The Government will not provide an extra £338 million to keep UK Coal's pits at Kellingley in North Yorkshire and Thoresby in Nottinghamshire open for a further three years, ministers have announced.
The decision confirms that the two pits will close by the end of the year, leaving one deep mine left in the UK, at Hatfield in South Yorkshire.
Business minister Matthew Hancock said committing public sector funding on the scale necessary to extend UK Coal's closure plan by three years was not affordable and did not represent value for money to the taxpayer.
"The £338 million requested approximates to a cost of more than £75,000 per UK Coal employee per year over the three-year closure plan," he said.
The minister added that the Government was prepared to provide additional funding to keep the closure plan on track.
UK Coal has asked for an extra £10 million so the closures can go ahead this year.
Mr Hancock said: "I can confirm that the Government is willing in principle to provide additional support to help deliver the plan, subject to conditions including state aid approval and appropriate support from other stakeholders.
"We are working with the company to determine the amount, timing and form this additional assistance could take."
TUC general secretary Frances O'Grady said: "Immediate help for UK Coal workers and their families is welcome, but this announcement doesn't resolve the long-term problems facing the UK coal industry, in terms of both job and energy security.
"The Government needs to find an alternative strategy that offers better energy and job security. Our EU competitors provide significant long-term state support for their mining industries, and here in the UK we should do the same."
Shadow energy secretary Caroline Flint said: "The Government's announcement has confirmed that Kellingley and Thoresby face imminent closure. Dithering and delays by ministers on support for these pits has meant that with every passing week the sum of money required has increased, and not enough has been done to support the workers to retrain and find employment.
"The Government must now turn its attention to the workforce and communities. We need to see a full package to support employment, and the economic and social needs of the communities in which these pits have played such an important role."