Gloucester’s largest shareholder Noble last week upped its bid for Gloucester by 24% to $A6 a share, or $490 million, in an attempt to prevent the producer merging with fellow Australian coal producer Whitehaven.

Under the Whitehaven-Gloucester merger, Whitehaven shareholders would be offered one Gloucester share for every 2.45 Whitehaven shares.

Noble has labelled the merger a reverse takeover of Gloucester and said its bid was at a 91% premium to the closing price of Gloucester on February 19 – the day before the initial merger announcement.

In a letter to shareholders yesterday Gloucester said it would consider the offer, but advised shareholders not to take action.

“Noble has demanded that the Gloucester board immediately announce its view on Noble’s bid. We think the interests of Gloucester Coal’s shareholders are best served by a careful consideration of all matters,” Gloucester managing director Rob Lord said.

Noble will send a bidders statement to Gloucester shareholders this Friday, which must remain open for at least one month.

Gloucester said it would release its response to both bids by May 21.

A merger between Gloucester and Whitehaven would create a $1.2 billion company that holds combined reserves of 190 million tonnes and resources of 922Mt with saleable production of 4.5Mt, as of calendar year 2008.

Hong Kong-based commodities trader Noble currently holds 21.7% of Gloucester.

Mid-morning today Gloucester was trading at $5.92 while Whitehaven shares were unchanged at $2.12.