Mineral Resource and Ore Reserve
– a summary
CREATING VALUE
BY GROWING THE MAJOR ASSET
AngloGold Ashanti‘s Mineral Resource and Ore Reserve are reported in accordance with the minimum standards described by the Australasian Code for Reporting of Exploration Results, Mineral Resource and Ore Reserve (The JORC Code, 2004 edition), and also conform to the standards set out in the South African Code for the Reporting of Exploration Results, Mineral Resources and Mineral Reserves (The SAMREC Code, 2007 edition). The Mineral Resource is inclusive of the Ore Reserve component unless otherwise stated. AngloGold Ashanti has in place all the necessary statutory mining authorisations and permits in the jurisdictions where it operates to mine for, or explore for, declared materials, or has a reasonable expectation of such mining authorisations and permits being granted.
AngloGold Ashanti strives to actively create value by growing its major asset – the Mineral Resource and Ore Reserve. This drive is based on an active, well-defined brownfields exploration programme, innovation in both geological modelling and mine planning, and continual optimisation of its asset portfolio.
Mineral Resource
The total Mineral Resource increased from 220.0Moz in December 2010 to 230.9Moz in December 2011. A gross annual increase of 16.8Moz occurred before depletion and while the net increase after allowing for depletion was 10.9Moz, changes in economic assumptions from December 2010 to December 2011 resulted in an 11.2Moz increase to the Mineral Resource, while exploration and modelling resulted in an increase of 7.9Moz. The remaining decrease of 2.2Moz resulted from various other factors. Depletion from the Mineral Resource for the year totalled 6.0Moz. The Mineral Resource was estimated at a gold price of $1,600/oz (2010: $1,100/oz).
Ore Reserve
The AngloGold Ashanti Ore Reserve increased from 71.2Moz in December 2010 to 75.6Moz in December 2011. A gross annual increase of 9.6Moz occurred before depletion of 5.2Moz. The increase net of depletion was therefore 4.4Moz. Changes in economic assumptions from 2010 to 2011 resulted in an increase of 4.4Moz to the Ore Reserve, while exploration and modelling resulted in a further increase of 5.0Moz. The remaining increase of 0.2Moz resulted from various other factors.
The Ore Reserve was calculated using a gold price of $1,100/oz (2010: $850/oz).
By-products
Several by-products are recovered as a result of the processing of the gold Ore Reserve. In 2011, the by-product Ore Reserve included 57,299t of uranium oxide from the South African operations, 408,348t of sulphuric acid from Brazil and 46.9Moz of silver from Argentina.
Competent persons
The information in this report relating to exploration results, Mineral Resource and Ore Reserve is based on information compiled by the Competent Persons. The Competent Persons consent to the inclusion of exploration results, Mineral Resource and Ore Reserve information in this report, in the form and context in which it appears.
During the past decade, the company has developed and implemented a rigorous system of internal and external reviews of exploration results, Mineral Resource and Ore Reserve. A documented chain of responsibility exists from the Competent Persons at the operations to the company's Mineral Resource and Ore Reserve Steering Committee. Accordingly, the chairman of the Mineral Resource and Ore Reserve Steering Committee, VA Chamberlain, MSc (Mining Engineering), BSc (Hons) (Geology), MGSSA, FAusIMM, assumes responsibility for the Mineral Resource and Ore Reserve processes for AngloGold Ashanti and is satisfied that the Competent Persons have fulfilled their responsibilities. Mr Chamberlain can be contacted at 76 Jeppe Street, Newtown, 2001, South Africa.
A more detailed breakdown of AngloGold Ashanti‘s Mineral
Resource and Ore Reserve is provided in the 
Mineral Resource and Ore Reserve Report 2011 (PDF - 3.91MB).
| Mineral Resource | Moz | |
|---|---|---|
| Mineral Resource as at 31 December 2010 | 220.0 | |
| Reductions | ||
| Great Noligwa | Mineral Resource reduced due to increased costs | (0.6) |
| Other | Total of non-significant changes | (1.8) |
| Additions | ||
| Tropicana | Exploration success in the underground project | 0.8 |
| Gramalote | Exploration success at Trinidad | 0.9 |
| Kopanang | Grade increased as a result of exploration | 1.1 |
| Geita | Combined effect of price and estimation | 1.3 |
| Iduapriem | Improved Mineral Resource price | 1.3 |
| Obuasi | Improved Mineral Resource price | 2.3 |
| La Colosa | Exploration success | 3.8 |
| Other | Total of non-significant changes | 1.7 |
| Mineral Resource as at 31 December 2011 | 230.9 |
| Ore Reserve | Moz | |
|---|---|---|
| Ore Reserve as at 31 December 2010 | 71.2 | |
| Reductions | ||
| Moab Khotsong | Depletion and minor model revision | (0.5) |
| Other | Total of non-significant changes | (1.1) |
| Additions | ||
| Geita | Improved Ore Reserve price | 0.5 |
| Cripple Creek & Victor | Mine life extension added to Ore Reserve | 0.5 |
| Vaal River surface operations | Technical studies showed that the economic extraction of gold and uranium from the tailings is viable |
3.2 |
| Other | Total of non-significant changes | 1.7 |
| Ore Reserve as at 31 December 2011 | 75.6 |
Rounding of numbers may result in computational discrepancies.
| Contained gold | |||||
|---|---|---|---|---|---|
| As at 31 December 2011 | Category | Tonnes million | Grade g/t | Tonnes | Moz |
| South Africa | Measured | 25.98 | 15.76 | 409.39 | 13.16 |
| Indicated | 799.63 | 2.57 | 2,056.44 | 66.12 | |
| Inferred | 38.30 | 14.91 | 570.81 | 18.35 | |
| Total | 863.91 | 3.52 | 3,036.65 | 97.63 | |
| Democratic Republic of the Congo | Measured | – | – | – | – |
| Indicated | 62.41 | 3.66 | 228.64 | 7.35 | |
| Inferred | 33.16 | 2.90 | 96.07 | 3.09 | |
| Total | 95.57 | 3.40 | 324.71 | 10.44 | |
| Ghana | Measured | 89.38 | 4.64 | 414.35 | 13.32 |
| Indicated | 97.81 | 3.42 | 334.74 | 10.76 | |
| Inferred | 136.86 | 3.26 | 446.65 | 14.36 | |
| Total | 324.04 | 3.69 | 1,195.74 | 38.44 | |
| Guinea | Measured | 37.19 | 0.62 | 22.96 | 0.74 |
| Indicated | 116.48 | 0.73 | 85.09 | 2.74 | |
| Inferred | 67.18 | 0.79 | 53.17 | 1.71 | |
| Total | 220.85 | 0.73 | 161.22 | 5.18 | |
| Mali | Measured | 12.65 | 1.31 | 16.57 | 0.53 |
| Indicated | 62.66 | 1.57 | 98.24 | 3.16 | |
| Inferred | 36.58 | 1.04 | 37.96 | 1.22 | |
| Total | 111.89 | 1.37 | 152.77 | 4.91 | |
| Namibia | Measured | 18.35 | 0.71 | 13.10 | 0.42 |
| Indicated | 99.78 | 1.22 | 122.04 | 3.92 | |
| Inferred | 16.41 | 1.15 | 18.88 | 0.61 | |
| Total | 134.54 | 1.14 | 154.01 | 4.95 | |
| Tanzania | Measured | – | – | – | – |
| Indicated | 106.42 | 2.74 | 291.44 | 9.37 | |
| Inferred | 33.55 | 2.97 | 99.50 | 3.20 | |
| Total | 139.96 | 2.79 | 390.94 | 12.57 | |
| Australia | Measured | 35.13 | 1.71 | 60.01 | 1.93 |
| Indicated | 50.11 | 2.56 | 128.48 | 4.13 | |
| Inferred | 11.05 | 3.92 | 43.28 | 1.39 | |
| Total | 96.29 | 2.41 | 231.77 | 7.45 | |
| Argentina | Measured | 11.98 | 1.61 | 19.30 | 0.62 |
| Indicated | 26.09 | 3.40 | 88.76 | 2.85 | |
| Inferred | 9.14 | 3.17 | 29.01 | 0.93 | |
| Total | 47.22 | 2.90 | 137.08 | 4.41 | |
| Brazil | Measured | 10.53 | 6.31 | 66.44 | 2.14 |
| Indicated | 16.41 | 5.74 | 94.23 | 3.03 | |
| Inferred | 36.93 | 6.30 | 232.73 | 7.48 | |
| Total | 63.88 | 6.16 | 393.40 | 12.65 | |
| Colombia | Measured | 15.56 | 0.85 | 13.24 | 0.43 |
| Indicated | 33.97 | 0.79 | 26.98 | 0.87 | |
| Inferred | 564.78 | 0.93 | 527.63 | 16.96 | |
| Total | 614.31 | 0.92 | 567.85 | 18.26 | |
| United States | Measured | 280.58 | 0.78 | 217.65 | 7.00 |
| Indicated | 227.03 | 0.68 | 155.09 | 4.99 | |
| Inferred | 96.04 | 0.65 | 62.16 | 2.00 | |
| Total | 603.65 | 0.72 | 434.90 | 13.98 | |
| Total | Measured | 537.33 | 2.33 | 1,253.01 | 40.29 |
| Indicated | 1,698.79 | 2.18 | 3,710.18 | 119.29 | |
| Inferred | 1,079.98 | 2.05 | 2,217.85 | 71.31 | |
| Total | 3,316.10 | 2.17 | 7,181.04 | 230.88 | |
Rounding of numbers may result in computational discrepancies
| Contained gold | |||||
|---|---|---|---|---|---|
| As at 31 December 2011 | Category | Tonnes million | Grade g/t | Tonnes | Moz |
| South Africa | Measured | 15.36 | 16.99 | 261.03 | 8.39 |
| Indicated | 230.15 | 4.01 | 923.55 | 29.69 | |
| Inferred | 16.98 | 21.15 | 358.97 | 11.54 | |
| Total | 262.49 | 5.88 | 1,543.56 | 49.63 | |
| Democratic Republic of the Congo | Measured | – | – | – | – |
| Indicated | 28.97 | 3.04 | 87.97 | 2.83 | |
| Inferred | 33.16 | 2.90 | 96.07 | 3.09 | |
| Total | 62.13 | 2.96 | 184.03 | 5.92 | |
| Ghana | Measured | 20.74 | 5.15 | 106.80 | 3.43 |
| Indicated | 64.26 | 3.63 | 233.54 | 7.51 | |
| Inferred | 136.67 | 3.27 | 446.64 | 14.36 | |
| Total | 221.66 | 3.55 | 786.98 | 25.30 | |
| Guinea | Measured | 0.83 | 0.54 | 0.45 | 0.01 |
| Indicated | 41.37 | 0.74 | 30.64 | 0.99 | |
| Inferred | 67.18 | 0.79 | 53.17 | 1.71 | |
| Total | 109.39 | 0.77 | 84.26 | 2.71 | |
| Mali | Measured | 4.73 | 0.86 | 4.09 | 0.13 |
| Indicated | 31.26 | 1.26 | 39.43 | 1.27 | |
| Inferred | 36.58 | 1.04 | 37.96 | 1.22 | |
| Total | 72.57 | 1.12 | 81.48 | 2.62 | |
| Namibia | Measured | 7.57 | 0.53 | 4.01 | 0.13 |
| Indicated | 53.86 | 1.06 | 56.88 | 1.83 | |
| Inferred | 16.41 | 1.15 | 18.88 | 0.61 | |
| Total | 77.85 | 1.02 | 79.77 | 2.56 | |
| Tanzania | Measured | – | – | – | – |
| Indicated | 50.59 | 2.84 | 143.72 | 4.62 | |
| Inferred | 33.55 | 2.97 | 99.50 | 3.20 | |
| Total | 84.14 | 2.89 | 243.22 | 7.82 | |
| Australia | Measured | 2.27 | 0.58 | 1.32 | 0.04 |
| Indicated | 18.02 | 2.78 | 50.18 | 1.61 | |
| Inferred | 10.72 | 3.99 | 42.78 | 1.38 | |
| Total | 31.02 | 3.04 | 94.28 | 3.03 | |
| Argentina | Measured | 2.80 | 2.08 | 5.81 | 0.19 |
| Indicated | 22.22 | 2.13 | 47.28 | 1.52 | |
| Inferred | 9.14 | 3.17 | 29.01 | 0.93 | |
| Total | 34.16 | 2.40 | 82.11 | 2.64 | |
| Brazil | Measured | 2.86 | 7.39 | 21.13 | 0.68 |
| Indicated | 7.02 | 6.53 | 45.82 | 1.47 | |
| Inferred | 35.80 | 6.37 | 228.05 | 7.33 | |
| Total | 45.67 | 6.46 | 295.00 | 9.48 | |
| Colombia | Measured | 15.56 | 0.85 | 13.24 | 0.43 |
| Indicated | 33.97 | 0.79 | 26.98 | 0.87 | |
| Inferred | 564.78 | 0.93 | 527.63 | 16.96 | |
| Total | 614.31 | 0.92 | 567.85 | 18.26 | |
| United States | Measured | 119.80 | 0.71 | 85.17 | 2.74 |
| Indicated | 140.43 | 0.66 | 93.03 | 2.99 | |
| Inferred | 82.15 | 0.66 | 54.08 | 1.74 | |
| Total | 342.39 | 0.68 | 232.28 | 7.47 | |
| Total | Measured | 192.52 | 2.61 | 503.06 | 16.17 |
| Indicated | 722.13 | 2.46 | 1,779.02 | 57.20 | |
| Inferred | 1,043.12 | 1.91 | 1,992.74 | 64.07 | |
| Total | 1,957.76 | 2.18 | 4,274.82 | 137.44 | |
Rounding of numbers may result in computational discrepancies
| Contained gold | |||||
|---|---|---|---|---|---|
| As at 31 December 2011 | Category | Tonnes million | Grade g/t | Tonnes | Moz |
| South Africa | Proved | 11.89 | 8.85 | 105.17 | 3.38 |
| Probable | 573.65 | 1.57 | 903.41 | 29.05 | |
| Total | 585.54 | 1.72 | 1,008.58 | 32.43 | |
| Democratic Republic of the Congo | Proved | – | – | – | – |
| Probable | 33.44 | 4.21 | 140.69 | 4.52 | |
| Total | 33.44 | 4.21 | 140.69 | 4.52 | |
| Ghana | Proved | 42.73 | 3.08 | 131.77 | 4.24 |
| Probable | 53.94 | 4.43 | 239.06 | 7.69 | |
| Total | 96.67 | 3.84 | 370.83 | 11.92 | |
| Guinea | Proved | 35.72 | 0.61 | 21.90 | 0.70 |
| Probable | 72.18 | 0.69 | 49.97 | 1.61 | |
| Total | 107.90 | 0.67 | 71.87 | 2.31 | |
| Mali | Proved | 5.20 | 1.91 | 9.93 | 0.32 |
| Probable | 43.13 | 1.56 | 67.20 | 2.16 | |
| Total | 48.33 | 1.60 | 77.13 | 2.48 | |
| Namibia | Proved | 6.31 | 1.09 | 6.88 | 0.22 |
| Probable | 44.18 | 1.29 | 56.88 | 1.83 | |
| Total | 50.49 | 1.26 | 63.76 | 2.05 | |
| Tanzania | Proved | – | – | – | – |
| Probable | 55.81 | 2.64 | 147.11 | 4.73 | |
| Total | 55.81 | 2.64 | 147.11 | 4.73 | |
| Australia | Proved | 32.86 | 1.79 | 58.69 | 1.89 |
| Probable | 28.98 | 2.55 | 73.95 | 2.38 | |
| Total | 61.84 | 2.14 | 132.64 | 4.26 | |
| Argentina | Proved | 10.56 | 1.35 | 14.30 | 0.46 |
| Probable | 12.85 | 4.25 | 54.64 | 1.76 | |
| Total | 23.41 | 2.95 | 68.94 | 2.22 | |
| Brazil | Proved | 7.01 | 5.51 | 38.65 | 1.24 |
| Probable | 7.84 | 4.68 | 36.65 | 1.18 | |
| Total | 14.85 | 5.07 | 75.30 | 2.42 | |
| Colombia | Proved | 160.78 | 0.82 | 132.48 | 4.26 |
| Probable | 86.60 | 0.72 | 62.06 | 2.00 | |
| Total | 247.38 | 0.79 | 194.54 | 6.25 | |
| Total | Proved | 313.07 | 1.66 | 519.78 | 16.71 |
| Probable | 1,012.60 | 1.81 | 1,831.63 | 58.89 | |
| Total | 1,325.67 | 1.77 | 2,351.40 | 75.60 | |
Rounding of numbers may result in computational discrepancies