Mineral Resource and Mineral Reserve – a summary
AngloGold Ashanti strives to actively create value by growing its major asset – the Mineral Resource and Mineral Reserve. This drive is based on active, well-defined brownfields and advanced project development programmes, innovation in both geological modelling and mine planning, and continual optimisation of the asset portfolio. Ensuring a viable Mineral Resource and Mineral Reserve pipeline enables delivery of sustained value-adding growth in the long term.
The Mineral Resource, as reported, is inclusive of the Mineral Reserve component, unless otherwise stated.
Responsible management of our Mineral Resource and Mineral Reserve, our exploration programme and related planning, is vital in optimising the operating lives of our assets. In so doing, AngloGold Ashanti ensures that it is able to deliver on its strategy and related strategic objectives, in particular, maintaining longterm optionality and improving the quality of our portfolio. See also Exploration and planning for the future in this report.
Reporting compliance
AngloGold Ashanti reports its Mineral Resource and Mineral Reserve in accordance with the minimum standards prescribed by the South African Code for the Reporting of Exploration Results, Mineral Resources and Mineral Reserves, 2016 edition (SAMREC Code) and Section 12.13 of the JSE Listings Requirements (as updated from time to time).
We achieve this by ensuring the principles of integrity, transparency and materiality are central to the compilation of this report and through using the reporting criteria and definitions as detailed in the SAMREC Code. The changes to AngloGold Ashanti’s Mineral Resource and Mineral Reserve were reviewed in compliance with the SAMREC Code, and it was concluded that detailed reporting as defined in Table 1 of the SAMREC Code for significant operations or projects will be provided for Geita and for the first-time Mineral Resource declaration for North Bullfrog. For the remaining assets, the Company will continue to provide the high-level of detail it has in previous years to comply with the transparency requirements of the SAMREC Code.
Price assumptions
The Mineral Resource and Mineral Reserve are based on the use of economic assumptions which provide a basis for establishing the reasonable prospects of economic extraction for the Mineral Resource, and for establishing the expected price for the Mineral Reserve. These economic assumptions, which include long-range commodity price, exchange rate forecasts, and management estimates using a range of techniques including historic price averages, are prepared in-house and reviewed annually. AngloGold Ashanti selects a conservative Mineral Reserve price relative to its peers. This is done to fit into its strategy of including a margin in the mine planning process. The resultant plan is then valued at a higher business planning price.
Gold price
The following gold prices were used as the basis for estimation, unless otherwise stated:
| Local prices of gold | |||||
|---|---|---|---|---|---|
| Gold price $/oz |
Australia AUD/oz |
Brazil BRL/oz |
Argentina ARS/oz |
Colombia COP/oz |
|
| Mineral Reserve | |||||
| 2022 | 1,400 | 1,919 | 7,830 | 208,000 | 4,261,380 |
| 2021 | 1,200 | 1,633 | 6,182 | 134,452 | 3,849,000 |
| Mineral Resource | |||||
| 2022 | 1,750 | 2,416 | 9,401 | 253,500 | 6,076,725 |
| 2021 | 1,500 | 2,072 | 7,940 | 173,065 | 5,336,250 |
Copper price
The following copper prices were used as the basis for estimation, unless otherwise stated:
| Local prices of copper |
||
|---|---|---|
| Copper price $/lb |
Colombia COP/lb |
|
| Mineral Reserve | ||
| 2022 | 2.90 | 9,302 |
| 2021 | 2.90 | 9,302 |
| Mineral Resource | ||
| 2022 | 3.50 | 12,451 |
| 2021 | 3.50 | 12,451 |
Mineral Resource
Gold
The AngloGold Ashanti gold Mineral Resource increased from 123.2Moz as at 31 December 2021 to 131.4Moz as at 31 December 2022. This annual net increase of 8.2Moz includes 5.1Moz in relation to the first-time reporting of the Mineral Resource for North Bullfrog and Mother Lode (after the acquisition of Corvus Gold in January 2022) as well as Sterling including the Crown Block (after the acquisition of Coeur Sterling in November 2022). Increases due to changes in economic assumptions of 2.7Moz and exploration and modelling changes of 7.1Moz, were partially offset by depletion of 3.2Moz and other factors of 3.5Moz. The Mineral Resource was estimated using a gold price of $1,750/oz, unless otherwise stated (2021: $1,500/oz).
Gold Mineral Resource — year-on-year changes
| Moz | ||
|---|---|---|
| Mineral Resource as at 31 December 2021 | 123.2 | |
| Acquisitions | North Bullfrog | 2.5 |
| Sterling | 0.9 | |
| Mother Lode | 1.7 | |
| Sub-total | 128.3 | |
| Depletions | (3.2) | |
| Sub-total | 125.1 | |
| Additions | Due to: | |
| Siguiri | Exploration success, minor model changes and the increase in the Mineral Resource price | 3.2 |
| Geita | Exploration success and changes in methodology due to revised estimation parameters, and refined ore wireframes as well as an increase in the Mineral Resource price and decrease in costs | 2.3 |
| Sunrise Dam | An increase in Mineral Resource price resulting in the newly optimised Cleo cutback, exploration drilling activities and model methodology changes | 1.1 |
| Silicon | Exploration success and a change in the Mineral Resource price | 0.8 |
| AGA Mineração | Exploration at Córrego do Sítio (CdS), Cuiabá and Lamego together with an increase in the Mineral Resource price | 0.8 |
| Iduapriem | Exploration from Blocks 7 and 8, and Block 3W and an increase in the Mineral Resource price | 0.7 |
| Other | Additions less than 0.5Moz | 0.9 |
| Sub-total | 134.9 | |
| Reductions | Due to: | |
| Obuasi | An increase in cost which resulted in higher cut-off grades as well as the sterilisation of stopes in the depletion process | (2.1) |
| North Bullfrog (excluding Acquisition) | Updating methodology changes after the acquisition including prices, costs and updating modifying factors such as process recoveries | (1.0) |
| Other | Reductions less than 0.5Moz | (0.4) |
| Mineral Resource as at 31 December 2022 | 131.4 | |
Copper
The AngloGold Ashanti copper Mineral Resource remained unchanged at 4.26Mt (9,384Mlb) as at 31 December 2022. The Mineral Resource was estimated using a copper price of $3.50/lb, unless otherwise stated (2021: $3.50/lb).
Copper Mineral Resource — year-on-year changes
| Mt | Mlb | ||
|---|---|---|---|
| Mineral Resource as at 31 December 2021 | 4.26 | 9,384 | |
| No changes | Due to: | ||
| Quebradona | Optimisation of the Feasibility Study (FS) is still ongoing and no additional exploration has been completed | – | – |
| Mineral Resource as at 31 December 2022 | 4.26 | 9,384 | |
Mineral Reserve
Gold
The AngloGold Ashanti gold Mineral Reserve increased from 29.8Moz as at 31 December 2021 to 30.4Moz as at 31 December 2022. This annual net increase of 0.6Moz includes additions due to exploration and modelling changes of 2.8Moz, and changes in economic assumptions of 1.0Moz. This increase was partially offset by depletion of 2.9Moz and reductions due to other factors of 0.3Moz. The Mineral Reserve was estimated using a gold price of $1,400/oz, unless otherwise stated (2021: $1,200/oz).
Gold Mineral Reserve — year-on-year changes
| Moz | ||
|---|---|---|
| Mineral Reserve as at 31 December 2021 | 29.8 | |
| Depletions | (2.9) | |
| Sub-total | 26.9 | |
| Additions | Due to: | |
| Geita | Ongoing exploration drilling success resulting in larger pit designs at Nyamulilima and the first-time reporting of the Geita Hill underground Mineral Reserve, as well as an increase in the Mineral Reserve price and reduced cost | 1.5 |
| Siguiri | The first-time reporting of Sorofe, Sanutinti, Kalamagna Mineral Reserve, exploration infill drilling updates and the increase in the Mineral Reserve price combined with the selection of a higher revenue factor shell at Kami and Foulata | 1.0 |
| Kibali | The conversion of the 11000 lode in the Karagba, Chauffeur and Durba (KCD) underground and growth in the Ikamva and Oere pits due to exploration successes together with an increase in the Mineral Reserve price | 0.6 |
| AGA Mineração | Exploration and methodology changes together with an increase in the Mineral Reserve price | 0.3 |
| Other | Additions less than 0.3Moz | 0.6 |
| Sub-total | 30.9 | |
| Reductions | Due to: | |
| Obuasi | Exploration as a result of infill drilling and an increase in mining cost and sustaining capital | (0.3) |
| Other | Reductions less than 0.3Moz | (0.2) |
| Mineral Reserve as at 31 December 2022 | 30.4 | |
Copper
The AngloGold Ashanti copper Mineral Reserve remained unchanged at 1.47Mt (3,250Mlb) as at 31 December 2022. The Mineral Reserve was estimated using a copper price of $2.90/lb, unless otherwise stated (2021: $2.90/lb).
Copper Mineral Reserve — year-on-year changes
| Mt | Mlb | ||
|---|---|---|---|
| Mineral Reserve as at 31 December 2021 | 1.47 | 3,250 | |
| No changes | Due to: | ||
| Quebradona | Optimisation of the FS is still ongoing and no additional exploration has been completed | – | – |
| Mineral Reserve as at 31 December 2022 | 1.47 | 3,250 | |
Note:
The Mineral Resource, as reported, is inclusive of the Mineral Reserve component, unless otherwise stated. Mineral Resource and Mineral Reserve estimates are reported as at 31 December 2022 and are net of 2022 production depletion. To reflect that figures are not precise calculations and that there is uncertainty in their estimation, AngloGold Ashanti reports tonnage, grade and content for gold to two decimals and content for copper with no decimals. Previously AngloGold Ashanti elected to use the term “Ore Reserve” in its reporting. While the term “Mineral Reserve” is used throughout the SAMREC Code, the SAMREC Code recognises that the term “Ore Reserve” is synonymous with the term “Mineral Reserve”. The U.S. Securities and Exchange Commission (SEC) also uses the term “Mineral Reserve” in Subpart 1300 of Regulation S-K (Regulation S-K 1300). AngloGold Ashanti has therefore elected to use the term “Mineral Reserve” going forward to align itself with the terminology used in both the SAMREC Code and Regulation S-K 1300.
By-products
Several by-products are expected to be recovered as a result of processing of the gold Mineral Reserve and copper Mineral Reserve. These include 0.29Mt of sulphur from Brazil, 21.9Moz of silver from Argentina and 28.1Moz of silver from Colombia. Molybdenum, at present, is not planned for recovery at Quebradona. The Quebradona process plant has been designed to treat underground ore and to produce copper concentrate with provision of space in the plant site for a molybdenum plant in the future.
Corporate governance
AngloGold Ashanti has an established Mineral Resource and Mineral Reserve Leadership Team (RRLT) that is responsible for setting and overseeing its Mineral Resource and Mineral Reserve governance framework, and for ensuring that the Company’s goals and objectives are met while complying with all relevant regulatory codes.
The Audit and Risk Committee as well as the Investment Committee of the Company’s Board of Directors (Board), review the Mineral Resource and Mineral Reserve and make a recommendation to the Board, which provides the final approval for the publication of the Mineral Resource and Mineral Reserve estimates.
AngloGold Ashanti has developed and implemented a rigorous system of internal and external reviews aimed at providing assurance in respect of Mineral Resource and Mineral Reserve estimates. In 2022, the following operations and projects were subject to an external review on the basis that each operation or project will be reviewed by an independent third-party on average once every three years:
- Mineral Resource and Mineral Reserve at Geita
- Mineral Resource and Mineral Reserve at Cerro Vanguardia
- Mineral Resource at North Bullfrog Project
External reviews of the Mineral Resource and Mineral Reserve were conducted by SRK Consulting for Geita, by WSP Golder for Cerro Vanguardia and by SLR International Corporation for North Bullfrog. Certificates of sign-off were received for all operations and projects audited to state that the applicable Mineral Resource and Mineral Reserve estimates are reported in accordance with the SAMREC Code.
In addition, numerous internal Mineral Resource and Mineral Reserve process reviews were completed by suitably qualified Competent Persons from within AngloGold Ashanti and no significant deficiencies were identified. The Mineral Resource and Mineral Reserve governance framework is underpinned by appropriate Mineral Resource management processes and protocols that ensure adequate corporate governance. These procedures have been developed to be compliant with the guiding principles of the U.S. Sarbanes-Oxley Act of 2002 (SOX).
AngloGold Ashanti makes use of a web-based Group reporting database called the Resource and Reserve Reporting System (RCubed) for the compilation and authorisation of Mineral Resource and Mineral Reserve reporting. It is a fully integrated system for the reporting and reconciliation of Mineral Resource and Mineral Reserve that supports various regulatory reporting requirements, including the SEC reporting requirements under Regulation S-K 1300, and the JSE reporting requirements under the SAMREC Code. AngloGold Ashanti uses RCubed to ensure a documented chain of responsibility exists from the Competent Persons at the operations to the Company’s RRLT.
AngloGold Ashanti has also developed an enterprise-wide risk management tool that provides consistent and reliable data that allows for visibility of risks and actions across the Group. This tool is used to facilitate, control and monitor material risks to the Mineral Resource and Mineral Reserve, thus ensuring that the appropriate risk management and mitigation plans are in place.
If technical experts involved in the estimation of Mineral Resource or Mineral Reserve feel that their technical advice has been ignored and may represent a risk to the Mineral Resource or Mineral Reserve to be published, they are obliged to inform the RRLT in writing. In addition, AngloGold Ashanti’s “Speak-up” programme can also be used if the technical experts deem they may be compromised in the process.
Competent Persons
The information in this report relating to Exploration Results, Mineral Resource and Mineral Reserve is based on information compiled by or under the supervision of the Competent Persons as defined in the SAMREC Code. All Competent Persons are employed by AngloGold Ashanti, except for Kibali (the Competent Person is employed by Barrick) and Gramalote (the Mineral Resource Competent Person is employed by B2Gold). The Competent Persons have sufficient experience relevant to the style of mineralisation and type of deposit under consideration, and relevant to the activity which they are undertaking. The legal tenure of each operation and project has been verified to the satisfaction of the accountable Competent Person. All the Mineral Reserve has been confirmed to be covered by the required mining permits or there exists a realistic expectation that these permits will be issued. The Competent Persons’ consent to the inclusion of Exploration Results, Mineral Resource and Mineral Reserve information in this report, in the form and context in which it appears.
Accordingly, the Chairperson of the RRLT, Mrs TM Flitton, Master of Engineering (Mining), Bachelor of Science (Honours, Geology), RM SME, Pr.Sci.Nat (SACNASP), FGSSA, assumes responsibility for the Mineral Resource and Mineral Reserve processes for AngloGold Ashanti and is satisfied that the Competent Persons have fulfilled their responsibilities. Mrs TM Flitton has 21 years’ experience in mining with 10 years directly leading and managing Mineral Resource and Mineral Reserve reporting. She is employed full-time by AngloGold Ashanti and can be contacted at the following address: 112 Oxford Road, Houghton Estate, Johannesburg, 2198, South Africa.
A detailed breakdown of our Mineral Resource and Mineral Reserve and backup detail is available on the AngloGold Ashanti website .
View the full comprehensive <R&R> on this website.
Mineral Resource by region, inclusive of Mineral Reserve (attributable)
Gold
| as at 31 December 2022 | Category | Tonnes million | Grade g/t | Contained gold | |
|---|---|---|---|---|---|
| Tonnes | Moz | ||||
| Africa | Measured | 56.67 | 3.14 | 177.73 | 5.71 |
| Indicated | 470.16 | 2.18 | 1,024.96 | 32.95 | |
| Inferred | 201.72 | 3.01 | 607.95 | 19.55 | |
| Total | 728.56 | 2.49 | 1,810.64 | 58.21 | |
| Americas | Measured | 24.08 | 4.28 | 103.10 | 3.31 |
| Indicated | 63.74 | 3.08 | 196.26 | 6.31 | |
| Inferred | 62.07 | 3.58 | 222.03 | 7.14 | |
| Total | 149.90 | 3.48 | 521.39 | 16.76 | |
| Australia | Measured | 60.86 | 1.47 | 89.73 | 2.88 |
| Indicated | 52.72 | 1.85 | 97.47 | 3.13 | |
| Inferred | 55.43 | 2.25 | 124.88 | 4.01 | |
| Total | 169.02 | 1.85 | 312.08 | 10.03 | |
| Projects | Measured | 139.78 | 0.47 | 65.82 | 2.12 |
| Indicated | 1,390.19 | 0.76 | 1,061.64 | 34.13 | |
| Inferred | 682.59 | 0.46 | 314.29 | 10.10 | |
| Total | 2,212.56 | 0.65 | 1,441.76 | 46.35 | |
| AngloGold Ashanti | Measured | 281.39 | 1.55 | 436.37 | 14.03 |
| Indicated | 1,976.82 | 1.20 | 2,380.35 | 76.53 | |
| Inferred | 1,001.82 | 1.27 | 1,269.15 | 40.80 | |
| Total | 3,260.03 | 1.25 | 4,085.87 | 131.36 | |
Copper
| as at 31 December 2022 | Category | Tonnes million | Grade %Cu | Contained copper | |
|---|---|---|---|---|---|
| Tonnes million | Pounds million | ||||
| Projects | Measured | 86.74 | 0.95 | 0.82 | 1,814 |
| Indicated | 227.33 | 0.87 | 1.97 | 4,338 | |
| Inferred | 305.94 | 0.48 | 1.47 | 3,231 | |
| Total | 620.02 | 0.69 | 4.26 | 9,384 | |
| AngloGold Ashanti | Measured | 86.74 | 0.95 | 0.82 | 1,814 |
| Indicated | 227.33 | 0.87 | 1.97 | 4,338 | |
| Inferred | 305.94 | 0.48 | 1.47 | 3,231 | |
| Total | 620.02 | 0.69 | 4.26 | 9,384 | |
Mineral Resource by region, exclusive of Mineral Reserve (attributable)
Gold
| as at 31 December 2022 | Category | Tonnes million | Grade g/t | Contained gold | |
|---|---|---|---|---|---|
| Tonnes | Moz | ||||
| Africa | Measured | 11.14 | 4.23 | 47.19 | 1.52 |
| Indicated | 259.42 | 1.93 | 499.44 | 16.06 | |
| Inferred | 201.72 | 3.01 | 607.95 | 19.55 | |
| Total | 472.29 | 2.44 | 1,154.58 | 37.12 | |
| Americas | Measured | 16.88 | 4.20 | 70.94 | 2.28 |
| Indicated | 41.41 | 2.77 | 114.85 | 3.69 | |
| Inferred | 61.85 | 3.57 | 220.98 | 7.10 | |
| Total | 120.13 | 3.39 | 406.76 | 13.08 | |
| Australia | Measured | 38.85 | 1.44 | 55.96 | 1.80 |
| Indicated | 30.58 | 1.58 | 48.40 | 1.56 | |
| Inferred | 55.36 | 2.25 | 124.79 | 4.01 | |
| Total | 124.79 | 1.84 | 229.15 | 7.37 | |
| Projects | Measured | 98.19 | 0.40 | 38.96 | 1.25 |
| Indicated | 1,249.97 | 0.77 | 958.52 | 30.82 | |
| Inferred | 682.59 | 0.46 | 314.29 | 10.10 | |
| Total | 2,030.75 | 0.65 | 1,311.78 | 42.17 | |
| AngloGold Ashanti | Measured | 165.06 | 1.29 | 213.05 | 6.85 |
| Indicated | 1,581.38 | 1.03 | 1,621.21 | 52.12 | |
| Inferred | 1,001.52 | 1.27 | 1,268.02 | 40.77 | |
| Total | 2,747.97 | 1.13 | 3,102.27 | 99.74 | |
Copper
| as at 31 December 2022 | Category | Tonnes million | Grade %Cu | Contained copper | |
|---|---|---|---|---|---|
| Tonnes million | Pounds million | ||||
| Projects | Measured | 45.15 | 0.69 | 0.31 | 684 |
| Indicated | 148.91 | 0.68 | 1.01 | 2,218 | |
| Inferred | 305.94 | 0.48 | 1.47 | 3,231 | |
| 500.01 | 0.56 | 2.78 | 6,134 | ||
| AngloGold Ashanti | Measured | 45.15 | 0.69 | 0.31 | 684 |
| Indicated | 148.91 | 0.68 | 1.01 | 2,218 | |
| Inferred | 305.94 | 0.48 | 1.47 | 3,231 | |
| Total | 500.01 | 0.56 | 2.78 | 6,134 | |
Mineral Reserve by region (attributable)
Gold
| as at 31 December 2022 | Category | Tonnes million | Grade g/t | Contained gold | |
|---|---|---|---|---|---|
| Tonnes | Moz | ||||
| Africa | Proved | 50.54 | 2.37 | 120.00 | 3.86 |
| Probable | 213.89 | 2.43 | 520.44 | 16.73 | |
| Total | 264.43 | 2.42 | 640.45 | 20.59 | |
| Americas | Proved | 8.16 | 3.39 | 27.64 | 0.89 |
| Probable | 23.64 | 2.79 | 65.88 | 2.12 | |
| Total | 31.80 | 2.94 | 93.53 | 3.01 | |
| Australia | Proved | 21.96 | 1.54 | 33.88 | 1.09 |
| Probable | 22.30 | 2.15 | 47.88 | 1.54 | |
| Total | 44.26 | 1.85 | 81.76 | 2.63 | |
| Projects | Proved | – | – | – | – |
| Probable | 181.81 | 0.71 | 129.98 | 4.18 | |
| Total | 181.81 | 0.71 | 129.98 | 4.18 | |
| AngloGold Ashanti | Proved | 80.66 | 2.25 | 181.53 | 5.84 |
| Probable | 441.64 | 1.73 | 764.18 | 24.57 | |
| Total | 522.29 | 1.81 | 945.71 | 30.41 | |
Copper
| as at 31 December 2022 | Category | Tonnes million | Grade %Cu | Contained copper | |
|---|---|---|---|---|---|
| Tonnes million | Pounds million | ||||
| Projects | Proved | – | – | – | – |
| Probable | 120.01 | 1.23 | 1.47 | 3,250 | |
| Total | 120.01 | 1.23 | 1.47 | 3,250 | |
| AngloGold Ashanti | Proved | – | – | – | – |
| Probable | 120.01 | 1.23 | 1.47 | 3,250 | |
| Total | 120.01 | 1.23 | 1.47 | 3,250 | |
