LONDON – Vale on Monday lost a bid to block fellow mining giant BHP Group's bid to have it share potential liability in a 36-billion-pound ($46-billion) London lawsuit over Brazil's worst environmental disaster.

More than 720 000 Brazilians are suing BHP, the world's biggest miner by market value, over the 2015 collapse of the Fundao Dam, which was owned and operated by the Samarco joint venture between BHP and Brazilian iron-ore producer Vale.

The disaster killed 19 people as more than 40-million cubic metres of mud and toxic mining waste swept into the Doce river, obliterating villages and reaching the Atlantic Ocean more than 650 km (400 miles) away.

BHP, which denies liability, applied in December to have Vale join the case and contribute to damages if they are found liable to the claimants.

The company argued that Vale should share in any potential liability because BHP Brasil and Vale both owned 50% of Samarco.

Vale challenged the jurisdiction of London's High Court to hear BHP's claim, arguing that any dispute between it and BHP should be heard in Brazil.

However, Judge Finola O'Farrell rejected Vale's challenge in a written ruling on Monday. She said BHP's claim against Vale essentially mirrored the claimants' case against BHP, meaning it should be decided as part of the existing lawsuit.

A BHP spokesperson said Monday's ruling would have no impact on the underlying case.

They also pointed to reparation and compensation programmes implemented by the Renova Foundation, a redress scheme established in 2016 by Samarco and its shareholders, which has funded more than $6 billion of rehousing, rehabilitation and indemnification for those affected by the disaster.

A Vale spokesperson said the company will "carefully consider" the court's ruling. They also said Vale "reaffirms its commitment to repairing the damage caused by the Fundao dam collapse", under agreements with the Brazilian authorities.

Tom Goodhead of law firm Pogust Goodhead, which represents the claimants, welcomed the decision.

"It's time for BHP and Vale to both do the right thing and to engage with the claimants in this case in order to affect an effective resolution," he said in a statement.