Anglo-Australian mining giant Rio Tinto (NYSE:RTP) suddenly has a new chairman -- Jan du Plessis, currently the chairman of British American Tobacco. And I'd wager that the company has also found a means to begin extricating itself from the mountain of debt it's become buried in.

Du Plessis becomes Rio Tinto's second chairman-designate in as many months. Its first choice, Jim Leng, chairman of European steelmaker Corus, handed in his keys in February as a successor to Paul Skinner, over a rift involving a proposed $19.5 billion stake sale to Aluminum Corp. of China (NYSE:ACH) -- or Chinalco to its friends.

What a set of circumstances for a company that not long ago was riding high, having easily borrowed the $38 billion necessary to pay cash for Canada's aluminum manufacturer Alcan. In the process, it outbid Pittsburgh-based Alcoa (NYSE:AA) -- as it watched its commodities, which run from aluminum to zinc, advance to ever higher prices.

But now Rio Tinto's prices have plummeted, it's cutting production, and it's laying off workers. The Chinalco deal would involve devoting $12.3 billion to take significant positions in several of Rio Tinto's major assets and would double the Chinese company's current stake in Rio Tinto to as much as 18%, if the $7.2 billion in convertible bonds are exercised. It also would provide Rio Tinto -- the third-largest mining company behind BHP Billiton (NYSE:BHP) and Vale (NYSE:RIO) -- with the wherewithal for a $10 billion debt payment in October.

But while du Plessis clearly is in favor of the Chinalco deal, his position does not enjoy unanimous support. At least one major shareholder and several Australian lawmakers have expressed concerns about dilution from the deal, as well as about having Rio Tinto's assets becoming controlled by Chinese interests. As a result, Australia's Foreign Investment Review Board has tacked on an additional 90 days to the review proposal. That new twist pushes a shareholder vote out until July.

The mining and metals sector has experienced an unbelievably topsy-turvy period of late. Nevertheless, while some commodities remain in the doldrums, others have begun to experience higher prices. My advice to my Foolish friends is to watch the sector -- and especially events in Australia -- very closely. It seems highly unlikely that, given a reasonable period of time, most of the world's major metals and minerals won't resume an upward trek.

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