UPDATE 7-RUSAL chairman quits in Russian oligarch fight
* Chairman says RUSAL faces crisis
* RUSAL says Vekselberg failed in his role
* Deripaska says could buy Vekselberg's stake if for sale
* No discussions over selling Norilsk stake since autumn
By Megan Davies and Polina Devitt
MOSCOW, March 13 (Reuters) - Russian billionaire Viktor Vekselberg quit on Tuesday as chairman of UC RUSAL , the world's largest aluminium producer, saying the heavily indebted company was in deep crisis after a long battle with rival oligarch Oleg Deripaska.
Vekselberg's exit widens a rift with controlling shareholder Deripaska, who had sought to build a Russian metals and mining business on a global scale by merging RUSAL with Norilsk Nickel , the world's top nickel and palladium miner.
Energy and metals magnate Vekselberg could now mount a legal challenge to Deripaska's determination to keep a stake in Norilsk, which, if sold, would almost wipe out the company's $11 billion debt burden and enable it to look at other merger opportunities.
"I regret to say at this time that Rusal is in a deep crisis caused by the actions of the management," said Vekselberg, listed by Forbes magazine as Russia's eighth-richest man with a fortune of $12.4 billion.
Deripaska said Vekselberg had failed to fulfill his chairman's role by not attending meetings for a year and was jumping before he was pushed.
"The decision of Mr. Vekselberg to resign as chairman of the board pre-empted the anticipated consideration of this matter by the board," a statement from RUSAL said.
RUSAL's board will pick a new chairman from its slate of independent directors at a board meeting on Friday, Deripaska later told reporters.
RUSAL's shares were suspended after falling 1.3 percent in Hong Kong on Tuesday. The company said it expected trading in Hong Kong and Paris to resume on March 14.
Deripaska, a theoretical physicist who emerged triumphant from Russia's aluminium wars of the 1990s, bought a one-quarter stake in Norilsk through RUSAL four years ago, but the debt that financed the deal became a major headache when the global crisis hit.
RUSAL was forced into a debt restructuring, killing Deripaska's dream of a mega-merger, but he blocked calls by partners Vekselberg and billionaire politician Mikhail Prokhorov to sell the stake back to Norilsk.
"RUSAL is a good company, but the (economic) cycle is not that simple," Deripaska told reporters on a conference call late on Tuesday.
"The events that will influence the price of aluminium lie ahead. I would hardly advise anyone to sell. It is necessary to wait until the Asian and European markets rebalance."
"This escalates the conflict," said Robert Mantse, metals and mining analyst at Otkritie, a Moscow-based brokerage.
"Although most of the disagreements ... are well known, the resignation of Vekselberg shows just how far he and Deripaska now stand apart in the running of the company."
The shareholder dispute is complicated by the outsized egos of Russia's resource oligarchs, with the principal players, including Norilsk's main shareholder Vladimir Potanin, having a long history of troubled relations.
Russia's mining sector is highly politicised, with oligarchs effectively owning their assets at the pleasure of the Kremlin. Vekselberg's resignation follows Prime Minister Vladimir Putin's victory in a presidential election. Prokhorov, running in his first election on a liberal ticket, took third place, though some viewed his candidacy as creating a convenient illusion of democracy that worked to benefit Putin.
Prokhorov's investment company, Onexim, declined comment, as did Norilsk Nickel. Vekselberg was not available for further comment.
Deripaska, having failed to secure influence in steering Norilsk, has spurned three offers by Potanin to buy back the stake at a steep premium to its current value.
After paying an estimated $14 billion in cash and stock for the holding in 2008, he turned down a $13 billion buyout offer from Norilsk in December 2010 and rejected two lower offers in spring and autumn of last year.
"If (Deripaska) looked silly for buying it at the top of the market, he could have looked smart now if he'd (sold) Norilsk in the spring of 2011," said Steven Dashevsky, founder and chief investment officer at Dashevsky & Partners.
"But that required a focus on the value creation of the business," he told Reuters.
No discussions about selling that stake have been held at RUSAL since last autumn, Deripaska said.
"I look at Norilsk Nickel optimistically," he said. "We have not discussed this for a long time with anyone."
RUSAL, which floated in Hong Kong in early 2010, has a market capitalisation of about $12 billion. Its 25 percent stake in Norilsk makes up the bulk of its equity market value, priced at about $9.4 billion.
Analysts and insiders said they see no short-term way out of the deadlock and that no plans are afoot to sell the stake.
One source close to Vekselberg's camp said it had "only one way out -- to sue Deripaska".
While Vekselberg's resignation tightens Deripaska's grip as chief executive of RUSAL, the company faces a struggle to pay off its debt.
Aluminium prices fell sharply last year as China's economic growth slowed, though they have recovered this year after global rivals such as Alcoa cut production. RUSAL's stock, at HK$6.12, is now 43 percent below its IPO price.
Vekselberg is widely viewed as a financial investor who wants quick returns on his investments, while Deripaska has a bullish long-term view on world metals demand and has invested heavily to boost RUSAL's output.
RUSAL said the board would meet on Friday to appoint a new chairman. It is expected to elevate one of its five independent directors, who include Anatoly Tikhonov, first deputy chairman at Russian state development bank VEB.
The move raised speculation that Vekselberg might sell his 15.8 percent stake in RUSAL, which he owns with partners, though the sources close to his camp said that was out of the question.
Deripaska said he enjoyed a pre-emptive right to buy the stake under a shareholder agreement.
"If they sell, we will discuss it," Deripaska said, adding that he spoke with Vekselberg on Tuesday, and that the two had "different views and divergent positions".
Prokhorov has also dismissed suggestions that he might sell his 17 percent stake in RUSAL, which he acquired in a cash-and-stock deal when he sold his one-quarter holding in Norilsk.
He told Reuters in a recent interview that RUSAL and Norilsk should either agree to merge or make a clean break.
"As a former chief executive at Norilsk Nickel, I have a personal opinion that it is better to sit at a table and to make an agreement - who is leaving - or to make a merger of Norilsk Nickel and RUSAL," Prokhorov said.
Deripaska, through his investment vehicle EN+, owns 47.4 percent of RUSAL and has overall strategic control. According to Forbes magazine's latest rich list, Deripaska's wealth nearly halved over the past year to $8.8 billion.
DAVOS, Switzerland - Central banks have done their best to rescue the world economy by printing money and politicians must now act fast to enact structural reforms and pro-investment policies to boost growth, central bankers said on Saturday.