1. Dam raising
The process of increasing a dam’s height to expand its storage capacity. It can be carried out using the upstream, downstream, centerline or single-stage method.
Downstream
The embankment is constructed away from the reservoir, that is, in the direction the water or tailings flow after passing through the dam.
Upstream
The raised embankments are supported by previously deposited tailings or sediment. Construction progresses toward the reservoir.
Centerline
The embankment is constructed away from the reservoir, that is, in the direction the water or tailings flow after passing through the dam.
Single Stage
The dam is constructed to its full height from the outset, with no subsequent raises.
2. Dam or Dike
A structure built to store tailings, sediment or water associated with mining operations. Dams that store tailings may also be referred to as tailings storage facilities (TSFs).
3. Declaration of Stability Condition (DCE)
A technical document required under Brazilian regulations, certifying that a dam is stable.
4. Decharacterization
5. Engineer of Record (EoR)
An independent external professional responsible for continuously reviewing and interpreting data generated through inspection and monitoring activities throughout the life cycle of structures.
6. Downstream containment structure
A structure built downstream of a dam to retain material resulting from potential dam failures or operational incidents, helping protect lives.
7. Independent Tailings Review Board (ITRB)
An independent multidisciplinary panel of internationally recognized experts appointed to provide Vale with technical opinions and recommendations regarding its structures.
8. Emergency Level
A classification established by Brazil’s National Mining Agency (ANM) to grade potential emergency situations that could compromise dam safety. Emergency levels range from 1 to 3, with Level 3 being the most critical.
9. Mining Dam Emergency Action Plan (PAEBM)
A document required under Brazilian regulations that establishes the procedures and responsibilities to be followed in the event of a dam emergency.
10. Tailings
Materials generated during ore processing, typically consisting of fine particles and water. In some cases, tailings may be reused in the future.
11. Sediments
Solid materials transported and deposited by water or other natural agents. These materials are contained by structures such as dams and dikes to prevent environmental and operational impacts.
12. Operational Status
The stages in a geotechnical structure’s life cycle: Design, Construction, Operation, Inactive, Under Decharacterization and Decharacterized.
13. Self-Rescue Zone (ZAS)
The area immediately downstream of a dam where there is insufficient time for emergency response by the public authorities.
14. Secondary Safety Zone (ZSS)
The area beyond the Self-Rescue Zone, where there is sufficient time for the public authorities to respond and implement evacuation plans in the event of a dam emergency.
FAQ
Decharacterization is the process of transforming a structure so that it completely loses its characteristics as a dam. Once the work is completed, the structure is fully stabilized and reintegrated into the surrounding landscape and environment.
Decommissioning is the initial stage of the decharacterization process. It begins once it has been confirmed that the dam is no longer needed for the operation and can therefore be deactivated or decharacterized.
The tailings will be relocated to depleted mine pits and waste rock and tailings piles.
Vale is taking all necessary measures to enhance safety and minimize the risks associated with decharacterization activities. For example, alternatives such as remotely operated unmanned equipment (including bulldozers, excavators and trucks), as well as helicopters and aerial cableways for accessing high-risk areas, are being used where appropriate. The goal is to avoid exposing people to hazardous areas.
It is important to emphasize that the objective of decharacterization is for the structure to completely lose its characteristics as a dam. In other words, once the work is completed, the structure will be fully stabilized and reintegrated into the surrounding landscape and environment. In some cases, residual tailings may remain, but they will not compromise the stability of the area where the dam once stood.
Yes. We regularly share updates on the status of the projects, upcoming activities and measures to mitigate impacts on people. For dams undergoing decharacterization where communities have been evacuated, we also maintain a schedule of meetings and site visits agreed upon with community representatives and the Minas Gerais State Public Prosecutor’s Office.
Vale has been committed to eliminating its upstream dams (built over tailings or sediments) since the Brumadinho dam failure in 2019. In addition to being a legal requirement, this commitment reflects the changes the Company made to its dam management practices to enhance the safety of its structures and surrounding communities. The Decharacterization Program is one of the main pillars of this effort, with the goal of ensuring that a tragedy like Brumadinho never happens again. The first structure to be eliminated was Dam 8B at the Águas Claras mine in Nova Lima, Minas Gerais, in December 2019.
Eliminating upstream structures helps enhance the safety of communities located near these structures and our operations. Once a structure no longer serves to retain water, tailings or sediments, it no longer poses the risk of accidents such as the failure of Dam B1 at the Córrego do Feijão mine in Brumadinho in 2019.
Communities located within the Self-Rescue Zone will remain evacuated until the work has been completed. Once there is no longer any risk of dam failure, residents may return to their homes if they choose to do so.
Because these are emergency projects, they may begin immediately, as permitted by law, with the required environmental approvals obtained afterward. The required documents and supporting studies are then submitted to the environmental authority.
In some cases, yes. However, future use of these areas will depend on ongoing discussions involving the Company, society and the public authorities.
Decharacterizing or eliminating an upstream structure is a complex process that can take considerable time to ensure it is carried out safely. Each project has its own characteristics and challenges, but all are guided by the fundamental principle of protecting people and the environment. Every project is monitored and supported by external consultants, the public authorities and their technical auditors.
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