07/05/2026

Court of Appeal rejects BHP appeal attempt in landmark Brazilian dam case

In the latest milestone in the Mariana Dam litigation, described by Fraser LJ as the “very definition of a heavy case”, BHP has failed in its application for permission to appeal the November 2025 judgment of O’Farrell J.

The Court of Appeal had taken the unusual step of directing an oral hearing before a two-person panel (Lewison and Fraser LJJ). Having heard argument and reserved judgment, it went on to reject BHP’s application in unusually robust terms. See: Municipio de Mariana & Ors v BHP Group (UK) Ltd & Anor [2026] EWCA Civ 502.

Andrew Fulton KC acted for the claimants, who were respondents to the application for permission to appeal.

Judgment

BHP had sought permission to appeal under five grounds. In relation to the two causes of action and three attempted limited defences on which BHP had lost at trial, BHP complained that the judge had arrived at the wrong outcome and/or adopted an approach which was procedurally unjust. As Fraser LJ observed at [24], the grounds and sub-grounds gave rise to “potentially 14 different points upon which the trial judge is said simply to have failed to engage with the case advanced by BHP”.

The Court of Appeal rejected all these grounds and sub-grounds, emphasising by reference to Perry v Lopag [2023] UKPC 16 the limited scope for an appeal court to interfere in first-instance findings of fact. The bar is particularly high where those findings concern not merely foreign law but the unfamiliar law of a civil code country in relation to which the first-instance judge will have been assisted by the parties’ experts “not only with their opinions on the texts but also the meanings and nuances of language”.

In relation to BHP’s allegation that O’Farrell J’s failure to mention specific arguments or aspects of the evidence justified the re-opening of her findings, the Court of Appeal emphasised that Volpi v Volpi [2022] EWCA Civ 464 at [2](iii) required an appeal court to assume “unless there is compelling reason to the contrary” that the whole of the evidence at trial has been taken into consideration. BHP had sought to reverse that approach by assuming that points not specifically dealt with may have been overlooked or misunderstood by the judge.

The Court of Appeal was not therefore deterred by the scale and financial value of the litigation from applying established principles of appellate restraint.

The Stage 2 trial, to address questions of causation and quantum in relation to a selection of lead claimants, will commence in April 2027.

Andrew Fulton KC was instructed by Pogust Goodhead, alongside Alain Choo Choy KC of One Essex Court and Jonathan McDonagh of Serle Court.