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At June 2025
Coordinates: Lat -19.984809°, Long -43.472180°
Guidance Note
Refer to our guidance note.
Description and Lifecycle Design
The CDS II TSF is located in the state of Minas Gerais, in the municipality of Santa Bárbara, about 110 km from Belo Horizonte. The TSF is a conventional valley impoundment with a main embankment to the south of the TSF and a saddle wall east of the former decant pump platform. The CDS II TSF was built using the Centreline construction method, totalling nine raisings, the last of which took place in 2018, with a final height of 84m (elevation 816 mamsl) and a crest length of 538m.
The main embankment is made of a homogeneous compacted fill, with an internal drainage system composed of a chimney filter and horizontal blanket drain. A reinforcement buttress using filtered tailings and waste rock has been constructed at the toe of the facility to an elevation of 807mamsl. The spillway is located on the left abutment at an elevation of 814.33 mamsl.
In 2015, a saddle wall was constructed to seal the topographic contour of the TSF during the final wall raise. It is 13m high, 170m long, with a crest width of 4m. The saddle wall embankment was constructed using compacted soil, and the internal drainage comprises of a vertical filter and a horizontal blanket drain, a HDPE liner covers the inside slope of the embankment.
Chronology of TSF raises:
- 1984: Initial Embankment
- 1990: 1st Raise – Elevation 787.90 mamsl
- 1993: 2nd Raise – Elevation 792.90 mamsl
- 1994: 3rd Raise – Elevation 800.00 mamsl
- 2002: Downstream Buttress
- 2003: 4th Raise – Elevation 803.50 mamsl
- 2004: 5th Raise – Elevation 806.60 mamsl
- 2005: 6th Raise – Elevation 808.00 mamsl
- 2009: 7th Raise – Elevation 812.00 mamsl
- 2009: 8th Raise – Elevation 816.00 mamsl
- 2010: Saddle Wall – Elevation 816.00 mamsl
- 2022: Downstream Buttress (Filtered Tailings and Waste Rock) – Decharacterisation
The de-characterisation plan for the CDS II TSF consists of:
- Phase I: Constructing a buttress downstream of the TSF using compacted filtered tailings and waste rock – concluded in 2023.
- Phase II: Installation of the final cover system over the reservoir area – in progress.
CDS II TSF General Information
| Facility Name | CDS II TSF |
| Start of Operation | 1984 |
| Operational Construction Method | Centre Line |
| Current Deposition Method | Decharacterisation of the TSF in progress |
| Target Annual Deposition Rate | Decharacterisation of the TSF in progress |
| Current Tailings Volume | 9.4Mm3 |
| Design/License Capacity – Volume/Tonnage | 9.4Mm3 |
| Crest Elevation | Main Embankment – 816mamsl Closing Dyke – 816mamsl |
| Spillway Elevation | 814.33mamsl |
| Maximum Height | Main Embankment – 84m Closing Dyke – 13m |
| Outer Wall Profile | 1V: 2.0H (Main Embankment) 1V: 2.0H (Closing Dyke) |
Consequence Classification
| GISTM Classification | Extreme |
Risk Assessment
AngloGold Ashanti’s comprehensive risk management system uses designs and controls to eliminate risks and where there are remaining risks, these are mitigated such that the residual risk is a As Low As Reasonably Practicable (ALARP).
Risk assessments are conducted by a multi-disciplinary team in collaboration with the Engineer of Record (EoR) for each facility in line with nationally or internationally accepted best practices. The risk assessment report provides a summary of the key details of the structure, including site investigations, geotechnical parameters, foundation conditions, embankment properties, drainage system details, spillway details, monitoring criteria, and the tailings disposal plan. It also details the risk-analyses methodology (using the qualitative bowtie method), potential failure modes along with their susceptibility and consequences, and the control and mitigation measures.
In the risk analysis conducted in 2024, nine risks were mapped that could in theory lead to a reduction in the dam’s structural performance, and all risks were classified as acceptable. Actions were recommended for these risks and general recommendations to be applied in the operation and maintenance of the TSF. All these action plans aim to reduce the probability of possible risks, as well as minimise possible impacts resulting from occurrences in the structure. Focusing on the final phase of implementation of the Detailed Decharacterisation Project, eight risks were identified, two of which fall within the ALARP range.
Impact Assessment
The impact of a potential flow failure has been assessed considering the impact to human health and life, the environment, social and cultural impacts, as well as the infrastructure and economic impacts. These potential impacts have been used to inform the TSF Classification and the risk assessment consequence definition and the mitigation measures to be implemented.
For the CDS II TSF the Self-rescue Zone was mapped out for 10km as this was greater than the time for the inundation wave to cover the distance in 30 minutes as required by the Brazilian legislation.
The municipalities and areas affected by the impact zone and the main social information of the potential floodplain in the event of a rupture of the CDS II TSF is shown in the tables below.
Areas affected by Impact Zone
CDS II TSF
| Municipalities in ZAS | Santa Bárbara & Catas Altas & Barões de Cocais |
| Municipalities in ZSS | Santa Bárbara & Barões de Cocais |
| Main Watercourses Impacted | Rio Conceição, Ribeirão Caraça & Rio Santa Bárbara |
| Watersheds | Rio Doce |
| Areas with Potential for Interference | Private properties; UHE Peti (owned by CEMIG); road infrastructure (MG-262 and MG-129) and Caraça road (in all scenarios), streets and bridges; commercial and religious establishments |
Summary of the socio-territorial characterisation of the impact zone
| Type of Property | Quantity |
|---|---|
| Registered properties | 712 |
| Residences | 567 |
| Building | 73 |
| Economic activity | 45 |
| Entities and public agencies | 27 |
| Total Population in ZAS | 2,465 |
| Population with mobility difficulties and/or special needs | 835 |
| Population with Special Needs | 145 |
| Number of Sensitive buildings in ZAS | 69 |
Performance Reviews
AngloGold Ashanti has a comprehensive Tailings Review System which incorporates reviews from multiple levels and internal and external parties. All AngloGold Ashanti TSFs are subject to the following reviews:
- RTFE Performance Reviews – monthly inspections
- EoR Inspections – Monthly, with two safety declarations submitted to the Brazilian National Mining Agency (ANM) in March and September of each year.
- Independent Review of the Emergency Response and Preparedness Plan (EPRP) – Annually
- ITRB Review – Annually
- AngloGold Ashanti Corporate Review – Annually
- Dam Safety Review (RPSB) – Typically every three years or when change TSF
| Reviews | Most Recent Review | Next Planned Review |
|---|---|---|
| EoR | March 2025 | Monthly – 2025 |
| ITRB | May 2025 | May 2026 |
| RPSB | Jan 2025 | October 2026 |
AngloGold Ashanti has adopted the following ranking system for independent reviews:
Priority 1 – A dam safety issue considered immediately dangerous to life, health or the environment, or presents a significant risk of regulatory enforcement. Requires immediate action and to be completed as soon as practically possible but certainly within 2 months
Priority 2 – If not corrected, a concern that could result in a dam safety issue leading to injury, health impact or discontinuity of operations. Requires immediate planning and completion by a date and specified by operations but as a minimum within 5-6 months
Priority 3 – Single occurrence of deficiency or non-conformance that alone would not be expected to result in dam safety issues, discontinuity of operations or regulatory intervention. Requires that measures be taken no later than a date that would prevent escalation, but no later than one year
Priority 4 – A recommendation based on good practice, improvement, or risk reduction. Recommendation towards best practices and mitigating risk associated.
No Priority 1 recommendations have been issued by the ITRB for the CDS II TSF.
Environmental and Social
Environment and Social monitoring programmes form part of AngloGold Ashanti’s Health, Safety, Environment (ISO14001) and Social Communities (HSEC) management systems, which act to fulfil the environmental social management system requirements under the GISTM. These environment and social monitoring programmes are comprehensively reviewed, and mitigation measures implemented as and where required. Further information on of our environment and social monitoring programmes, and performance results can be found in AngloGold Ashanti’s Sustainability Reports.
An easily accessible and effective grievance mechanism has been implemented so that any formal complaints can be submitted by stakeholders and resolved.
Emergency Response and Preparedness
Emergency preparedness and response planning (EPRP) relies on an emergency notification system that consists of remote stations equipped with sirens that are linked to the control room at the Queiroz plant, which scans tiltmeters located on the dam face. Manual activation of the sirens is available locally as redundancy.
The latest dam breach study was conducted in December 2023 and an EPRP training exercise, involving the community, was documented as having been undertaken in March 2025. Training exercises have included military civil organisations (police and fire) for various communities.
The escape routes and meeting points are sign posted. These were developed based on the zone of influence, in which a maximum walking distance of 1,000m was considered to allow a quick and safe route to meeting points. The meeting point signage has information such as telephone numbers of emergency agencies, safety recommendations for the population, among other self-preservation information.
A copy of the CDS II EPRP can be downloaded on the following link: BARRAGEM CDS II – AngloGold Ashanti Brasil
Financial Capacity
AngloGold Ashanti confirms it has adequate financial capacity to cover the agreed share of estimated costs of planned closure, early closure, reclamation, and post-closure monitoring and maintenance of the CDS II TSF and its appurtenant structures.
Guidance Note
Certain statements contained in this document, other than statements of historical fact, including, without limitation, those concerning the economic outlook for the gold mining industry, expectations regarding gold prices, production, total cash costs, all-in sustaining costs, cost savings and other operating results, return on equity, productivity improvements, growth prospects and outlook of AngloGold Ashanti’s operations, individually or in the aggregate, including the achievement of project milestones, commencement and completion of commercial operations of certain of AngloGold Ashanti’s exploration and production projects and the completion of acquisitions, dispositions or joint venture transactions, AngloGold Ashanti’s liquidity and capital resources and capital expenditures, the consequences of the COVID-19 pandemic and the outcome and consequences of any potential or pending litigation or regulatory proceedings or environmental, health and safety issues, are forward-looking statements regarding AngloGold Ashanti’s financial reports, operations, economic performance and financial condition.
These forward-looking statements or forecasts are not based on historical facts, but rather reflect our current beliefs and expectations concerning future events and generally may be identified by the use of forward-looking words, phrases and expressions such as “believe”, “expect”, “aim”, “anticipate”, “intend”, “foresee”, “forecast”, “predict”, “project”, “estimate”, “likely”, “may”, “might”, “could”, “should”, “would”, “seek”, “plan”, “scheduled”, “possible”, “continue”, “potential”, “outlook”, “target” or other similar words, phrases, and expressions; provided that the absence thereof does not mean that a statement is not forward-looking. Similarly, statements that describe our objectives, plans or goals are or may be forward-looking statements.
These forward-looking statements or forecasts involve known and unknown risks, uncertainties and other factors that may cause AngloGold Ashanti’s actual results, performance, actions or achievements to differ materially from the anticipated results, performance, actions or achievements expressed or implied in these forward-looking statements. Although AngloGold Ashanti believes that the expectations reflected in such forward-looking statements and forecasts are reasonable, no assurance can be given that such expectations will prove to have been correct.
Accordingly, results, performance, actions or achievements could differ materially from those set out in the forward-looking statements as a result of, among other factors, changes in economic, social, political and market conditions, including related to inflation or international conflicts, the success of business and operating initiatives, changes in the regulatory environment and other government actions, including environmental approvals, fluctuations in gold prices and exchange rates, the outcome of pending or future litigation proceedings, any supply chain disruptions, any public health crises, pandemics or epidemics (including the COVID-19 pandemic), the failure to maintain effective internal control over financial reporting or effective disclosure controls and procedures, the inability to remediate one or more material weaknesses, or the discovery of additional material weaknesses, in the Company’s internal control over financial reporting, and other business and operational risks and challenges and other factors, including mining accidents.
For a discussion of such risk factors, refer to AngloGold Ashanti’s annual report on Form 20-F for the financial year ended 31 December 2024 filed with the United States Securities and Exchange Commission (SEC). These factors are not necessarily all of the important factors that could cause AngloGold Ashanti’s actual results, performance, actions or achievements to differ materially from those expressed in any forward-looking statements. Other unknown or unpredictable factors could also have material adverse effects on AngloGold Ashanti’s future results, performance, actions or achievements. Consequently, readers are cautioned not to place undue reliance on forward-looking statements.
AngloGold Ashanti undertakes no obligation to update publicly or release any revisions to these forward-looking statements to reflect events or circumstances after the date hereof or to reflect the occurrence of unanticipated events, except to the extent required by applicable law. All subsequent written or oral forward-looking statements attributable to AngloGold Ashanti or any person acting on its behalf are qualified by the cautionary statements herein.