South Africa's leading gold miners are facing a potential lawsuit on behalf of thousands of workers who claim they contracted silicosis, a lung disease, through the companies' negligence.

A South African lawyer filed the first papers on Tuesday against AngloGold Ashanti, Gold Fields and Harmony, in a preliminary step to determine whether the court recognizes the case as a class action.

"If the certification is granted we anticipate that this may be the largest damages suit in the history of this country, in the tens of billions of rand possibly," lawyer Charles Abrahams, who represents more than 3,000 mostly former miners, said.

The mining companies had declined to comment in detail ahead of the filing. A spokesman for Gold Fields said on Tuesday he would not comment, while officials at the other two firms were not immediately available.

The suit, which has little precedent in South African law, has its roots in a landmark ruling by the Constitutional Court a year ago that for the first time allowed lung-diseased miners to sue their employers for damages.

Silicosis is a disease that causes shortness of breath, a persistent cough and chest pains and makes people highly susceptible to tuberculosis, which kills. It has no known cure.

Abrahams said the claim was separate, but similar, to that of fellow lawyer, Richard Spoor, who represents several thousand more claimants. In March, Spoor said he would soon file his class action papers against the same mining companies cited by Abrahams.

The two cases could eventually be joined, said Abrahams.

Graham Briggs, the chief executive of Harmony, told Reuters earlier this year, the issue of silicosis was "a big topic" but he did not think it "class action material".

Different conditions prevailed at different times in different mines, he said, and workers may have had more than one employer.

A successful suit could collectively cost mining companies billions of dollars, according to legal and industry experts. The largest settlement to date by the mining industry in South Africa was $100 million in 2003 in a case brought by Spoor against an asbestos company.