Fresh from being crowned Australia's richest person, the accounts of Gina Rinehart's private company Hancock Prospecting, reveal the stratospheric rise in her fortunes last year as the family's Roy Hill mine kicked into high gear.

The company doubled its net profit to more than $1.07 billion and unleashed a cash bonanza for its owners with a $767 million dividend.

The vast majority of this dividend, $587 million, will be paid to Rinehart who was listed by Forbes this week as Australia's richest person, after a recovery in iron ore prices boosted her estimated fortune to $US16.6 billion ($21.5 billion).

Hope Margaret Hancock Trust, which is now controlled by Rinehart's estranged daughter, Bianca Rinehart on behalf of her siblings, owns 24 per cent of Hancock Prospecting.