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Our commitment is to increase the safety of the communities where we operate and protect the environment. 

With that in mind, in 2019 we started a program to eliminate all our dams in Brazil that have an upstream method (backed on tailings). 

The process is technically called “de-characterization” and is established in current dam legislation. 

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And learn how these works are carried out and their importance for people's safety.

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Understand what it means

Check out the list and understand the meaning of some of the technical terms and expressions that we use in our daily work.

B

Belt channel / Peripheral channel

Channels built around the dams to prevent water, such as rainwater, from entering the dam. 


C

Center line dam

When the dam is expanded in stages, throughout its life, with overlapping dikes. 

Central drainage channel

It is a channel built, usually in stone, with the purpose of driving water out of the dam and preventing it from accumulating. 

Containment structure

A structure deployed below dams or dikes to retain the tailings in case of emergency and, in this way, reduce the impacts for the community and the environment. 


D

Dam

Structure used to contain sediment or store tailings and water.

DCE (Stability Condition Statement)

Mandatory document that proves the stability of a dam. Mining companies need to send the DCE to the National Mining Agency twice a year: in March and in September.

De-characterized structure

It is a dam that no longer poses any risk to the community, after undergoing works that eliminate its function of retaining tailings, water or sediment.

Decommissioning

This is when the operation of a dam is terminated. It is no longer operational.

Dike

A small dam. 

Downstream dam

Type of safe dam that is not extended over its tailings.

Drained piling

A method for depositing tailings, in which the material is arranged in a pile with an internal drainage system.


F

Floodgates

It is through them that we control the flow of water that passes through a containment structure. If there is an emergency at the dam, the gates are closed and the flow stops.

Flood spot

The picture of the region as it would look after the rupture of a dam. It takes into account the amount of material, the possible form of flow and the extent of the rupture.


G

Gabion

A structure used for dam reinforcement, land containment or drainage works. It is built with steel wire mesh and filled with stones.


I

Inlet / outlet

Place of water input (inlet) and output (outlet) of the spillway or overflow channel.

Iron ore tailings

Part of the ore production that is not processed (used). The material is not toxic, corrosive or flammable.


L

Lifeline

Protection implemented in the dam so that essential services can be performed safely by the worker. The system works by means of two metallic columns at the ends of the dam, interconnected by cables. The worker accesses the dam with a safety belt attached to the cables and can be removed from the site if necessary. 


M

Massif

The “body” of the dam. Usually built out of earth or concrete.

Monitoring

The permanent control and observation of the dam, through instruments, with the purpose of identifying and dealing with any change in structural conditions.


O

Overflow pipe / Spillway

A channel constructed to allow water left on the surface of the dam to drain off and keep the structure safer. It is usually made of concrete or stones.


P

PAEBM (Emergency Action Plan for Mining Dams)

Technical document prepared by the mining company defining immediate actions in cases of emergency with dams with the purpose of minimizing damage. The PAEBM identifies potential emergencies, establishes the actions to be carried out and defines the people and bodies that must be notified.

Pore pressure

The pressure exerted by the water from the reservoir on the structure of the dam. We monitor this pressure continuously to ensure the safety of structures.

Probing

Collecting a soil sample for study before carrying out engineering works.


R

Reservoir

Location of the dam used to contain water, sediment or tailings from ore processing.  

Rupture scenario

Emergency at the dam. For upstream structures that are at alert level 3, we have already erected tailing containments to increase protection for communities and the environment in the event of breakage. 


S

Safe access to the dam

Protection installed so that workers can access dams and can be safely removed from the site in the event of a structural emergency.

Safety Factor

Parameter used to quantify the stability of a dam.

Single stage dam

When the entire dam consists of a single dike, built in one go. 

Stable dam

When the dam's structure is intact and ready to operate.

Sump

A basin dug into the ground to contain sediment carried away by rain. It is used as one of the environmental control measures at construction sites.


U

Unmanned Equipment / Remote Operation

Truck, excavator, tractor or other equipment that operates without drivers in the cab, to ensure safety for workers during works on upstream dams. The professional operates the equipment through remote control, in a room equipped with cameras, far from the risk area of the dam.

Upstream dam

Type of dam that, when enlarged, has dikes supported on its tailings.

Upstream dam reinforcement

Structure built below the dam to increase its stability condition.


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2022

2021

2020

Containment structures

Whenever necessary, Vale built containment structures for some upstream dams to be eliminated and that present a higher degree of risk.  

Containment structures are built to protect communities and the environment in areas close to the de-characterization works of the Sul Superior (Barão de Cocais); B3/B4 (Nova Lima); Forquilhas I, II, III and Grupo (Ouro Preto-Itabirito) dams; and the Minervino and Cordão Nova Vista (Itabira) dikes. 

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Know the works by municipality

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Minas Gerais

Congonhas

Select one of the dams below for more information​

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Minas Gerais

Mariana

Select one of the dams below for more information​

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Minas Gerais

Santa Bárbara

Select one of the dams below for more information​

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Minas Gerais

Barão de Cocais

Select one of the dams below for more information​

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Minas Gerais

Rio Piracicaba

Select one of the dams below for more information​

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Click to see more


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Minas Gerais

Congonhas

Select one of the dams below for more information​

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Minas Gerais

Mariana

Select one of the dams below for more information​

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Minas Gerais

Santa Bárbara

Select one of the dams below for more information​

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Minas Gerais

Barão de Cocais

Select one of the dams below for more information​

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Minas Gerais

Rio Piracicaba

Select one of the dams below for more information​

Works schedule

We will eliminate 30 upstream structures by 2035, in order to ensure that ruptures like the one in Brumadinho does not happen again and we can be an increasingly safer company. Know the schedule:

Fotógrafo:

De-characterization status

  Click on the structures and see the deadline for completion of the work
Structure / City 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2035
Sul Superior Dam | Barão de Cocais​
Doutor Dam | Ouro Preto​
Campo Grande Dam¹ | Mariana
Xingu Dam | Mariana​
B3/B4² Dam² | Nova Lima
8B Dam | Nova Lima​
Vargem Grande Dam | Nova Lima​
Dike Auxiliar B5 | Nova Lima​
Fernandinho Dam | Nova Lima​
Grupo Dam | Ouro Preto​
Structure / City 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2035
Forquilhas I Dam | Ouro Preto
Forquilhas II Dam | Ouro Preto​
Forquilhas III Dam | Ouro Preto​
Baixo João Pereira Dam | ​Congonhas​
Área IX Dam | Ouro Preto​
Dike Minervino | Itabira
Dike Cordão Nova Vista | Itabira
Dike 2 Pontal Dam I Itabira ​
Dike 3 Pontal Dam | Itabira​
Dike 4 Pontal Dam | Itabira​
Structure / City 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2035
Dike 5 – Pontal Dam | Itabira​
Dike Conceição 1 A | Itabira
Dike Conceição 1 B | Itabira​
ED Vale das Cobras | Rio Piracicaba​
ED Monjolo | Rio Piracicaba​
Dike Ipoema | Itabira​
Dike Rio do Peixe | Itabira​
Dike 2 | Kalunga Dam ​
Dike 3 | Kalunga Dam​
Pondes de Rejeitos³ | Igarapé Bahia Dam

Engineering development/preliminary actions

De-characterization works in progress

Structures eliminated (de-characterized)​

Swipe right to check other structures

1 Campo Grande: Due to the need to implement instruments, probings and complementary engineering studies, the completion date for Campo Grande changed from 2025 to 2026.

2 B3/B4: Due to a higher-than-expected productivity achieved with unmanned equipment, the tailings conditions and the low impact of operations on the stability of the dam observed so far, in addition to a reduction in the volume of tailings to be removed, due to advances in studies of engineering, there is a trend for 2025.

3 Tailings Ponds: Completed in 2021 – Made official in 2022

Technology, innovation and safety

Unmanned equipment

Operation of vehicles remotely and outside the risk area, which increases employee safety.

Safe access to dams

Use of equipment to protect teams during activities in dam risk areas.

Remote probing

Remote operation of a rig to investigate the tailings and obtain geotechnical data from the structures.

Tailing disposal

Use of unmanned earthwork equipment (remote operation), allowing the dismantling of elevations and removal of material by dredgers (under study).

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Monitoring

Vale monitors its dams 24 hours a day, at the Geotechnical Monitoring Center, which ensures that these construction stages are carried out safely for all those involved in the works and the communities.

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Frequently Asked Questions

De-characterization is the act of intervening in the structure with the objective of making it completely lose the characteristics of a dam. At the end of the works, the structure is completely stable and is reincorporated into the relief and the environment. 

Decomissioning, in turn, is the initial stage of the de-characterization process, beginning with the confirmation that the dam is no longer necessary in the operational context of the enterprise and, therefore, may be deactivated or de-characterized. 

The tailings will be disposed of in exhausted pits and in sterile material and tailings stacks

Vale has been adopting all the necessary measures to increase safety and minimize the risks arising from interventions related to the de-characterization process. In the case of de-characterization works for dams, for example, alternatives are studied, such as the use of unmanned equipment (tractors, excavators, trucks, among other types of equipment) operated remotely; helicopter and cargo cable car to access risk areas. The goal is to not place people in risk areas.

It is important to emphasize that the de-characterization project aims to make the structure completely lose the characteristics of a dam. That is, at the end of the works, the structures will be totally stable and reincorporated into the relief and the environment. In some cases, residual tailings may remain, which will not compromise the stability of the land where the dam used to be. 
Yes. We regularly share announcements about the status of the works and new actions that will be initiated and measures to mitigate and reduce impacts for people. Dams in works with evacuated communities also have a calendar of meetings and visits to the works, established with representatives of the communities and the Prosecution Office of Minas Gerais. 

The elimination of upstream dams (on tailings or sediments) is a commitment made by Vale since the Brumadinho collapse in 2019, in addition to being a legal obligation. The rupture caused a change in the company's dam management to ensure more safety for its structures and communities and the De-characterization Program is one of the main milestones of this management effort, with the aim of ensuring that nothing of the sort ever happens again. The first structure eliminated was the 8B dam (Mina Águas Claras, in Nova Lima-MG), in December 2019. 

It is important to increase the safety of communities living in the vicinity of these structures and our operations. By losing the function of retaining water, tailings or sediments, the structure no longer poses a risk of accidents such as the one that occurred in 2019 at the B1 dam of Mina Córrego do Feijão, in Brumadinho. 

The communities located in the ZAS will remain outside their homes until the end of the work. When there is no longer any risk of the dams breaking, people can return if they wish. 

The process to eliminate a dam is complex and any intervention can entail increased risks. As a result, the company has already carried out several preventive actions, including the removal of all residents from the Self-Rescue Zones (ZAS) and the construction of containment structures below dams that are at a higher alert level, with the aim of reducing socio-environmental impacts in case of emergency. The works are carried out gradually, with constant monitoring and evaluation of the results, in order to reduce risks. If necessary, the activities shall be immediately interrupted. 

As the works are treated as emergencies, the projects can begin immediately, as established by law, with subsequent environmental regularization. Documents related to environmental regularization and respective studies are delivered to the environmental agency. 

In some cases, this will be possible. But we emphasize that the future use of the areas is a process that will take place with the progress of the discussions between the company, society and the Government.

The de-characterization or elimination of an upstream facility is a complex process and can take a long time to be completed, in order to be carried out with due care for safety. Each project has its own characteristics and challenges, and the safety of people and the environment is assumptions for all of them. All actions are monitored and supported by external consultants, authorities and technical auditors from public authorities.