A long-awaited trial into whether Australian miner BHP is liable for one of Brazil's worst environmental disasters opens in London on Monday, potentially triggering compensation totalling billions of dollars.
The High Court in London will over several months examine whether BHP was in part responsible for the collapse in 2015 of a tailings dam in Brazil that killed 19 people and caused huge damage to the environment.
The tragedy in the southeastern town of Mariana unleashed a torrent of almost 45 million cubic metres of highly toxic mining waste sludge, flooding 39 towns and leaving more than 600 people homeless.
The flood also killed thousands of animals and devastated protected areas of tropical forest.
The collapsed dam at an iron ore mine was managed by Samarco, co-owned by BHP and Brazilian miner Vale.
At the time of the disaster, BHP had global headquarters in the UK as well as in Australia.
A separate case in Brazil has seen Vale and BHP offer to pay almost $25 billion in compensation. Vale has offered to share any compensation BHP ends up paying as a result of the London trial.
Tom Goodhead, of law firm Pogust Goodhead that is bringing the case, told a news conference on Wednesday that the London trial was the culmination of a six-year legal battle in Britain.
"For a lot of the clients that we represent, this is their opportunity for accountability and for justice, putting aside any of the financial damage or the environmental damage which has been caused."
The amount of damages sought in the upcoming civil trial is estimated at GBP36 billion ($47 billion), on behalf of more than 620,000 plaintiffs including 46 Brazilian municipalities, companies and Indigenous peoples.
"Such a thing cannot go unpunished," said Pamela Rayane Fernandes de Sena, whose five-year-old daughter Emanuele Vitoria was killed in the tragedy.
Speaking to AFP ahead of the trial, the 30-year-old said she was "not here for the money but to bear witness" to Emanuele's life, adding that she wished to remain "firm and strong" to obtain "justice".
"So I'm not going to give up," she said, calling the trial in London "(her) only hope".
The hearing, set to last until early March, must determine BHP's potential liability surrounding the disaster.
If found liable, another UK trial should take place from October 2026 to determine the amount of damages.
BHP argues the London court case is unnecessary because of the ongoing trial in Brazil.
The company estimates that more than 200,000 plaintiffs in the London case have already been compensated.
BHP adds that the Renova Foundation, which manages the compensation and rehabilitation programmes, has already paid out more than $7.8 billion in emergency financial aid.
The Australian giant additionally insists that the quality of river water contaminated by the fallout has returned to pre-disaster levels.
