A long-running legal battle for a bankrupt US copper company has led Vedanta, the London-listed Indian miner, to enter a Texas courtroom this week with a raised cash offer.

Vedanta, which produces copper and zinc in India, confirmed yesterday that its subsidiary Sterlite Industries had raised the cash portion of its bid for Asarco, the US copper miner, from $1.1bn to $1.59bn in a court-mediated auction.