Gold mining firms will appeal against a court ruling allowing class action suits seeking damages for up to half a million miners who contracted the fatal lung diseases silicosis and tuberculosis, a lawyer for the miners said on Friday. A High Court decision last month set the stage for protracted proceedings covering cases dating back decades in the largest class action suits yet in Africa's most industrialised country. Anglo American , Africa's top gold producer AngloGold Ashanti, Gold Fields, Harmony Gold, Sibanye Gold and African Rainbow Minerals, have formed the Occupational Lung Disease (OLD) group to deal with such issues. The group confirmed that the companies had filed individual applications to appeal the class certification judgment handed down on May 13, adding that the firms have been seeking a settlement with the affected workers."Whilst the companies deny liability for the claims, it is nonetheless the working group's view that a fair and sustainable settlement is preferable to long and protracted litigation," the OLD said in a statement, adding that the discussions have been going for more than a year.Charles Abrahams, an attorney who acted on behalf of the miners, had told Reuters in Cape Town that the companies planned to appeal the court ruling.Silicosis is an incurable disease caused by inhaling silica dust from gold-bearing rocks. It causes shortness of breath, a persistent cough and chest pains, and also makes people highly susceptible to tuberculosis.The court had estimated that more than half a million claimants could be involved in the cases against the firms."Assuming a conservative claim of $6,500 (R101,238) per claimant, this approximates claims in the total amount of $3.25 billion," said Max Ebrahim, an insurance partner at law firm Clyde & Co. ..