This website was created to share the report of the Fundão Tailings Dam Review Panel (the “Panel”). The Panel was constituted by Cleary Gottlieb Steen & Hamilton LLP (“Cleary Gottlieb”) which was retained jointly by Samarco Mineração S.A. (“Samarco”) and its shareholders, BHP Billiton Brasil Ltda. (“BHP Billiton”) and Vale S.A. (“Vale”), to conduct an investigation to determine the immediate cause of the November 5, 2015 Fundão tailings dam (“Fundão Dam”) failure. The Panel members are Norbert Morgenstern, Steven G. Vick, Bryan D. Watts and Cássio Viotti, who have decades of geotechnical expertise, which they brought to bear in the months since this highly complex investigation began.

The Panel produced the report to Cleary Gottlieb in accordance with its terms of reference exclusively for and at the request of Cleary Gottlieb. Under the terms of reference, the Panel was required to provide its independent and unbiased professional judgment and expertise in connection with the technical analysis undertaken. The report does not necessarily represent the views of any of Samarco, BHP Billiton, or Vale or any individual or entity other than the Panel. It has not been prepared in response to any third party investigation, inquiry or litigation.

Cleary Gottlieb and the Panel were given full access to Samarco’s documents, employees and facilities, and the Panel had the documents and information necessary to determine the immediate cause of the failure of the Fundão Dam.

Documents and information were obtained from the following parties:

Samarco: Samarco is the Brazilian mining company that owns and operated and managed the Fundão Dam.

Joaquim Pimenta of Pimenta De Avila Consultoria Ltda.: Mr. Pimenta served as the designer and engineer of record from the initiation of the Dam until 2012, and consultant thereafter.

Members of the Independent Tailings Review Board (“ITRB”): The ITRB was a panel of external experienced technical advisors engaged by Samarco from 2009 onward to review and provide advice on its tailings structures, including the Fundão Dam.

VogBR Recursos Hídricos e Geotecnia Ltda.: VogBR was involved in the design of drainage structures and conducted seepage and stability analyses of the Dam.

Integral Engenharia: Integral was involved in the construction of certain drainage structures on the Dam.

GeoFast Centro de Treinamento: GeoFast was involved in the creation of risk assessment parameters for the saturation conditions on the Dam.

Geoestável Consultoria e Projetos: Geoestável conducted hydrogeological studies on the Dam in connection with the project to raise the Dam to an elevation of 940 meters.

DAM Engenharia: DAM conducted seepage and stability analyses in connection with the project to raise the Dam to 940 meters.

NouH Engenharia: NouH designed the process for repairs to certain drainage structures on the Dam.

The Panel’s technical analysis included, among other things, (i) building of a 3D computer model of the entire tailings facility over time, (ii) in-depth analyses of the tailings deposited in the Fundão Dam in order to understand their properties and behaviors, (iii) analyses of levels of saturation in the Fundão Dam and the flow of water through it over time and (iv) testing to understand the role that earthquakes may have played in the collapse of the Fundão Dam.

The Panel did not evaluate documents and information against legal standards, including but not limited to standards regarding liability, intent and the admissibility of evidence in court or other proceedings. The Panel did not seek documents and information related to fault or responsibility nor did they endeavor to assign fault or responsibility to any person or party, to evaluate whether or not the failure could have been foreseen or prevented, or to gauge environmental or other downstream effects or damages of the Fundão Dam failure.

The Panel assessed and interpreted historical documents and information with the benefit of knowledge learned from intervening events. Thus, the Panel’s findings and conclusions do not imply, and it should not be inferred, that the same findings and conclusions could have been drawn at the time of the events in question. The Panel did not address that question.

At times, the information available to the Panel was inconsistent, unclear or uncorroborated. The Panel did not seek to make credibility determinations in such cases. In evaluating the information available to it, the Panel used its best professional judgment, but recognizes that others could reach different conclusions or ascribe different weight to particular information.

The report should be read as a whole, and individual passages should be viewed in the context of the entire report, including the appendices, which are an integral part of the report. Discussion or analysis that is based, to any extent, on work carried out by third parties – for example, on field or laboratory work commissioned by the Panel – is subject to the same qualifications or limitations to which that work was subject.

In the report, graphics are used to depict information, locations and events. These graphics may be simplified or not to scale and are intended only as an aid to the reader in the context of the discussion that they support.