ATH Resources, one of the UK's largest coal producers, has won a new sales contract to supply EDF Energy, one of the UK's biggest home and business energy suppliers, for 350,000 tonnes of coal.
The Doncaster-based company said the coal will be supplied at prices linked to international market indices.
Supply will commence immediately and end in December 2012.
Alistair Black, chief executive of ATH Resources, said: "This contract is an important development for ATH as it will increase average sales prices at the same time as the group continues to supply the remainder of its fixed price contracts.
The existing fixed price contracts that the group has in place will start to be phased out from March 2012."