Analysts from Royal Bank of Scotland (RBS) said on Wednesday that giant mining firms BHP Billiton Ltd and Rio Tinto Ltd could soon be eclipsed by the soaring iron ore production of Fortescue Metals Group Ltd.

The unprecedented overtake could very well happen as early as 2017, by which time FMG's output would have reached 355 million tonnes per annum (MTPA) from its present level of 40 MTPA and compared to both BHP's and Rio Tinto's same period projected production of 298 MTPA and 344 MTPA.

Yet before that could happen, RBS analyst Lyndon Fagan said that Fortescue would need to raise some $US18 billion or $A19.3 billion in debt financing that would buttressed its expected ramp up production over the next seven years.

Mr Fagan noted that the 355 MTPA forecasted by RBS was inclusive of the proposed Anketell Point port project as he reminded that from today and up to 2017, the projections could potentially be altered once the planned merger of BHP-Rio Tinto iron ore ventures pushed through but analysts have already discounted its possibility.

The RBS analyst said that the likelihood of FMG climbing all the way to the top and become Australia's number one mining firm is very high considering that the company has shown in the past that it can deliver the goods.

Basing on his iron ore price estimates, Mr Fagan was convinced that FMG could solely finance expansions of up to 155 MTPA by 2014 and the company would only require some $US10 billion of debt financing to take the figures further into 355 MTPA only three years after.

The worst thing that Fortescue could encounter on its way up is to see its target debt facilities ballooning to a high of $US18 billion, that is if iron ore prices retreated to $US60 per tonne in 2012 then further scaled back to $US48 per tonne by 2016.

At any rate, Mr Fagan said that FMG could always rely on additional debt and internal cash flow to ramp up its production given its propensity to shun capital raising that dilutes the company's share base, stressing that Fortescue could definitely count on its bigger size as compared with both BHP and Rio Tinto.