The Nottinghamshire-based firm UK Coal has signed a major deal with one of the country's biggest energy suppliers.
Three pits in the county will provide the bulk of the coal.
UK Coal already supply EDF Energy with coal for its plants at West Burton and Cottam, but this new deal secures an order worth £200m.
Most of the coal will come from pits at Welbeck, Harworth and Thoresby and be transported to the power stations by rail.
UK Coal is still waiting to find out if it is to get a share of a £60m government grant to safeguard the industry.
The company says this latest deal proves that coal is still a viable fuel.