* Rinehart reveals details of privately held Hancock Prospecting
* Hancock Prospecting made A$1.9 bln in two years to June 2011
* Hancock Prospecting borrowed money from Rio Tinto
By Jane Wardell
SYDNEY, Jan 4 (Reuters) - Australian mining mogul Gina Rinehart gave in to pressure from the corporate watchdog to disclose details of her fortune, filing reports that show her privately held firm raked in profits of nearly A$1.9 billion ($2 billion) over two years.
The documents, filed on Christmas Eve, showed that after-tax profits at Hancock Prospecting Pty Ltd, named after the heiress' father Lang Hancock, almost doubled to A$1.2 billion as of June 30, 2011, compared with A$688 million a year earlier.
The publicity-shy Rinehart, Asia's richest woman, had long fought demands from ASIC for the financial reports on the grounds that they would divulge commercially sensitive details about her Hope Downs iron ore joint venture with Rio Tinto PLC and her plans to build the $10 billion Roy Hill mine.
The reports released by the Australian Securities and Investments Commission on Friday also revealed that Hancock Prospecting borrowed money from Rio Tinto.
The development of Hope Downs, a major source of Hancock Prospecting's revenues, in Western Australia benefited from the demise of the decades-old annual price fixing of iron ore in 2009, which enabled prices to ebb and flow with demand.
Over the two financial years covered in the reports, prices of iron ore for immediate delivery went from a low of $77 a tonne to a peak of $191.80 - a more than twofold jump.
Since then, prices have dipped as low as $80, but have recovered to around $150.
Hancock Prospecting sat on a cash pile of A$1.68 billion as of June 30, 2011, and more than doubled its dividend to A$12.5 million from A$6.1 million in 2010, according to the reports.
Gina Rinehart's father and Peter Wright discovered vast tracts of iron ore in the Pilbara in the 1950s and owned tenements jointly through a partnership known as Hanwright. With both men no longer alive, ownership fights have raged between the prospectors' descendants for years.
Rinehart, whose fortune was estimated by Forbes at around $18 billion last year, is also fighting three of her four adult children over control of a $4 billion family trust that is funded by the profits from Hope Downs.
The documents filed with ASIC refer to unspecified legal actions that seek royalties from the Hope Downs mine.
"At this time it is not possible to quantify what, if any, damages could be awarded if the claim were to be successful," the company said in the 2011 report, which was first demanded by ASIC in September 2011.
The documents also show that Rio Tinto loaned money to Hancock Prospecting to allow the company to contribute its share of funds to the latest mine, and as of June 30, 2011, Hancock still owed more than $83 million to Rio Tinto.
But the company also reaped $1.26 billion by selling undeveloped coal deposits in Australia's land-locked Galilee Basin to India's GVK Power & Infrastructure Ltd, controlled by Indian billionaire G.V. Krishna Reddy. Hancock retains a minority stake.
The 58-year-old Australian billionaire is currently seeking to secure funding for her flagship Roy Hill mine, rail and port project.
Hancock Prospecting owns about 70 per cent of Roy Hill Holdings, with South Korean steel giant POSCO, Japanese trading company Marubeni Corp, South Korea's STX Corp, and Taiwan's China Steel Corp jointly holding the remaining 30 percent.