Rules-Based Mining: Lessons and Reflections from Brazil
Gemma James, Rory Sullivan and Sebastien Akbik
On 2 December 2025, Chronos, in partnership with the London Stock Exchange Group (LSEG), and the Global Investor Commission on Mining 2030 hosted an investor workshop with Vicente Mello, AECOM’s Brazil Country Manager, and members of his team.
Vicente’s presentation focused on AECOM’s role in the emergency response to Vale’s 2019 Brumadinho dam failure which resulted in 272 people being killed, and in the subsequent clean-up and reconstruction efforts. On behalf of the Public Prosecutor’s Office of the State of Minas Gerais, AECOM has been serving as the independent auditor for the socio-environmental initiatives established in the aftermath of the disaster. AECOM has also played a central role in the official response, audit, and development of tailings safety standards in Brazil.
Vicente described how the failure of the tailings dam at Brumadinho (and the earlier failure at Samarco in 2015) had raised fundamental questions for affected communities such as: Is our food safe to eat? Is it safe to drink the water? Can we give the water to our animals? Is it safe to return to my house? Is it safe for my children to go to school?
Systemic weakness
These failures also exposed systemic weaknesses in the internal governance of the mining companies involved, and in the regulatory agencies responsible for overseeing the safety of these facilities. These shortcomings prompted the Minas Gerais and Federal Public Prosecutors Offices to establish a special governance framework for the Judicial Agreements signed with mining companies and established an Independent Audit Program to confirm and assure companies complied with these obligations.
The failure of the Brumadinho tailings dam was the catalyst for global investor action on tailings. In the immediate aftermath of the dam collapse, global investors – convened by the Church of England Pensions Board – mobilised to call for the industry to disclose the number, construction method, and operational condition of tailings dams across all jurisdictions. This led to a global initiative, supported by the Principles for Responsible Investment (PRI), the United Nations Environment Programme (UNEP) and the International Council on Mining and Metals (ICMM), which developed and published the Global Industry Standard on Tailings Management (GISTM) in 2020. In 2025, the Global Tailings Management Institute (GTMI) started operating as the guardian of the GISTM, overseeing an independent conformance framework that will audit and disclose the level of compliance of mining companies to the standard.
Reflecting on Brazil’s experience in the wake of the Samarco and Brumadinho failures, Vicente and his team offered the following reflections:
Minas Gerais now has arguably the most robust tailings dam governance and regulatory framework of anywhere in the world
Brazil’s experience demonstrates that the transformation of the industry towards responsible tailings and mine waste management is feasible. The process requires time for changes in regulatory frameworks and governance systems, in standards, in auditing and verification processes, and in reporting.
Brazil’s experience shows that such a transformation is not purely a technical endeavour. AECOM’s team emphasised that technical changes, however challenging they can be, are not the hardest hurdle. The most difficult and important challenge remains cultural change at the company level; these cultural changes require strong, consistent support from senior management, significant organisational and governance improvements, and long-term commitment.
The experience with tailings dams is in stark contrast to that with hydropower dams. The reason that hydropower dams rarely fail is because they are treated as core assets and managed accordingly. In contrast, tailings dams are generally seen as waste-disposal facilities with the operational and financial focus being on the mining asset.
Chronos’ reflections
As the Secretariat to the Global Investor Commission on Mining, we see at first hand the role that institutional investors can play in supporting and enabling the transformation of the mining industry towards responsible mining. Investors have particularly important roles in:
Building consensus among stakeholders – companies, governments, the finance sector – on the need for high standards in the global mining industry.
Building partnerships to agree what these high standards look like, and then actively communicating these to mining companies and other actors along the mineral value chain.
Supporting regulatory changes conducive to responsible mining.
Ensuring that there is momentum behind the move to more responsible mining by joining multi-stakeholder initiatives such as the Global Investor Commission on Mining 2030.
To find out more about our work in the mining sector contact gemma@chronossustainability.com
Notes:
1. Vicente Mello, Senior Vice President at AECOM, is a technical and environmental expert and executive with over 30 years of experience leading complex projects in Brazil, Latin America, and Africa. He is a Commissioner on the Global Investor Commission on Mining 2030 and the Deputy Chair of the Global Tailings Management Institute. His expertise lies in environmental risk management, strategic planning and the implementation of high-complexity projects. Vicente led Brazil’s Independent Mining Audit Program, reporting to state and federal authorities on the response to the Fundão and Brumadinho tailings facility disasters. He led the Independent Technical and Environmental team to audit the Rio Doce Agreement between Vale, BHP, Samarco, and Brazilian authorities, the world’s largest environmental and social restoration agreement signed after the failure of a tailings dam. He also led the team which supported Brazil’s National Mining Agency in inspecting 229 high-risk dams and contributed to policy development for upstream tailings dam closure.
2. We would like to thank Vicente Mello and his colleagues Rafael Zanoni, Caio Prado, Rui da Justa Feijao Junior and Nasser Alessandro for their contributions to the discussion. We would also like to thank Adam Matthews (Church of England Pensions Board) and Jaakko Kooroshy (LSEG) for their responses to the presentation.
3. We would like to thank LSEG for hosting the meeting.
4. To read more about the Global Tailings Management Institute, see https://thegtmi.org/
5. To read more about the Global Investor Commission on Mining 2030, see https://mining2030.org/ The Commission is currently consulting on its priorities for action and on the role that individual stakeholders might play in turning the Commission’s Vision and Recommendations into reality. To find out more and to respond to the consultation, please see https://mining2030.org/consultation/
