The deadline for applications is 31 August and those who do not join will be entitled to a maximum of only about pounds 6,000 in the event of redundancy. About 9,000 mineworkers have joined.
Kevan Hunt, British Coal's employee relations director, said: 'It is important for all our employees to understand that those who transfer to a successor company do so on their terms and conditions at the time of transfer.
'It is a matter for those who have not signed to seriously focus their attention over the next few days. After that, it will be too late.'
The agreement, which must be honoured by the companies that buy British Coal, includes an immediate payment of pounds 6,000. However, mineworkers' unions are opposed to the scheme because it forces miners and colliery officials to accept more flexible working practices.
Mr Hunt said yesterday after meeting the unions on privatisation that about 2,000 more jobs were expected to go before British Coal was sold.
Most of the losses were likely to be among managers and clerical staff because of the sharp reductions in the mining workforce over the past few years.
British Coal employs about 14,000, although this includes 3,000 in businesses such as fuel distribution and consultancy.
In October 1992, when the Government announced the closure of dozens of pits, British Coal employed more than 50,000. Since then, the number of collieries has shrunk from 50 to 16.
The Government hopes to sell the collieries and opencast mines in up to five regional packages by the end of this year.Reuse content