During 2001, Marius Kloppers spent more than 100 nights sleeping on aircraft, a gruelling ordeal made necessary by his role in the integration of BHP and Billiton that created the world's largest mining company. It was the kind of once-in-a-lifetime marathon that would, you might think, be enough for anybody. Apparently not. The chief executive of BHP Billiton is at it again.

Last November, Mr Kloppers launched a £70billion takeover bid for Rio Tinto, the mining industry's No2 - and he has been travelling almost constantly since, as he tries to woo shareholders and placate customers. If the BHP Billiton experience is any guide, then a successful bid for Rio will need Mr Kloppers to clock up even more flight time in 2008.

If he was the kind of single-minded workaholic for whom the rest of life fell a distant second, then such a prospect would, perhaps, be understandable. But Mr Kloppers is far from that.

He is, however, a man of contradictions, an ambitious businessman, a brilliant PhD and a proven corporate predator, yet also a devoted family man (with three children, one adopted) and a vegetarian whose most expensive asset until recently was a simple family Nissan.

When Chip Goodyear, the former head of BHP, announced his retirement last year, Mr Kloppers's name was mentioned as a possible replacement, but there were other, apparently stronger, candidates and the South African was considered an outsider. The BHP board is understood to have been wowed by the 44-year-old's energy and ambition and he got the job.

That ambition manifested itself within months of Mr Kloppers taking the helm as he launched the audacious bid for Rio Tinto. If the deal is successful, it will be one of the largest takeovers in corporate history and will create the biggest company in the UK, bigger, even, than BP.

The Takeover Panel has given BHP until February 6 to decide whether to make its approach formal or to abandon its bid. Given Mr Kloppers's contradictory nature, it is difficult to predict whether BHP will dig in and go hostile or walk away. Most sources close to BHP believe that he will not risk humiliation by walking away, but neither will he throw everything into a knockout bid for Rio. The battle could, therefore, be a long one and there are likely to be many more sleepless nights on planes.

Mr Kloppers entered the mining industry in the same year that Tom Albanese, his rival, joined Rio Tinto. He is a chemical engineer by training, but entered management after gaining a PhD from the highly respected Massachusetts Institute of Technology and an MBA from Insead, the graduate business school. He worked for a short period with McKinsey in the Netherlands before returning to his native South Africa to run an aluminium smelter.

He became part of the circle of brash young executives working for Brian Gilbertson at South Africa's Billiton and was instrumental in merging the company with BHP after the 2001 deal.

“I grew up working for a live-by-the-sword company,” Mr Kloppers said of his time with Billiton. The boldness that he inherited has impressed City bankers, who have rushed to provide funding for BHP's bid.

However, there are risks to living by the sword, as the old saying points out. For example, BHP's bid for Rio has angered the Chinese, BHP's largest customer. The authorities in Beijing are worried that a joint BHP-Rio would control 36 per cent of the world's iron ore reserves. Vale, the Brazilian miner formerly known as CVRD, controls another 38 per cent and China's steel producers, who are helping to create the infrastructure to support the country's extraordinarily rapid growth, fear that they will be hurt by a duopoly capable of dictating prices.

Mr Kloppers's move for Rio could backfire, therefore, if it forces the Chinese to take a blocking stake in Rio. Alternatively, the Chinese may demand lower prices for iron ore, potentially robbing shareholders of a huge windfall from rising prices.

Then there is the opportunity cost of a bid for Rio. BHP's oil division is, at last, beginning to deliver and there are voices within the BHP hierarchy arguing that the company should invest its money in the petroleum sector, instead.

As the BHP-Rio takeover saga progresses, the difference between the two companies and their chief executives may grow more pronounced as the arguments become more forceful. Mr Albanese mirrors Rio in his understated thoughtfulness, Mr Kloppers embodies BHP's bolder, brasher culture - but battles usually demand a readiness to fight on both sides. As Mr Kloppers keeps up his campaign, it seems unlikely that his opposite number will give up without a genuine struggle first.

Curriculum vitae

Born August 26, 1962, Cape Town, South Africa

Education Bachelors degree in chemical engineering, University of Pretoria; PhD from the Massachusets Institute of Technology; MBA from Insead, France

Career 1992-93, management consultant, McKinsey in the Netherlands; 1993, general manager Hillside Aluminium and then group executive of Billiton; 2001, takes on a series of roles at the new BHP Billiton, including chief marketing officer, chief commercial officer and group president for nonferrous materials; 2006, executive director of BHP

Family Married to Carin, three children