Last June SmartCompany ran an opinion piece by veteran Perth mining writer and Gina Rinehart watcher Tim Treadgold, arguing Rinehart was well on her way to becoming the world’s richest person based on the potential value of her underdeveloped mining iron ore and coal deposits.

Tim would be the first to admit that it was a long-range prediction, with a lot of assumptions — including that commodity prices would remain strong and the smooth development of four key projects, including the expansion of the Hope Downs iron ore mine from 30 million tonnes to 55 million tonnes, the development of the Roy Hill iron ore mine and two Queensland coal projects called Kevin’s Corner and Alpha Coal.

But Tim’s prediction is coming true a lot sooner than anyone thought. Yesterday Rinehart’s fortune doubled to $20 billion and there appears to be plenty of room left to grow.

Last year, Rinehart was valued at $10 billion by BRW, a valuation based mainly on the ongoing royalties she receives from Rio Tinto’s Pilbara iron ore operations. Thanks to the iron ore deposits discovered by her late father Lang Hancock, Rinehart gets a 1.25% cut of everything mined by Rio Tinto’s subsidiary Hamersley Iron. On top of this, she gets half of the profits generated by her Hope Downs mine, also operated by Rio Tinto.

Together, these royalties are delivering something in the order of $1 billion in cash a year — the cornerstone of last year’s $10 billion valuation.

But BRW‘s valuation will increase sharply this year, most likely by at least 100%.

Yesterday, South Korean steel giant Posco announced it had paid $1.5 billion for 15% of the mine, valuing the entire project at $10 billion. In other words, Rinehart gets $1.5 billion in cash and keeps an 85% stake in the mine, worth $8.5 billion.

Even if you don’t value her stakes in the Kevin’s Corner and Alpha Coal projects, or account for the expansion of Hope Downs, Rinehart is sitting on a pile worth about $20 billion.

This is simply an amazing story. It is just six years since Rinehart became Australia’s first female billionaire, but the resources boom and the quality of the assets inside Rinehart’s company Hancock Prospecting means she is challenging for the title of the world’s richest woman.

That mantle is currently held by Walmart heir Christy Walton, who is valued at about $24.5 billion according to Forbes, but you have to wonder whether Rinehart could soon take the title.

Of course, incredible wealth invariably means incredible work and Rinehart has plenty of that in front of her. The first task will be to secure funding for these projects, which is no small job in markets where capital is becoming somewhat constrained. On top of this, developing three projects the size of the Roy Hill mine and the two Queensland projects would be a huge job for any big mining company.

But Hancock Prospecting is a relatively small operation, without the huge management infrastructure needed for such projects. Indeed, the board and management section on the company’s website lists just five people, including Rinehart.

The most likely outcome is that she will look to others to operate the mines, as she has done with Hope Downs and Rio Tinto. This would be the smart play — Rinehart will have companies knocking down her door to do the job and you can bet she’ll drive a hard bargain before making her pick.

But that’s in the future. Right now, we should all stop to recognise the fact that Australia has in its midst an entrepreneur who controls an empire bigger than Frank Lowy, Anthony Pratt, James Packer and Harry Triguboff combined.

And she’s just getting started.

*This article was originally published at SmartCompany