Tropicana TSF, Australia
At 10 April 2024

Coordinates: Lat. -29.232246°, Long. 124.552217°
Guidance Note
Refer to our guidance note.
Description and Lifecycle Design
The TSF is a ‘paddock’ style facility with a single rectangular cell and was commissioned in 2012. Tailings are deposited sub-aerially from perimeter spigots to form a beach sloping towards the decant pond. The TSF has a compacted clay liner with a secondary HDPE liner in the area below and adjacent to the decant pond. Water is recovered and returned to the processing plant by a pumped decant pond recovery system utilising floating turrets and an underdrainage recovery system as the base of the TSF. The TSF is raised in stages over the mine life employing downstream construction techniques as part of an Integrated Waste Landform incorporating adjacent waste rock landforms.
The Tropicana mining fleet place fresh competent waste rock directly from the mining pits as the embankment structural fill and bulk fill. The low permeability material zone on the internal face of the structural embankment is constructed with compacted locally sourced clay material by an external earthmoving contractor.
The TSF has a current maximum height of 38m and a maximum design height of 44m. The waste rock embankments are constructed with a base width of approximately 270 m and a crest width of 60m (inclusive of Zone A). At closure, the downstream slope will be dozed down to 15 degrees and a crest width of 10m will be retained. The TSF surface will be covered, and the surface and side slopes will be rehabilitated in line with the designated post closure land use as outlined in the TGM Mine Closure Plan.
AngloGold Ashanti has an internal corporate tailings management team including an accountable executive. AGA 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.
Tropicana TSF General Information
Start of Operation | 2013 |
Construction Method | Downstream waste rock wall with internal clay zone |
Current Deposition Method | Spigot Deposition |
Target Annual Production Rate | 9.5Mtpa |
Current Tailings Volume/Tonnage | 46.6Mm3 / 71.8 Mt |
Crest Elevation | 372 Mamsl |
Spillway Elevation | 371 Mamsl |
Maximum Height | 38m |
Outer Wall Profile | 1V:2H |
Consequence Classification
GISTM Consequence Classification | Very High |
Risk Assessment
Risk assessments are conducted with a multidisciplinary 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 were undertaken for the TSF. As demonstrated through the PFMA, the TSF has eliminated most potential failure modes through its robust design. Remaining 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 ALARP.
The assessment identified the risks of:
- Embankment foundation failure under static loading
- TSF foundation failure in areas founded on unknown material
- Foundation failure under seismic loading as material
Existing controls include:
- Stability analysis conducted demonstrating adequate Factor of Safety based on reasonable range of material parameters
- Monitoring instrumentation implemented to monitor phreatic surface
- Regular TSF inspections by shift operators inclusive of embankment toe/foundation
- Conservative material parameters used to account for variability
- Laboratory testing (QC) of construction materials
- Operational decant and underdrainage systems
- HDPE lined area beneath operational pond
- TSF Operating Manual defines the Triggered Action Response Plan for water levels in piezometers
Additional geotechnical investigation is to be conducted to provide additional certainty to foundation characteristics.
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 also the risk assessment consequence definition and the mitigation measures to be implemented.
Modelling of a potential failure indicates that a failure of the south-west wall could impact the processing plant area and associated mine infrastructure.
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 – typically quarterly
- EoR Inspections – typically quarterly and Annual Performance Reviews
- ITRB Review – Annually
- AGA Corporate Review – Annually
- Independent 3rd Party Regulatory Review – Annually
- Dam Safety Review – Typically every five years
Reviews | Most Recent Review | Next Planned Review |
---|---|---|
EoR | Dec 2023 | Q4 2024 |
ITRB | Sep 2023 | Q4 2024 |
Regulatory | Sep 2023 | Q4 2024 |
DSR | NA | Q3 2024 |
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 at 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 to date for the TGM 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 fulfill 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.
No material findings were made in relation to the TSF in 2023.
Seepage from the TSF is being monitored and managed below specified trigger levels.
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
The Tropicana Gold Mine has no external parties or population within the region or flow path of a hypothetical tailings breach. The mine has a dedicated Emergency Response Team and Emergency Management Plan (EMP). The EMP 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. Due to the remote location of the Tropicana site, the site emergency response team plan all initial responses without additional support from external or public agencies.
The TSF’s emergency preparedness and response planning is a dedicated plan that is to be appended to the site wide EMP 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 and primary responders.
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 TSF and its appurtenant structures. The Tropicana Gold Mine is 70% owned by AngloGold Ashanti. Joint Venture partners are responsible for their agreed share of closure and rehabilitation costs.
Guidance Note
This document provides the information required under Requirement 15.1.B of the GISTM.
This document should be read in conjunction with the information relating to AngloGold Ashanti’s tailings management practices that is available on the AngloGold Ashanti website, as well as the risk factors and other disclosures in AngloGold Ashanti’s annual report on Form 20-F for the year ended 31 December 2023 to be filed with the United States Securities and Exchange Commission (SEC) (the “Form 20-F”).
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, all-in 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 limited to 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 AngloGold Ashanti’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 “Item 3D: Risk Factors” and elsewhere in the Form 20-F. 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 of this document 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.