American companies First Reserve and Alpha Natural Resources (NYSE:ANR) are contemplating a $3 billion takeover of Australia's Whitehaven Coal (ASX:WHC), which has confirmed it has had a data room open to suitors for some time.

Whitehaven shares climbed as much as 5.2 per cent to a record high of $6.45, valuing the coal firm at $3.15 billion.

Targeted for its high-quality thermal and coking coal, Whitehaven said on August 5 it was discussing with third parties potential deals but did not reveal names or details on whether its suitors were in interested in a takeover, buying stakes in the company or stakes in its mines.

"Whitehaven confirmed that the company has had a data room in place for a long period of time for use in relation to various potential transactions," the company said in a statement sent to Reuters.

The Australian newspaper said the two US firms were seeking support from Whitehaven's second-largest shareholder AMCI to acquire the coal company and sell portions of it to Alpha, a coal producer in Wyoming and eastern US.

Private equity company First Reserve already has a 27 per cent stake in Whitehaven, which last week climbed more than 12 per cent on reports that it might be a buyout target.

First Reserve and AMCI share a joint venture private equity fund.