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Dams and Waste

Sustainability: priority in our way of operating

Sustainability has been a strategic topic since the establishment of Nexa and has always guided our business in all aspects. This means special attention to the management of waste and tailings resulting from the activities and their constant improvement to increasingly mitigate and reduce our socio-environmental impacts.

We invest in the development of new technologies aimed at the reuse of tailings and waste and we have three different ways of disposing them: return to the mine (backfill), dry stacking and, finally, we dispose of the materials in dams.

Currently, only 31.8% of the tailings and waste generated by us in Brazil and Peru are disposed of in dams.

In line with the transparency principles and aiming to maintain effective communication with our stakeholders,, we have a specific page on Dams and Deposits.

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Actual Impact

Dam and waste management is conducted with a focus on operational and socio-environmental integrity, taking into account the complexity of monitoring, storage, and applicable regulatory requirements. Strict controls are implemented to prevent environmental impacts and mitigate legal and reputational risks. At the same time, the expansion of circular economy initiatives strengthens the use of waste as inputs for other sectors, generating efficiency and business opportunities.

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Waste generated, diverted, and directed to disposal
Correlated indicators
GRI Dimension:
Environmental
GRI Code:
306-3, 306-4 e 306-5
SASB Sector:
Mining and Metals
SASB Dimension:
Waste and Hazardous Materials Management
SASB Code:
EM-MM-150 a.1
SASB Code:
EM-MM-150 a.2
SDG
Total Weight of Waste, by type and disposal method (tons)
2023 2024 2025*
Within organization Non-hazardous Diverted from disposal
Composting 1.124,11 1.069,29 859,82
Reuse 429,83 119,41 1,17
Recycling 5576,069 6145,352 6.863,91
Recovery 0 0 0
Other 0 0 0
Directed to disposal
Incineration (or use as fuel) 0 0 0
Sanitary landfill 606,9 385,92 0
Co-processing/refining 0 0 0
On-site storage 0 0 0
Underground waste injection 0 0 0
Industrial landfill 90 132 1.944
Other 329,8 270,43 669,44
Total non-hazardous waste 8.156,70 8.122,40 10.338,34
Hazardous Diverted from disposal
Composting 0 0 0
Reuse 646,65 565,23 0,17
Recycling 0 0 503,88
Recovery 0 0 0
Other 0 0 215,45
Directed to disposal
Incineration (or use as fuel) 0 0 0
Sanitary landfill 226,35 124,55 0
Co-processing/refining 0 0 0
On-site storage 0 0 3011,76
Underground waste injection 0 0 0
Industrial landfill 2028,92 2063,11 870
Other 0 0 0
Total hazardous waste 2.901,92 2.752,89 4.601,26
Outside Organization Non-hazardous Diverted from disposal
Composting 54,96 151,862 77,34
Reuse 915,33 168,57 0
Recycling 3.758,96 6.261,02 8.030,64
Recovery 883 980,32 0
Other 411,16 0 73,28
Directed to disposal
Incineration (or use as fuel) 6,08 112,08 0
Sanitary landfill 1.511,42 1.252,90 1.201,46
Co-processing/refining 605,63 1135,67 1.366,67
On-site storage 36,14 6,2 0
Underground waste injection 0 0 0
Industrial landfill 132,9 441,55 1571,95
Other 248,27 817,635 11150,045
Total non-hazardous waste 8.563,84 11.327,81 23.471,38
Hazardous Diverted from disposal
Composting 0 0 0
Reuse 2.933,55 7.196,92 55,41
Recycling 0 0 5.044,38
Recovery 0 0 0
Other 0 136,09
Directed to disposal
Incineration (or use as fuel) 1,19941 0,59375 0,32
Sanitary landfill 0 0 0
Co-processing/refining 2.929,44 2.869,83 2.114,35
On-site storage 0 0 34,64
Underground waste injection 0 0 48,5
Industrial landfill 3063,63 3329,8 3.239,80
Other 838,465 796,47 2.640,82
Total hazardous waste 9.885,11 14.193,61 13.314,31
Total Geral de Resíduos 29.507,58 36.396,71 51.725,28
Percentage of waste reused, composted, recycled, or recovered 57% 62% 42%
 
(*) The difference between waste generated and waste disposed of or recycled is due to the disposal or recycling of waste from inventory accumulated in previous years. In addition, the Três Marias unit receives material from external organizations for internal recycling. In prior years, we reported only the amount disposed of, without distinguishing between waste generated and disposed of. Therefore, starting in 2025, this difference is presented.
Total amounts of overburden, rock, tailings and sludges and their associated risks
Correlated indicators
GRI Dimension:
Environmental
GRI Code:
306-3
SASB Sector:
Mining and Metals
SASB Dimension:
Waste and Hazardous Materials Management
SASB Code:
EM-MM-150 a.4, EM-MM-150 a.5, EM-MM-150 a.6, EM-MM-150 a.7, EM-MM-150 a.8
Volume of Waste (thousand tons) and Recycled Percentage
2023 2024 2025
Hazardous Total mining and smelting waste Tailings 10.817.946,78 11.735.962,14 11.388.167,28
Waste rock 10.609.180,23 10.690.799,83 8.993.856,00
Tailings recycled, reused or remanufactured 2.932.181,95 2.938.860,02 3.136.941,15
Waste rock recycled, reused or remanufactured 694.255,00 1.150.310,00 312.844,04
Total non-mining and smelting waste 14.381,49 16.946,50 15.242,05
Non-hazardous
 Total mining and smelting waste Tailings 1.317.727,79 1.207.235,00 1.423.678,29
Waste rock 988.457,70 886.194,00 886.174,00
Tailings recycled, reused or remanufactured 358,00 (36%) - -
Waste rock recycled, reused or remanufactured 90.967,00 201.113,00 -
Total non-mining and smelting waste 11.144,48 19.450,21 18.699,85
 
Mine sites where acid rock drainage is predicted to occur actively mitigated, and under treatment or remediation
Correlated indicators
SASB Sector:
Mining and Metals
SASB Dimension:
Impacts on biodiversity
SASB Code:
EM-MM-160a.2
SDG
  2023 2024 2025
Status of Acid Rock Drainage at Mine Sites (*) Percentage of annual mining production in metric tons from locations where acid rock drainage is "EXPECTED TO OCCUR". 7% 10% 40%
Percentage of annual mining production in metric tons from mining locations where acid rock drainage is "ACTIVELY MITIGATED". 6% 0% 100%

Percentage of annual mining production in metric tons from mining locations where acid rock drainage is "UNDER TREATMENT OR REMEDIATION".

 2% 0 0
 

You can find all the information about dam management on this link.

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Dam Management Integrated System (SIGBar)

Composed of rules and measures of regular monitoring actions, from which we control all structures, SIGBar establishes guidelines for the management of documents, monitoring, evaluation, risk analysis, compliance with standards and legislation, training personnel, operation of structures and other arrangements.

Risks

  • Breaches or instability with socio-environmental impacts
  • Regulatory restrictions and operational shutdowns due to storage limits
  • Failures or non-compliance may result in fines and production interruptions

Opportunities

  • Expansion of circular economy initiatives

Dam Management

Our dam management routine takes place on an ongoing basis by an independent firm, which receives data from inspections performed every fifteen days and consolidates data from all monitoring activity to issue monthly stability reports. 

Daily
  • Comply with operational procedures

 

  • Conduct operational inspections

 

  • Perform monitoring

 

Monthly
  • Sending data to ‘Geoconsultoria’ for stability assessment

 

  • Perform monitoring

 

  • Issue the SIGBAR indicator

 

  • Consolidation of monthly reports and issuance of indicators.
Every 15 Days
  • Conduct on-site inspections of safety conditions

 

  • Perform monitoring

 

  • Sending data to ‘Geoconsultoria’ for evaluation.

Our Geotechnical Assessments, Reports and Action Plans related to dams

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Communication channel

The Ethics Line, an impartial and transparent communication channel, guarantees the confidentiality of information and preserves the identity of involved persons. Through this, it is possible to clarify doubts, forward non-compliances complaints of dam golden rules, and monitor submitted complaints.

The submission of a complaint (anonymous or not) can be made through the website or the numbers below.

Compliance Line

Brazil

0800 892 0741

Canada

1 855 888 9926 / 1 885 350 9393

Luxembourg

800 201 11

Peru

0800 50 0000 / 0800 50 288

United States

1 855 8889926

Austria

0800 200 288

Our aspiration

Our aspiration is to be recognized in the communities where we operate as an engaged and transparent company in dam safety and management, following international standards and being active in the regions where we operate.

Our contribution to the SDGs

SDGs related to the topic:

 

In 2017, we committed to the global agenda comprising 17 goals and 169 targets to be achieved by 2030.

SDGs related to the topic

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Learn more about Nexa at the links below

Strategy

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Climate Change

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Natural Capital

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