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At June 2025
Coordinates: Lat. 5.233688°, Long. -2.066815°
Guidance Note
Refer to our guidance note.
Description and Lifecycle Design
The Greenfields TSF (GTSF) is located at the Iduapriem mine in Ghana and was commissioned in 2011, decommissioned in 2023 and is now in the process of closure. The facility was constructed with saprolite starter walls and an HDPE liner in the basin footprint. Collector drains were constructed above and below the HDPE liner to collect process water and seepage water respectively. The TSF was raised with saprolite/phyllite embankment raises using the upstream method. The walls were later buttressed with coarse competent rock fill. Tailings was deposited via spigots into the basin and decant water is recovered by a shallow intake pump system. Two penstocks were raised concurrently with the TSF to serve as the emergency spillway for the facility. The TSF has a maximum height of 49m.
The detailed closure design is in progress. For closure the downstream slope will be further buttressed and flattened by additional rock-fill in specific areas. The TSF surface and side slopes will be covered and rehabilitated in line with the designated post-closure land use of secondary forest with the potential for cash cropping on the basin, as outlined in the Mine Closure Plan. Surface water run-off from the rehabilitated surface will flow off the surface via a dedicated channel.
AngloGold Ashanti has an internal corporate tailings management team including an Accountable Executive. AngloGold Ashanti has appointed an internal Responsible Tailings Facility Engineer (RTFE) an external Engineer of Record (EoR) and an Independent Tailings Review Board (ITRB) at this facility to oversee and govern the design, construction, operations, maintenance, and surveillance of the facility.
GTSF General Information
| Period of Operation | 2011-2023 |
| Construction Method | Upstream with saprolite borrow material for embankment raises. Rock-fill buttressing. |
| Deposition Method | Single cell, rotational sub-aerial spigot deposition |
| Target Annual Production Rate | Decommissioned |
| Current Tailings Volume / Tonnage | 46.6Mm3 / 71.8Mt |
| Crest Elevation | 87m RL |
| Spillway Elevation | 85.3m RL |
| Maximum Height | 49m |
| Outer Wall Profile | 1V:5H overall |
Consequence Classification
| GISTM Consequence Classification | Very High |
Risk Assessment
Risk assessments are conducted by a multi-disciplinary team and in collaboration with the EoR for each facility. The risk assessments, including the additional mitigation measures and residual risks, are reviewed by the ITRB and are to be approved by the Accountable Executive.
A Potential Failure Modes Assessment (PFMA) and a Failure Modes Effects Assessment (FMEA) were undertaken for the TSF as part of the closure design process. Potential failure modes were carried through to the FMEA to quantify the current and residual risk and identify additional mitigation measures or controls to further reduce the risks to a As Low As Reasonably Practicable (ALARP).
The assessment identified the risks of:
- Flow in receiving watercourse exceeding set parameters relative to pre-closure flows
- Global failure due to liquefaction
Existing controls include:
- Natural attenuation of secondary forest, flat slope angle of basin and existing natural stream with flood history.
- Buttressed embankments meeting the minimum residual conditions for stability criteria, on-going monitoring and performance review, further draw-down of phreatic surface post-decommissioning and implementation of closure cover.
Further hydrological studies of downstream catchment and additional active attenuation are to be considered in the detailed design. Geotechnical investigation has been conducted to provide further certainty regarding foundation characteristics.
An updated stability assessment will incorporate the geotechnical information from the detailed investigation, including the consideration of phreatic surface response over time.
Impact Assessment
The impact of a potential flow failure has been assessed, taking into consideration the impact to human health and life, the environment, infrastructure and the economy, as well as social and cultural consequences. These potential impacts have been used to inform the TSF Classification and the risk assessment consequence definition and the mitigation measures to be implemented.
Modelling of a potential failure indicates that the areas to north and south of the GTSF could be affected and could impact human settlements, farming, water resources and environmental resources.
Performance Reviews
AngloGold Ashanti has a comprehensive Tailings Review System which incorporates reviews from multiple levels and internal and external parties. The TSF is subject to the following reviews:
- RTFE Performance Reviews – typically quarterly
- EoR Inspections – Typically quarterly and Annual Performance Reviews
- ITRB Review – Annually
- AngloGold Ashanti Corporate Review – Annually
- Independent 3rd Party Regulatory Review – Quarterly
- Dam Safety Review (DSR) – Typically every five years
| Reviews | Most Recent Review | Next Planned Review |
|---|---|---|
| EoR | March 2025 | Q2 2025 |
| ITRB | July 2024 | Q3 2025 |
| DSR | NA | 2025 |
AngloGold Ashanti has adopted the following ranking system for independent reviews: Priority 1 actions are classified as a material finding.
Priority 1 – A dam safety issue considered immediately dangerous to life, health or the environment, or presents significant risk of regulatory enforcement.
Priority 2 – If not corrected, a concern that could result in a dam safety issue leading to injury, health impact or discontinuity of operations.
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.
Priority 4 – A recommendation based on good practice, improvement, or risk reduction.
No material findings (Priority 1) have been identified for the GTSF in the most recent reviews.
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.
There is potential for ground water seepage from TSFs and ground water conditions around all our TSFs are regularly monitored. Where groundwater impact plumes exist, their migration is modelled and managed, as necessary to avoid interaction(s) with potential receptors.
Environmental monitoring programme has shown improvements in supernatant water quality through dilution effect from rainfall following cessation of tailings deposition into the GTSF, and a significant reduction in dust generation from the TSF following grassing of the tailings beach in 2023.
No material findings have been made regarding social monitoring programme in relation to the TSF.
An easily accessible and effective grievance mechanism has been implemented and will continue to operate so that any formal complaints can be submitted by stakeholders and resolved.
Emergency Response and Preparedness
The mine has a dedicated Emergency Response Team and Emergency Management and Response Plan (EMRP). The EMRP identifies potential events and incidents, defines those personnel responsible for implementation of the response, and describes procedures for notification, communication and escalation of the emergency response.
The TSF emergency preparedness and response planning is a dedicated plan that is appended to the site wide EMRP and the facility operation, maintenance and surveillance manual. In the event of a tailings dam related emergency, the Emergency Response Team would be the first responders.
Financial Capacity
AngloGold Ashanti confirms it has adequate financial capacity to cover the estimated costs of planned closure, early closure, reclamation, and post-closure monitoring and maintenance of the GTSF 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.