Slaughters out, HSF Kramer in on £36bn BHP Mariana dam case

HSF Kramer has replaced Slaughter and May as counsel to BHP in the Mariana dam litigation, the high-profile group action arising from the 2015 collapse of the Fundão dam in Brazil.

The move comes after a High Court ruling in November that found BHP liable for the dam collapse. BHP has said it will appeal the ruling.

Slaughter and May acted for BHP through the liability stages of the English proceedings. A spokesperson for the firm said: “We are not able to comment on the ongoing legal process, but BHP remains a longstanding and much valued client of the firm.”

BHP found liable

The High Court ruled that BHP was liable for the collapse of the Fundão dam, describing BHP’s failure to take adequate action despite the “overwhelming” evidence that the dam was unstable. That judgment, hailed as a major victory for the claimants, was secured by Pogust Goodhead.

The case has now transitioned to a damages assessment phase for the 600,000 Brazilian claimants, with the next trial scheduled for October 2026. The claim is valued at around £36 billion.

A marquee piece of litigation

The Mariana dam case has been closely watched for what it reveals about jurisdiction, group litigation and the expanding role of the English courts in large-scale overseas claims. 

HSF Kramer’s appointment places the firm at the centre of a dispute that continues to shape how multinational defendants manage risk and counsel strategy after adverse liability rulings, as cases move into complex damages phases.