Wakefield Council has pledged to support miners at Kellingley Colliery, which is expected to close within 18 months.
UK Coal is holding consultations with staff and unions on plans to shut the site, which employs 700 people.
Now, council leader Peter Box has pledged to support miners if the pit closes.
He said: “Our job now is to support those who face losing their jobs and do all we can as a council to put pressure on the government to help UK Coal and prevent these pit closures.”
Chris Kitchen, National Union of Mineworkers’ general secretary, said the union was told at a meeting on Tuesday the site would close by October 2015 at the latest, unless the government stepped in to support the firm.
He said: “It’s devastating for the people that are going to lose their jobs and I think it’s devastating for the country too.”
Joanne Roney, the council’s chief executive, said the authority was hoping to organise an advice day at the pit for the workers.
She said: “The loss of all these jobs is a big blow for the district. It is important that the mineworkers get the support they need to use their existing skills or retrain so they can take up new opportunities.”
Andrew Mackintosh, spokesman for UK Coal, said the firm hoped to secure £10m in investment to prevent the mine, along with a site at Thorseby in Nottinghamshire, from closing straight away.
He said: “It looks very dark days at the moment. What we are looking for with this funding is a managed closure over the next 18 months.”