Greenfields TSF, Ghana

At 10 April 2024

Drone image of Greenfields TSF
*Coordinates: Lat. 5.233688°, Long. -2.066815°*

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 for implementation 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 or stream.

AngloGold Ashanti has an internal corporate tailings management team including an Accountable Executive. AnGold 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, and an additional geotechnical investigation is to be conducted to provide further certainty regarding foundation characteristics.

An updated stability assessment will incorporate additional 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. These impacts will be confirmed by the detailed assessments and EPRP development.

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:

EoR Inspections – Typically quarterly and Annual Performance Reviews
ITRB Review – Annually
AngloGold Ashanti Corporate Review – Annually
Independent 3^rd Party Regulatory Review – Quarterly
Dam Safety Review (DSR) – Typically every five years

Reviews	Most Recent Review	Next Planned Review
EoR	Dec 2023	Q1 2024
ITRB	July 2023	Q3 2024
Regulatory	March 2024	Q2 2024
DSR	NA	2026

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 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.

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.

No material findings have been made in relation to the environmental and social monitoring programme, in relation to the TSF in 2023.

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 developed an emergency management plan which 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 emergency preparedness and response planning specific to modelled potential failure scenarios of the GTSF is under way and we are targeting end 2025 to have these formally developed.

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

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.

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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.