Município de Mariana & Others v. BHP Group (UK) Ltd & BHP Group Ltd

Active Mass Tort / Class Action Mining £36B

The largest group claim ever tried in England: ~620,000 Brazilian claimants sued BHP’s parent companies over the 2015 Fundão (Mariana) tailings-dam collapse. In November 2025, the High Court found BHP liable under Brazilian law. Appeals against liability have been refused, and a quantum trial on claims put at up to £36B is listed for late 2027 into 2028.

On 11 September 2026, Mr Justice Constable rejected an application by Bailey Glasser International to stay the damages phase of the Mariana litigation pending resolution of the firm-representation dispute, ruling the case will proceed on its existing timetable toward a quantum trial now listed for April 2027. A public hearing to determine which firm, Pogust Goodhead or Bailey Glasser International, validly represents claimants is confirmed for 5-6 October 2026 before a different judge, and former Pogust Goodhead CEO Thomas Goodhead has joined Bailey Glasser’s team on the case.

On 5 November 2015, the Fundão tailings dam at the Samarco iron-ore mine, a 50/50 joint venture of BHP and Vale, collapsed, killing 19 people and sending mine waste down the Rio Doce to the Atlantic in what is often described as Brazil’s worst environmental disaster. Group proceedings issued in England in 2018 against the UK and Australian BHP parents were struck out as an abuse of process in 2020, reinstated by the Court of Appeal in 2022 and, after the Supreme Court refused BHP permission in 2023, went to a Stage 1 liability trial before Mrs Justice O’Farrell between October 2024 and March 2025. Shortly after the trial opened, BHP, Vale and Samarco signed a R$170B (≈US$30B) settlement with the Brazilian authorities, which BHP argued answered much of the English claim. BHP’s contribution claim against Vale settled separately on a 50/50 basis.

On 14 November 2025, in a 1,129-paragraph judgment ([2025] EWHC 3001 (TCC)), the court held BHP liable under Brazilian law, strictly, as a “polluter” under the Environmental Law, and on a fault basis under the Civil Code, and largely rejected its limitation defenses. O’Farrell J refused permission to appeal in January 2026 save on a single costs-interest ground, and on 6 May 2026 the Court of Appeal refused permission on every substantive ground, holding none reasonably arguable, while expediting the surviving costs appeal to around October 2026. The Stage 2 trial on causation and quantum, against claims the claimants value at up to £36B, is listed for the second half of 2027 into 2028, with individual entitlements to follow.

  1. SEP 11, 2026PROCEDURAL
    Court confirms 5-6 October 2026 hearing to resolve firm-representation dispute
    The High Court set a public hearing before a different judge for 5 and 6 October 2026 to determine whether Pogust Goodhead or Bailey Glasser International validly represents the Mariana claimants.
  2. SEP 11, 2026PROCEDURAL
    High Court rejects BGI’s bid to stay the damages phase pending representation dispute
    Mr Justice Constable dismissed an application by Bailey Glasser International to stay the Stage 2 damages proceedings while the fight over which firm represents claimants is resolved, ruling the litigation will continue toward a quantum trial listed for April 2027.
  3. SEP 4, 2026FILING
    Pogust Goodhead applies to High Court to challenge validity of its removal
    Pogust Goodhead filed an application seeking a declaration that the Client Committee lacked authority to terminate its retainer and transfer representation to Bailey Glasser International.
  4. SEP 2026OTHER
    Former Pogust Goodhead CEO Thomas Goodhead joins Bailey Glasser International
    Thomas Goodhead, former chief executive of Pogust Goodhead, joined Bailey Glasser International’s team pursuing the Mariana case, alongside newly retained barristers, as BGI seeks to be confirmed as claimants’ solicitors.
  5. AUG 28, 2026PROCEDURAL
    Client Committee purports to replace Pogust Goodhead with Bailey Glasser International
    The claimants’ Client Committee decided to terminate Pogust Goodhead’s retainer and appoint Bailey Glasser International (BGI), working with Hausfeld & Co LLP, as new solicitors of record. Pogust Goodhead disputes the Client Committee had authority to do so.
  6. MAY 6, 2026APPEAL
    Court of Appeal refuses permission on all substantive grounds
    [2026] EWCA Civ 502 (Lewison and Fraser LJJ, heard 12 March 2026): permission refused on all five substantive grounds as having no real prospect of success. The single surviving ground, interest on pre-judgment costs (permission granted by the trial judge), was expedited for hearing in around October 2026.
  7. JAN 19, 2026PROCEDURAL
    Trial judge refuses permission to appeal
    O’Farrell J’s consequentials judgment ([2026] EWHC 73 (TCC)) refused permission except on interest on costs. Claimants’ costs to that point were recited at about £189M net.
  8. NOV 14, 2025JUDGMENT
    BHP found liable
    [2025] EWHC 3001 (TCC): BHP held strictly liable as a polluter under Brazilian environmental law and liable in fault under the Civil Code. Limitation defenses largely rejected.
  9. OCT 7, 2024HEARING
    Stage 1 liability trial opens
    The trial ran to 13 March 2025 (about 50 hearing days) before Mrs Justice O’Farrell. Shortly after it opened, BHP, Vale and Samarco signed a R$170B settlement with Brazilian authorities.
  10. JUL 8, 2022APPEAL
    Court of Appeal revives the claims
    [2022] EWCA Civ 951 reinstated the group action. The Supreme Court refused BHP permission to appeal in 2023.
  11. NOV 9, 2020JUDGMENT
    Claims struck out
    Turner J struck out the claims as an abuse of process in light of parallel Brazilian proceedings and remediation schemes.
  12. NOV 2018FILING
    Group action issued in England
    Claims were brought against the UK and Australian BHP parent companies on behalf of a group that grew to roughly 620,000 Brazilian claimants.
  13. NOV 5, 2015OTHER
    Fundão tailings dam collapses
    The dam at the Samarco mine, a 50/50 BHP–Vale joint venture, failed, killing 19 people and polluting the Rio Doce for hundreds of kilometres to the Atlantic.