* Rio a potential suitor due to Namibian mine proximity
* Analayst warns Rio may be put off by China's buying power
* Break clause means any counter offer needs 5 percent premium
* Rio owns 14 percent stake in Extract and its parent Kalahari
* Extract shares up, Kalahari 4.5 percent above offer price
(Adds analyst comment, shares, background)
By Lorraine Turner and Sonali Paul
LONDON/MELBOURNE, March 8 (Reuters) - China's move on Kalahari Minerals could flush out other bidders for the uranium miner but even long-term suitor Rio Tinto may baulk at getting into a bidding war with such a formidable foe.
Any buyer would secure access to one of the world's biggest uranium deposits at a time when major powers, led by China, are scrambling to secure alternative, and increasingly scarce, sources of energy as oil prices surge.
Uranium is in particularly short supply with governments having to rely on material from decommissioned nuclear warheads to meet demand.
Kalahari said on Monday that China Guangdong Nuclear Power Holding Corporation (CGNPC) had proposed a 756 million pound ($1.2 billion) offer, lured by London-listed Kalahari's 43 percent stake in Extract Resources.
Australia-based Extract owns the Husab uranium project in Namibia. Kalahari said the Chinese would be an "excellent partner" in developing the site and that it was ready to recommend any formal offer.
China has invested heavily in securing global commodities to fuel an economy that grew more than 10 percent in 2010.
Companies have made $15.2 billion worth of overseas acquisitions of uranium companies alone since 2003, Thomson Reuters data shows.
London-listed Kalahari was trading 4.5 percent above the 290 pence per share offer price on Tuesday, suggesting that the market is expecting a higher bid.
"Rio has flagged a willingness to undertake those sort of small-to mid-tier transactions," said Ben Lyons, an analyst at ATI Asset Management, which owns Rio Tinto shares.
Rio Tinto, on the lookout for acquisitions worth $5 billion or less, owns 14 percent of Kalahari. The mining giant declined to comment on whether it would mount a bid. Japan's Itochu Corp also owns 14 percent of Kalahari.
MONEY TO BURN
London-based mining analyst Charlie Long at Singer Capital Markets, also noted that the share price indicated a counterbid was likely although he said it would be surprising if China had not already held talks with top shareholders such as Rio. "If you're the Chinese, they have got so much money, they need supplies of uranium, is it really worth having a bidding war with the Chinese government? Where would that end up? And the Chinese probably don't care how much they spend," said Long. Long also noted that under the terms of agreements already reached between CGNPC and Kalahari, any Rio offer would have to be at least 5 percent higher than that already on the table.
Shares in Kalahari were up 6.4 percent at 303.25 pence in London by 1405 GMT while Extract Resources jumped 7.3 percent in Sydney on expectations that Rio may also make an offer for the Namibia-focused miner in which it also owns 14.2 percent. "We have felt that Rio Tinto, which operates the neighbouring Rossing mine in Namibia, was the most likely consolidator in the region and are therefore inclined to hold Kalahari to see if a bidding war develops," analysts at Killik & Co wrote in a note to clients.
Reuters reported in September 2009 that Extract and Kalahari were likely to prove tempting targets for both Rio Tinto and the Chinese government.
Killik analysts noted that uranium prices are likely to rise as demand for electricity from power stations rises, particularly if people switch to electric cars.
"According to industry figures, there are currently about 435 nuclear reactors worldwide, with a further 430-plus either under construction, planned or proposed," they wrote. "Current levels of uranium mining only satisfy around 65 percent of the annual demand for uranium in the reactors." ($1=.6184 Pound)
(Additional reporting by Taiga Uranaka and Terril Jones; writing by Paul Hoskins; Editing by Michael Flaherty, Neil Fullick and Hans Peters)