Sydney (AFP) - BHP Billiton renewed its commitment Monday to do all it can to help following the deadly collapse of a waste water dam in Brazil, with the mining giant and partner Vale facing a huge lawsuit.The Brazilian government announced on Friday plans to sue the two companies for $5.2 billion in clean-up costs and damages after the November 5 collapse of the dam at the Samarco iron ore mine.BHP said in a statement it was aware of the development but had so far received no formal notice.The world's biggest miner added that "BHP Billiton confirms its commitment to supporting Samarco to rebuild the community and restore the environment affected by the breach of the dams".Brazilian Environment Minister Izabella Teixeira said a lawsuit would be filed demanding the companies and mine operator Samarco, which they co-own, create a fund of 20 billion reais ($5.2 billion).