Gina Rinehart offered to give her daughter Hope Welker $300 million and set her up for life if she agreed to pull out of the bitter court action she launched against the mining magnate.
The offer, which was repeatedly rejected, was made within weeks of Mrs Welker filing paperwork in the NSW Supreme Court accusing her mother of "deceptive, manipulative and disgraceful conduct".
The previously secret settlement bid is referenced in a series of heated emails obtained by The West Australian in which the 26-year-old is urged by her younger sister Ginia to: "Just take the 300 MILLION dollars mum has repeatedly offered you and walk away."
The offer was made in late 2011, shortly after Mrs Welker and two of her siblings John Hancock and Bianca Rinehart launched legal action to have Mrs Rinehart removed as head of the family trust.
Mrs Welker officially withdrew from the case this week after reaching a settlement with the mining magnate.
It is not known if the terms of the settlement relate to the $300 million offer. It is also believed that of Mrs Rinehart's three estranged siblings, only Mrs Welker was offered a deal.
Tensions in the increasingly bitter family feud have escalated in recent weeks, coinciding with Mrs Welker's withdrawal. As revealed in The West Australian two weeks ago, the 26-year-old asked to withdraw from the case because she is broke, separated from her husband and unable to pay her share of the $100,000-a-month legal fees.
At the same time, John Hancock has publicly criticised executives at the family company, Hancock Prospecting, for their role in the feud and questioned the ability of his sister Ginia to take over the reins of the company.
This week, Mrs Rinehart's lawyers released emails which revealed that days before the legal action was launched, Mr Hancock had unsuccessfully attempted to come to a secret arrangement with his mother over her decision to delay the vesting of the family trust.
Emails reveal that within weeks of the legal action being launched, Mrs Rinehart had sought to make a deal with Mrs Welker to drop out.
The messages lay bare the gulf between the two sides of the dispute in the weeks after the action was launched.
On November 2011, Mrs Welker wrote to her sister, Ginia, saying Mrs Rinehart had cut off her trust payments, she was broke and she needed help with her children's school fees.
"I'm in a corner with a gun at my head," she pleaded. "I can't afford rent, I can't afford the kids' education. I don't know who else to ask. Please help."
The next day, an angry Ginia replied, refusing to help her and labelling her sister's plea "disgusting".
"When will you look in the mirror and realise how stupid you are being! How dare you spend your money on this litigation which is ruining my life and then not keep enough to pay your own daughter's school fees! And then ask ME to pay," she wrote.
In an email sent three weeks later, Mrs Welker was again urged to take the $300 million.The case returns to court next month.
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