A bid has been launched to track down former pitmen who paid into the Mineworkers pension Scheme (MPS) but have since "disappeared".
The MPS, which covers the majority of ex-miners, has about 140,000 deferred members who are due to receive a pension when they reach retirement age.
But about 33,000 of those have not provided up to date addresses for their benefits to be paid.
The MPS is appealing for former pitmen who may have entitlements to get in touch.
It has also joined a register operated by credit agency Experian which allows people to search for unclaimed financial assets.
David Morgan, chief executive of the MPS, said: "The aim is to help track down our missing members and verify their entitlements.
"We would also encourage anyone who believes they are a member of the MPS but who is not receiving our regular newsletter to contact our administration office."
The MPS has been the focus of controversy. With the lesser known British Coal Staff Superannuation Scheme (BCSSS), an agreement was struck by the Government to underwrite the schemes following privatisation of the coal mining industry.
The aim was to safeguard the funds against shortfall, but their performance outstripped expectations and during the 1990s large reserves built up to which the treasury takes a 50/50 split.
Talks between the Government and the trustees to review the agreement more favourably for members are due to take place after an application for a judicial review of the Government handling of one of the pension schemes was withdrawn earlier this year.
l The MPS can be contacted by calling (0845) 6064444.
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