UK Coal is set to close Kellingley colliery in North Yorkshire and Thoresby colliery in Nottinghamshire by 2015.
The National Union of Mineworkers told the BBC redundancy letters had been posted to 57 Kellingley workers and about 270 Thoresby workers.
"I can't see it's in anybody's interests to issue redundancy notices to anybody today, given that the company doesn't even know if they've got the financing in place for their 18-month closure plan," NUM general secretary Chris Kitchen told BBC reporters.
The government offered UK Coal a loan of £10 million ($A18 million) in order to execute an 18-month planned closure of the mines.
However, NUM is looking into an employee buyout of the Kellingley colliery.
NUM believes the pits are performing better than expected and therefore the redundancies can be put on hold, giving time for a rescue package effort, whether it is state-aid or an employee buyout.
UK Coal blamed its financial problems on falling coal prices in the global market, on top of a fire that destroyed and subsequently closed its Daw Mill colliery in Warwickshire.
