Linklaters has been drafted in on its second major mining deal in a week, advising British mining giant and longstanding client Rio Tinto on its £50bn approach from Australian rival BHP Billiton.

BHP Billiton confirmed that it had approached Rio Tinto but that the offer, which would have created the world’s biggest mining company, had been rejected.

It is understood that BHP Billiton has turned to longstanding UK advisers Slaughter and May, although neither Linklaters or Slaughters would comment on the deal.

Slaughters and Linklaters were opposite each other in 2001 on the £7.2bn merger of legacy companies and respective clients BHP of Australia and Billiton of the UK.

The approach follows Wednesday’s news that Linklaters advised AIM mining client Nikanor on its planned £1.6bn tie-up with Toronto-listed mine and Norton Rose client Katanga (, 7 November).

It was only in July that Linklaters advised Rio Tinto on its £16.75bn bid for Canadian aluminium company Alcan, advised by Freshfields Bruckhaus Deringer. BHP Billiton waited until that deal formally completed yesterday before making its move.

Meanwhile, the approach comes as BHP Billiton is undergoing an overhaul of its legal team, with chief legal counsel John Fast retiring in the new year, to be replaced by Freehills’ managing partner Mike Ferraro (The Lawyer, 10 October).