London (AFP) - A trial to determine whether Australian mining giant BHP is liable for one of Brazil’s worst environmental disasters opened Monday in London, potentially triggering billions of dollars in compensation to be shared among hundreds of thousands of people.

The High Court in the British capital will examine over several months whether BHP is partly liable for the 2015 collapse of a dam at a mining waste site in Brazil.

The rupture killed 19 people and unleashed a deluge of thick toxic mud into villages, fields, rainforest, rivers and the ocean.

The Fundao tailings dam at an iron ore mine in the mountains of Minas Gerais state was managed by Samarco, co-owned by BHP and Brazilian miner Vale.

At the time of the disaster, BHP had global headquarters in Britain and Australia.

A separate case in Brazil has seen Vale and BHP offer to pay almost $30 billion in compensation. This was increased on the eve of the London trial from almost $25 billion.

The amount of damages sought in the London civil trial is estimated at £36 billion ($47 billion), on behalf of more than 620,000 plaintiffs, including 46 Brazilian municipalities, companies and indigenous peoples.

- ‘Justice?’ -

“It’s nearly nine years on now and no one has been held accountable,” Tom Goodhead, of law firm Pogust Goodhead which brought the case, told AFP outside the court.

“Whilst this isn’t a criminal trial, it acts as a way of holding the company liable and accountable,” added Goodhead, who was joined by relatives of victims.

“Will they get justice?” read a banner which showed photos of those killed.

The tragedy in the town of Mariana unleashed almost 45 million cubic metres of highly toxic mining waste sludge, flooding 39 towns and leaving more than 600 people homeless.

The flood killed thousands of animals and devastated protected tropical rainforest.

“It’s been really difficult these last nine years but I have to be strong,” said Gelvana Rodrigues outside court. Her seven-year-old son, Thiago, was killed following the dam’s collapse.

“My hope is to find justice here. In Brazil, it is hopeless.”

- First stage -

The hearing, set to last until March, must determine BHP’s potential liability for the disaster.

If it is ruled liable, another trial would take place from October 2026 to determine the damages.

BHP has said the London case is unnecessary because of ongoing legal procedures in Brazil.

In opening submissions to the court Monday, the company laid out as a central argument that it “did not own or operate the dam or any related facilities”.

The company estimated that more than 200,000 plaintiffs in the London case had already been compensated.

BHP added that the Renova Foundation, which manages compensation and rehabilitation programmes, has already paid out more than $7.9 billion in emergency aid.

The Australian mining giant said the quality of river water contaminated by the fallout has returned to pre-disaster levels.

However, a scientific paper published this year in the Franco-Brazilian geography review Confins said the dam rupture had caused “permanent effects of pollution” on the river Doce and its coastal plain.

In 2019, another tailings dam owned by Vale collapsed in Minas Gerais, killing 270 people and devastating the surrounding environment.

The London trial opened as BHP weighs whether to mount a renewed bid for British rival Anglo American. One $49 billion takeover was rejected in May.

BHP is allowed to come back with a fresh offer on November 29 following a six-month break, according to UK rules.

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