Less than two years ago, London-based mining and minerals giant Rio Tinto (NYSE:RTP) seemed firmly perched at the top of its sector. It had just bested Pittsburgh-based Alcoa (NYSE:AA) to purchase Canada's Alcan -- easily borrowing $39 billion to get the deal done -- its commodity prices were soaring, and it was in the early stages of fending off a rich buyout offer from Australia's giant BHP Billiton (NYSE:BHP).

At least for now, Rio Tinto's fortunes have reversed themselves. The company needs to raise funds to repay the first installment -- nearly $9 billion -- of its Alcan bank debt, and its board is squabbling over the best way to round up the needed cash. More than a few shareholders are also disconsolate over the spurning of what ultimately could have been a lucrative offer from BHP. And today, depressed commodity prices have dragged Rio's share price down 80% from its 52-week high.

Beyond that, Rio's chairman-designate, Jim Leng, kicked off this week by tendering his resignation after just a month in his position. It seems that much of the board -- including CEO Tom Albanese -- favors raising funds through a sale of convertible debt (and minority interests in some properties) to Aluminum Corp. of China (NYSE:ACH) -- Chinalco to its friends. Chinalco, together with Alcoa, already owns a 9% stake in Rio Tinto. This so-called "Chinese Solution" could raise as much as $20 billion for Rio.

Leng strongly preferred to opt for a rights offering. Issuing new shares, he argued, was less risky than selling assets, given the current economic climate. Rio may struggle to fetch realistic values for the properties.

However, there may be other money-raising options for Rio Tinto. The company appears to be discussing the sale of as-yet undisclosed assets to Japan's commodity trading house Mitsui, which also happens to be a part-owner of a Rio Tinto iron ore mine in Australia. Beyond that, Rio is also reportedly in talks with Australian packing company Amcor (OTC BB: AMCRY) regarding the sale of a Rio Tinto packaging unit.

Should investors view Rio Tinto as a long-term opportunity? Despite shares' year-over-year tumble, I wouldn't invest heavily in them at this point. But once the global economy improves, the world's largest mining companies, including BHP Billiton, Brazil's Vale (NYSE:RIO), and Rio Tinto, will almost certainly deserve your careful scrutiny.  

Rio Tinto is currently decked out in four stars, as decided by the Motley Fool CAPS community. Have you weighed in with a thumbs-up or thumbs-down on the company?

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Fool contributor David Lee Smith doesn't own shares in any of the companies mentioned. He does, however, welcome your questions or comments. The Fool has a disclosure policy.