The study comes as Rio
Rio, already the world's number two-ranked iron ore miner by volume behind Brazil's Vale
Rio immediately rebuffed the overture, although BHP has persisted in promoting what it calls "compelling synergies" in a tie up, underscored by the two companies neighbouring iron ore operations in Australia.
Britain's Takeover Panel on Friday ordered BHP to decide by Feb. 6 whether to make a bid for Rio or walk away under a 'put up or shut up' clause. [ID:nL21473594]
BHP said it had yet to decide on its its next move.
A tie-up would assemble a massive controlling force across a range of industrial-use commodities beyond iron ore, such as copper, aluminium and coal -- raw materials driving growth in emerging nations such as China and India.
Rio this year became a titan in world aluminium making after acquiring Canada's Alcan for $38 billion.
BHP has said a marriage would create value for shareholders in both companies, generating $3.7 billion in synergy benefits after seven years, and has pledged to buy back $30 billion in shares if the deal goes through.
The $71 million study in the Pilbara follows a commitment by Rio to spend a further $350 million to rapidly boost projected output at the Hope Downs mine, pre-dating BHP's proposal.
Work on the 22 million tonnes a year Hope Downs project started last year at a cost of $1 billion, with the first production runs expected by early 2008.
The expansion work, with 50-50 joint venture partner Hancock Prospecting Pty. Ltd., will take annual output from Hope Downs to 30 million tonnes a year by early 2009
Analysts predict that prices mining companies charge steel mills for iron ore will rise by 50 percent or more in the next shipping year starting April 1, 2008, which would mark the sixth straight year of price hikes.
Rio's profits from its iron ore division could top $3 billion in 2007, maintaining its ranking as the company's second-largest income getter after copper, according to analysts' forecasts.
Rio was 1.9 percent higher at A$131.00, while BHP was trading 2.3 percent up at A$40.58, slightly outpacing a 1.5 percent rise in the S&P/ASX200 <.AXJO> index. ($1=A$1.15)
本文转自：China Industry News