LONDON (Reuters) - After years of on-off discussions, months of talks and, finally, a deal with his erstwhile adversary in February, Glencore's (>> Glencore International Plc) Ivan Glasenberg is just weeks away from votes that should seal his dream - a tie-up with miner Xstrata (>> Xstrata PLC).

For the highly competitive one-time champion race walker, it has been a long-distance trek he was desperate to win.

"Ivan will see the closing of the deal as a personal victory," said one industry banker. "It is something he has wanted for a long time."

Xstrata floated in 2002 after buying up key coal assets from Glencore, leaving the latter - founded almost four decades ago by commodities trader Marc Rich - with what is now an almost 34 percent stake.

But Glasenberg, chief executive of Glencore since 2002, has long dreamt of reuniting the two in a move that would turn the world's largest diversified commodities trader into a mining and trading powerhouse with over 100 mines and an oil division with more ships than Britain's Royal Navy.

"We've always had the belief these two companies should be together," he said in February, after the advanced talks were first confirmed.

Such was the belief that the South African-born Glasenberg, an intensely discreet man who prided himself that schoolfriends had little idea of his wealth, agreed to relinquish his privacy to give Glencore one element that held back a tie-up over years of talks - a stock market listing.

That, both sides hoped, would put a market price on Glencore and help assuage concerns any merger would be a "sweetheart" deal that might hurt minority shareholders' interests.

Glencore listed last May, giving it the scope for ambitious deals globally - its stated aim - but also the paper needed to facilitate the long-awaited marriage with Xstrata.

Glasenberg's stake in the company - over 18 percent before the IPO, now just under 16 percent - became public, along with his wealth and that of his equally publicity-shy management team. It was a step he compared at the time to "crossing the Rubicon".

The change has not been easy for Glasenberg, an often charming but sometimes gruff, fiery-tempered 55-year-old, or for his team. But he has kept focused on his target, and over a low-key dinner in London in December, he and counterpart Mick Davis agreed the time was right to turn the dream into reality.

LIFE AFTER THE DEAL?

Yet with Glasenberg set to become deputy chief executive of the enlarged group under Davis - the man he picked to run Xstrata more than a decade ago - some shareholders are fretting that determination could lead to tension.

"If a deal gets inked it will be Ivan and Mick's triumph, but Ivan has been the most forceful of the two throughout the proceedings," said a banker familiar with both companies.

Both Glasenberg and Davis are keen sportsmen who cut their teeth in the South Africa coal industry and grew up in Jewish families in apartheid South Africa. They have had a close, but sometimes tense, relationship for over a decade.

But it is unclear how they will work as a team running the same company - Davis as chief executive, and Glasenberg, a major shareholder, as president and deputy chief executive - or how long Davis will stay, after a three-year retention deal expires.

Their supporters say the two, deal-driven men will play to their respective strengths - the compact, wiry Glasenberg as trader and dealmaker and the burly Davis as the miner and public face of the company.

But both are known to drive a hard bargain and not to give in without a fight.

The relationship became fraught during the 2009 downturn, when a debt-heavy Xstrata launched a rights issue, finding Glencore lacking the cash to take up its portion. Instead it agreed to contribute its prized Columbian coal operations.

Negotiations were tough and Davis ended up forcing Glasenberg to sharply lower his valuation for the Prodeco coal assets he contributed.

Both men, known for 70-hour work weeks and heavy travel schedules, showed ambition in their early professional lives after training as accountants in their homeland.

Glasenberg joined Glencore as a coal marketer in South Africa in 1983 and climbed via jobs in Australia, Hong Kong and Beijing before becoming chief executive a decade ago.

Davis became finance director of South African utility Eskom at 29 but quit when he was overlooked for the CEO post. He was an executive for Billiton before it merged with BHP (>> BHP Billiton plc).

(Additional reporting by Victoria Howley; Editing by David Holmes)

By Clara Ferreira-Marques

Stocks treated in this article : BHP Billiton plc, Glencore International Plc, Xstrata PLC