If the merger of Glencore and Xstrata goes ahead, the new company, GXI, will be the fourth-biggest mining group by market capitalisation, behind BHP Billiton, Vale of Brazil and Rio Tinto.

Two of the "big four" will be run by South Africans. Marius Kloppers is CEO of BHP Billiton, and Ivan Glasenberg and Mick Davis will together be skippering the new powerhouse.

The proposed organogram for GXI has Davis as CEO and Glasenberg as his deputy and president of the company.

Davis and Glasenberg know each other well and have a lot in common. Described as "frenemies" by the Wall Street Journal, both are South African, both are Jewish and both have made vast amounts of money leading global corporations into extraordinary positions of power.

Glasenberg, who went to Hyde Park High School and the University of the Witwatersrand, is known for both his fiery temper and his charm. After an MBA in the US, he landed a job in 1983 at Marc Rich & Co, the trading house that became Glencore.

In 1990 he became head of the coal department at the company's headquarters in the small Swiss town of Baar. By 2002 he was CEO.

He is said to have hand-picked Davis to skipper Xstrata in October 2001. The following year, Xstrata bought up Glencore's key coal assets, leaving the trader with a 34% stake, and listed on the London Stock Exchange.

Glasenberg, whose personal wealth is estimated to be about $8-billion, made a cool $5-billion from Glencore's pre-listing initial public offering last year.

Davis went to Theodor Herzl High School in Port Elizabeth and then Rhodes University in Grahamstown. He started working as an accountant at Peat Marwick Mitchell & Co and then joined Eskom, where he was finance director at the age of 29. He left the position when he was overlooked for the CEO post. Davis then went to work at the industrials conglomerate Gencor and, with the help of Brian Gilbertson, got the company listed in London and renamed it Billiton.

He was instrumental in brokering the merger between Billiton and Australia's BHP in 2001, but turned down a senior post in the new conglomerate and moved over to Xstrata.

As well as being chairman of the United Jewish Israel Appeal, a registered charity in England and Wales, Davis is a member of the Jewish Leadership Council and is active in the South African Jewish community.

Before he moved to England, Davis served on the executive of the Union of Orthodox Synagogues and chaired the Euro Chai South Africa Charity Trust, which supports old age homes, orphanages and special needs facilities.

As well as pulling off some extraordinary deals, the Glasenberg-Davis relationship has had its difficult patches.

In late 2008, early 2009, Davis wanted to launch a rights issue to cover some of Xstrata's growing debt burden, but Glasenberg's Glencore - which owns 34.5% of Xstrata - could not or would not lay out the cash needed to stop its stake from becoming diluted. According to sources in the Wall Street Journal, several heated discussions ensued, until the two eventually worked out a deal in which Glencore would sell a Colombian coal mine for $2-billion to Xstrata to raise the cash it needed to prevent a share dilution, retaining the right to repurchase it for $2.25-billion.