The Journal reported that the parties are expected to strike an agreement in the next few days that would see the companies cover public damages from what’s considered Brazil’s worst-ever environmental disaster.

In early November, the Samarco Fundão dam that held back tailings from a giant iron ore mine operated by Brazilian company Vale (VALE) and Australia’s BHP Billiton (BHP) gave way, killing 17 people and spilling 20,000 Olympic swimming pools worth of toxic mud into the soil, rivers, and water systems of an area covering 850 kilometers. Experts from the United Nations documented the extensive damage in a report in late November and found that the companies’ preventative measures were “clearly insufficient.” The toxic sludge from the dam made its way down the Doce, one of Brazil’s biggest rivers, and toward the Abrolhos National Marine Park that contains protected forest land and habitat.

Once reached, the deal will settle a $5 billion civil lawsuit that Brazil’s attorney general filed against Vale, BHP Billiton, and the miner they own jointly, Samarco Mineração. The agreement is expected to cover the social and environmental consequences of the dam breach, but it won’t address the ongoing criminal investigations against Samarco and Vale for environmental crimes and manslaughter, fines from state and federal regulators, or any private lawsuits, the Journal says.

The terms of the settlement will require the companies to rebuild the community of Bento Rodrigues where 82% of the buildings were buried by the accident and restore about 400 miles of river in the Doce basin that were flooded by mud and heavy metals. The companies will also have to cooperate with government agencies to document surviving species in the river, the Journal reports. Some 10 fish species were already endangered before the dam burst. If those fish can’t be located now, the companies will have to pay additional costs.