Thousands of miners with arthritis of the knee have won the right to take their compensation case to the next stage of legal proceedings.
Thousands of miners are fighting for compensation
Mining union Nacods said it had successfully applied for a group litigation order for the miners.
The union claims the knee problems are caused by years of repetitive work in cramped conditions.
The Department of Trade and Industry (DTI) said there was no evidence yet it was liable for the knee injuries.
Bleddyn Hancock, from Nacods south Wales, said: "We are delighted our application has succeeded so we can take this case to the next level.
"We can now proceed to have access to the British Coal documents that are in the possession of the Department of Trade and Industry."
"We hope to complete our investigation of these documents as quickly as possible, as we are very aware that many of these miners with severe knee injuries are elderly men and time is of the essence."
The application for a group litigation order was made in Leeds County Court in May 2006.
Solicitor Gareth Morgan, who is acting for Nacods, said he expected there would be another court hearing for directions on how the action would proceed, including a register of possible complainants.
A DTI spokesperson said: "A group litigation order has only recently been granted by the Lord Chief Justice.
"Therefore, this proposed litigation is still in its infancy and at present, no evidence has been produced to suggest that any liability attaches to the DTI for the knee injuries."
In March 1999, the UK government agreed to pay about £1.5bn damages to 65,000 former miners suffering from lung diseases.
It was the UK's largest industrial injury compensation payout.