The coal giant started the sale process for the mine in January this year following its successful $4.9 billion takeover of Macarthur Coal.
According to The Australian, the Thai company is in the process of reviewing data on the mine in the lead-up to the April 23 deadline on non-binding preliminary offers.
The news service said PTT’s attraction to the asset formed part of the company’s aim to increase coal output to 30 million tonnes over five years, up from 3Mt in 2010.
Peabody acquired Wilkie Creek in 2002.
The mine produces more than 2 million tonnes per annum of thermal coal.
Peabody appointed UBS to manage any possible sale of the asset.
A sale of the mine could reportedly go for between $500 million and $750 million.