The future of one of Nottinghamshire’s last collieries has been secured with the signing of a £200m deal.
Thoresby, which is owned by UK Coal, will supply EDF Energy with four million tonnes of coal by 2012.
Managers at UK Coal said the deal would allow a £55m investment programme which is expected to keep the pit open for at least another 10 years.
But the firm said the new seams would need fewer men, with about 100 of the 500 current jobs being axed.
Managers said there would be no job losses for two years and expected all of the redundancies to be through natural wastage.
Thoresby will supply EDF Energy’s Nottinghamshire power stations at Cottam and West Burton.
The value of the new deal has not been confirmed but is believed to be in the region of £200m.
In November, EDF Energy and UK Coal signed a two-year agreement to exploit the remaining reserves at Welbeck.