Hundreds of jobs could be at risk at Kellingley Colliery even if operators UK Coal manage to secure urgently needed investment.
The coal mining firm, which also runs seven other pits across the country, said it hoped to secure at least £10m of investment within weeks but added that it would not guarantee the future of any jobs.
Andrew Mackintosh, UK Coal’s director of communications, said: “We are seeking some external investment to try and find the best way forward for the business.
“It’s extremely important we get it but, even if we do, the business will need to reviewed.
“There is definitely some uncertainty about the future. It all depends on how the talks conclude.”
Kellingley, which has 700 workers, was saved from closure in July last year after pit bosses struck a deal with a pension and rescue fund.
The Express launched a petition in May to help save the Weeland Road site from closure, which was backed by the community, workers and politicians.
Mr Mackintosh said the latest financial difficulties were down to the cheap price of coal and the strength of the pound against the dollar.
He added: “Most of our contracts are done in dollars and the exchange rate has really affected us.
“Cheap coal is great for people in terms of the cost of their energy bills but it’s not so good when you are trying to sell coal.”
Yvette Cooper, MP for Pontefract and Castleford, said: “Kellingley is really important - both for jobs in our area and for our national energy supply.
“That’s why I’ve urged the energy minister to do everything possible to support our pits and local miners.
“Our area has a proud history of mining, and I’m working with the NUM to keep the pressure on to support Kellingley jobs.”