However, in a twist, the Michael Zolotas-led company said it had pursued the deal despite a third party disputing the validity of the lease it has acquired.

NewLead has agreed to pay just $4m for the Viking Mine which independent appraisals indicate could contain up to 20 million tonnes of coal.

A separate reserve report compliant with the U.S. Securities and Exchange Commission (SEC) will be finalised by the end of the year, NewLead said in an exchange filing.

The