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nexa

Dams and Tailings Deposits

Nexa stores industrial tailings and waste using technologies such as dry stacking, returning to the mine, and dams.
Learn more about how we operate, and our safety management system for geotechnical structures.

Dry stacks and deposits

One of the alternatives to disposing of mining tailings is to deposit them in dry stacks.
Find out more about the dry stacking method and our safety management systems.

New technologies and Backfilling

Nexa is concerned with the environment and sustainability, so we apply new technologies to reutilize mine tailings, reusing them as by-products and backfill (returning the material to the mine).
Learn more about the dry stacking method, as well as our safety management systems.

Dams

One of the methods used by Nexa is to deposit tailings in dams, preferably built in a single stage, or with downstream or centerline raising.
Learn more about the tailings dam method and our safety management system.

Highlights

Sirens

In 2019 we installed the most modern siren system in the areas of the Self-Rescue Zone*, with a sound intensity of 70 dB, at all units in Brazil, in the metallurgy and mining sectors.

Emergency Drills

In the localities where Nexa operates, we carry out emergency drills jointly with the local community, civil defense officials, military police and fire departments.

Reuse of Tailings

In Morro Agudo, we transformed all the tailings into a secondary product, Agricultural Limestone Powder, from which Zincal200 is derived.

Nexa

A Nexa
Who we are

We are Nexa. We’ve changed to go further. To extract deeper, to mine with greater responsibility, to build a more valuable future. A company that believes that mining is the basis for society to evolve. The key ingredient that will sustain the essence of the products and services that we need to develop.

Nexa’s dams and tailings deposits

Dams and tailings deposits are one of the main risks associated with mining activity. We control and monitor the 47 structures (24 in Peru and 23 in Brazil), following the best international practices and the laws in force in each country where we operate.

Nexa prioritizes the reuse of materials through new technologies, as an alternative in the treatment of tailings and waste. This proposal is applied at the Morro Agudo Mine, where tailings are a commercially viable by-product. When this is not applicable, Nexa uses three different forms of disposal, preferably returning the material to the mine (backfill), secondly by dry stacking, and – when these solutions are not possible – we dispose of them in dams. Currently, roughly 15% of the tailings/waste generated by Nexa in Brazil and Peru is disposed of in dams.

Some operations may combine one or more disposal methods. At the Atacocha, El Porvenir and Cerro Lindo units in Peru, we adopted the backfill system, whereby 46% of the tailings are returned to the mines at the Pasco Complex (Atacocha and El Porvenir), and 38% is returned to the Cerro Lindo mine, in which part of the waste is filtered, separating water and solids. The water is recirculated and the filtered tailings are sent to the dry stacks to be compacted.

In Brazil, we already operate in the Vazante mine, disposing of the tailings in dry stacks, which reduces environmental impacts and risks to the operation. This same model will be adopted in the Aripuanã operation, still under construction.

Backfill
source: www.tailings.infostoragebackfill.htm

Backfilling refers to filling the mine with tailings, inserted into the voids of underground mines, for the purpose of increasing the structural stability of the mine, providing platforms, improving ore recovery, and disposing of tailings.

The underground disposal of tailings in mining pits can only occur when the tailings are considered inert, eliminating the possibility of contaminating water or soil.

Depósito a seco

Also called a filtered (or dewatered) tailings stack/deposit, the pulp tailings that remain after processing the ore undergo filtering, drying and handling (whether combined or single method), until obtaining moisture content below 20%.

By extracting water from the pulp (the mixture of liquid plus ore or tailings), the solid part is stored or placed in stacks, ensuring reduced environmental impact.

Barragem

A dam is a structure built for the purpose of containing, impounding or storing water, liquid substances, or mixtures of liquids and solids, whether permanently or temporarily.

The term “dam” comprises not only the levee or embankment itself, but also all associated structures, such as: spillways and sluices, reservoir, headrace, diversion structures, tailrace, water intakes, impoundment intakes, saddle dike, among others.

Status of dams and tailings deposits

The disposal of waste in NEXA for several alternatives, but all of them meet the best practices and technologies available. Below, you can view the status of the structures (dam, pound and reservois) at each site and the construction method used for each one.

Brasil

DAMS AND TAILINGS DEPOSITS IN BRAZIL

Brasil
Peru

DAMS AND TAILINGS DEPOSITS IN PERU

Peru
Legendas
Consolidated
Consolidado

Data and documents

Dams and tailings deposits
Pedra Dam
Structure Purpose Structure type Operation Startup Embankment Raising Method Number of Embankment Raises Operational Status Construction Method
Pedra Dam Industrial tailings Dam 2008 In stage 1 Active Centerline Raising

Geotechnical Evaluation Download Download Brasil (Only portuguese)
Technical Report on Water Quality and Dust Download Download Brasil (Only portuguese)
Emergency Action Plan Download Download Brasil (Only portuguese)

Peixes Dam
Structure Purpose Structure type Operation Startup Embankment Raising Method Number of Embankment Raises Operational Status Construction Method
Peixes Dam Industrial tailings Dam 1998 Continuous 8 Inactive Centerline Raising

Geotechnical Evaluation Download Download Brasil (Only portuguese)
Technical Report on Water Quality and Dust Download Download Brasil (Only portuguese)
Emergency Action Plan Download Download Brasil (Only portuguese)

Abraço Pond

Under construction

Valtencir Pond

Under construction

Sapo Pond

Under construction

Reservoir Dike III

Under construction

Reservoir 2AB

Under construction

Esperança Reservoir

Under construction

Índio / José Jaime Reservoir

Under construction

Reservoir IV

Under construction

Dam 01
Structure Purpose Structure type Operation Startup Embankment Raising Method Number of Embankment Raises Operational Status Construction Method
Dam 01 Mining tailings Dam 1988 In stage 0 Active Single Stage

Geotechnical Evaluation Download Download Brasil (Only portuguese)
Technical Report on Water Quality and Dust Download Download Brasil (Only portuguese)
Emergency Action Plan Download Download Brasil (Only portuguese)

Dam 02
Structure Purpose Structure type Operation Startup Embankment Raising Method Number of Embankment Raises Operational Status Construction Method
Dam 02 Mining tailings Dam 2006 In stage 1 Active Centerline

Geotechnical Evaluation Download Download Brasil (Only portuguese)
Technical Report on Water Quality and Dust Download Download Brasil (Only portuguese)
Emergency Action Plan Download Download Brasil (Only portuguese)

Dam 03
Structure Purpose Structure type Operation Startup Embankment Raising Method Number of Embankment Raises Operational Status Construction Method
Dam 03 Mining tailings Dam 2010 In stage 0 Active Single Stage

Geotechnical Evaluation Download Download Brasil (Only portuguese)
Technical Report on Water Quality and Dust Download Download Brasil (Only portuguese)
Emergency Action Plan Download Download Brasil (Only portuguese)

Settling Basin
Structure Purpose Structure type Operation Startup Embankment Raising Method Number of Embankment Raises Operational Status Construction Method
Settling Basin Sediments Dam 2017 In stage 0 Active Single Stage

Emergency Action Plan Download Download Brasil (Only portuguese)

Safety Dike
Structure Purpose Structure type Operation Startup Embankment Raising Method Number of Embankment Raises Operational Status Construction Method
Safety Dike Industrial tailings Dam 1983 In stage 1 Inactive Centerline

Geotechnical Evaluation Download Download Brasil (Only portuguese)
Technical Report on Water Quality and Dust Download Download Brasil (Only portuguese)
Emergency Action Plan Download Download Brasil (Only portuguese)

Córrego da Lavagem Dam
Structure Purpose Structure type Operation Startup Embankment Raising Method Number of Embankment Raises Operational Status Construction Method
Córrego da Lavagem Dam Industrial tailings Dam 2002 In stage 1 Inactive Centerline

Geotechnical Evaluation Download Download Brasil (Only portuguese)
Technical Report on Water Quality and Dust Download Download Brasil (Only portuguese)
Emergency Action Plan Download Download Brasil (Only portuguese)

Murici Tailings Deposit - Central Module
Structure Purpose Structure type Operation Startup Embankment Raising Method Number of Embankment Raises Operational Status Construction Method
Murici Tailings Deposit - Central Module Industrial tailings Dam 2011 In stage 0 Active Single Stage

Geotechnical Evaluation Download Download Brasil (Only portuguese)
Technical Report on Water Quality and Dust Download Download Brasil (Only portuguese)
Emergency Action Plan Download Download Brasil (Only portuguese)

Murici Tailings Deposit - East Module
Structure Purpose Structure type Operation Startup Embankment Raising Method Number of Embankment Raises Operational Status Construction Method
Murici Tailings Deposit - East Module Industrial tailings Dry Stacking 2011 Continuous 0 Inactive Dry Stacking

Geotechnical Evaluation Download Download Brasil (Only portuguese)
Technical Report on Water Quality and Dust Download Download Brasil (Only portuguese)
Emergency Action Plan Download Download Brasil (Only portuguese)

Murici Tailings Deposit - West Module I
Structure Purpose Structure type Operation Startup Embankment Raising Method Number of Embankment Raises Operational Status Construction Method
Murici Tailings Deposit - West Module I Industrial tailings Dam 2016 In stage 2 Active Downstream Raising

Geotechnical Evaluation Download Download Brasil (Only portuguese)
Technical Report on Water Quality and Dust Download Download Brasil (Only portuguese)
Emergency Action Plan Download Download Brasil (Only portuguese)

Murici Tailings Deposit - West Module II
Structure Purpose Structure type Operation Startup Embankment Raising Method Number of Embankment Raises Operational Status Construction Method
Murici Tailings Deposit - West Module II Industrial tailings Dry Stacking 2018 In stage 0 Active Dry Stacking

Geotechnical Evaluation Download Download Brasil (Only portuguese)
Technical Report on Water Quality and Dust Download Download Brasil (Only portuguese)
Emergency Action Plan Download Download Brasil (Only portuguese)

Garrote Stack
Structure Purpose Structure type Operation Startup Embankment Raising Method Number of Embankment Raises Operational Status Construction Method
Garrote Stack Mining tailings Dry Stacking 2019 Continuous NA Active Dry Stacking

Emergency Action Plan Download Download Brasil (Only portuguese)

Aroeira Dam
Structure Purpose Structure type Operation Startup Embankment Raising Method Number of Embankment Raises Operational Status Construction Method
Aroeira Dam Mining tailings Dam 2001 In stage 7 Active Downstream Raising

Geotechnical Evaluation Download Download Brasil (Only portuguese)
Technical Report on Water Quality and Dust Download Download Brasil (Only portuguese)
Emergency Action Plan Download Download Brasil (Only portuguese)

Module III
Structure Purpose Structure type Operation Startup Embankment Raising Method Number of Embankment Raises Operational Status Construction Method
Module III Sediments Dam 1984 In stage 0 Active Single Stage

Emergency Action Plan Download Download Brasil (Only portuguese)

Vaso Atacocha
Structure Purpose Structure type Operation Startup Embankment Raising Method Number of Embankment Raises Operational Status Construction Method
Vaso Atacocha Mining tailings Dam 2008 In stage 6 Active Downstream
Ticlacayan
Structure Purpose Structure type Operation Startup Embankment Raising Method Number of Embankment Raises Operational Status Construction Method
Ticlacayan Mining tailings Dam 2001 In stage 5 Inactive Upstream Raising
Chicrin
Structure Purpose Structure type Operation Startup Embankment Raising Method Number of Embankment Raises Operational Status Construction Method
Chicrin Mining tailings Dam 2001 In stage - Inactive Upstream Raising
Malauchaca
Structure Purpose Structure type Operation Startup Embankment Raising Method Number of Embankment Raises Operational Status Construction Method
Malauchaca Mining tailings Dam 2006 In stage - Inactive Upstream Raising
Cajamarquilla
Structure Purpose Structure type Operation Startup Embankment Raising Method Number of Embankment Raises Operational Status Construction Method
Cajamarquilla Mining tailings Dam 2005 In stage - Inactive No Raising
Poza 1
Structure Purpose Structure type Operation Startup Embankment Raising Method Number of Embankment Raises Operational Status Construction Method
Poza 1 Industrial waste Dam 1980 In stage 3 Inactive Downstream
Poza 2
Structure Purpose Structure type Operation Startup Embankment Raising Method Number of Embankment Raises Operational Status Construction Method
Poza 2 Industrial waste Dam 1988 In stage 2 Inactive No Raising
Poza 3
Structure Purpose Structure type Operation Startup Embankment Raising Method Number of Embankment Raises Operational Status Construction Method
Poza 3 Industrial waste Dam 1993 In stage 0 Inactive No Raising
Poza 4
Structure Purpose Structure type Operation Startup Embankment Raising Method Number of Embankment Raises Operational Status Construction Method
Poza 4 Industrial waste Dam 1996 In stage 0 Inactive No Raising
Poza 5
Structure Purpose Structure type Operation Startup Embankment Raising Method Number of Embankment Raises Operational Status Construction Method
Poza 5 Industrial waste Dam 2011 In stage 2 Active Downstream Raising
Poza 6
Structure Purpose Structure type Operation Startup Embankment Raising Method Number of Embankment Raises Operational Status Construction Method
Poza 6 Industrial waste Dam 2014 In stage 1 Active No Raising
Poza Lodos Neutros
Structure Purpose Structure type Operation Startup Embankment Raising Method Number of Embankment Raises Operational Status Construction Method
Poza Lodos Neutros Industrial waste Dam 2009 In stage 4 Active Downstream
Presa Pahuaypite I
Structure Purpose Structure type Operation Startup Embankment Raising Method Number of Embankment Raises Operational Status Construction Method
Presa Pahuaypite I Sediments Dam 2007 In stage 0 Active No Raising
Presa Pahuaypite II
Structure Purpose Structure type Operation Startup Embankment Raising Method Number of Embankment Raises Operational Status Construction Method
Presa Pahuaypite II Sediments Dam 2012 In stage 0 Active No Raising
Pahuaypite I
Structure Purpose Structure type Operation Startup Embankment Raising Method Number of Embankment Raises Operational Status Construction Method
Pahuaypite I Mining tailings Dry Stacking 2007 Continuous NA Active Dry Stacking
Pahuaypite II
Structure Purpose Structure type Operation Startup Embankment Raising Method Number of Embankment Raises Operational Status Construction Method
Pahuaypite II Mining tailings Dry Stacking 2012 Continuous NA Active Dry Stacking
Deposito de Relaves Campanayoc
Structure Purpose Structure type Operation Startup Embankment Raising Method Number of Embankment Raises Operational Status Construction Method
Deposito de Relaves Campanayoc Mining tailings Dam 1980 Continuous 0 Inactive No Raising
Relavera Antigua 2
Structure Purpose Structure type Operation Startup Embankment Raising Method Number of Embankment Raises Operational Status Construction Method
Relavera Antigua 2 Mining tailings Dam 1980 Continuous 0 Inactive No Raising
Relavera Antigua 3
Structure Purpose Structure type Operation Startup Embankment Raising Method Number of Embankment Raises Operational Status Construction Method
Relavera Antigua 3 Mining tailings Dam 1980 Continuous 0 Inactive No Raising
Relavera Antigua 4
Structure Purpose Structure type Operation Startup Embankment Raising Method Number of Embankment Raises Operational Status Construction Method
Relavera Antigua 4 Mining tailings Dam 1980 Continuous 0 Inactive No Raising
Relavera Antigua 5
Structure Purpose Structure type Operation Startup Embankment Raising Method Number of Embankment Raises Operational Status Construction Method
Relavera Antigua 5 Mining tailings Dam 1980 Continuous 0 Inactive No Raising
El Porvenir
Structure Purpose Structure type Operation Startup Embankment Raising Method Number of Embankment Raises Operational Status Construction Method
El Porvenir Mining tailings Dam 1980 In stage 13 Active Centerline
Sinaycocha I
Structure Purpose Structure type Operation Startup Embankment Raising Method Number of Embankment Raises Operational Status Construction Method
Sinaycocha I Mining tailings Dam 2004 In stage 2 Inactive Upstream Raising
Sinaycocha II
Structure Purpose Structure type Operation Startup Embankment Raising Method Number of Embankment Raises Operational Status Construction Method
Sinaycocha II Mining tailings Dam 2004 In stage 0 Inactive No Raising

Tailings, Residue, Water and Waste Rock Management System

In order to control and monitor dams and tailings deposits, we apply guidelines from the International Commission on Large Dams and the Canadian Dam Association (CDA). We use processes and procedures that form the Integrated Dam Management System (called SIGBar) and an Integrated Deposit Management System (called SIGDep), permanently monitored by an independent firm, Geoconsultoria, which receives inspection data every 15 and 30 days, respectively, to issue its reports. This Management system is designed based on the routine monitoring of the structures and the monthly issuance of a “traffic light” that is taken to all hierarchical levels in the company, and presented at periodic meetings of the executive board.

Dam Management

nexa