

Bianca added she is not ashamed of admitting her past struggles with mental illness, pointing out, "My experience and overcoming the illness has enabled me to positively support others struggling with the disorder."

Because of how the legal battle has further exposed the family secrets, Ms Rinehart, named over the weekend as chairperson of the year by CEO Magazine, agreed to give up being trustee of the foundation.

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