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Reserves and resources
as per September 2009 resource statement
The following tables summarises the resource and reserve status of Petra and its various operations as at 30 June 2009:
| Category | Gross | Net attributable | ||||
|---|---|---|---|---|---|---|
| Tonnes (millions) | Grade (cpht) | Contained Diamonds (millions) | Tonnes (millions) | Grade (cpht) | Contained Diamonds (Mcts) | |
| Diamond reserves per assets | ||||||
| Proven | 19.266 | 7.19 | 1.385 | 13.819 | 8.41 | 1.162 |
| Probable | 40.256 | 23.63 | 9.514 | 29.553 | 21.69 | 7.299 |
| Sub-total | 59.522 | 18.31 | 10.899 | 43.352 | 16.86 | 8.460 |
| Diamond resources per asset | ||||||
| Measured | – | – | – | – | – | – |
| Indicated | 363.683 | 51.89 | 188.699 | 444.691 | 41.22 | 139.644 |
| Inferred | 1,208.946 | 5.18 | 62.655 | 900.327 | 4.89 | 47.234 |
| Sub-total | 1,572.629 | 15.98 | 251.354 | 1,169.875 | 11.17 | 186.878 |
| Total | 262.253 | 195.338 | ||||
Notes
- “cpht” – carats per hundred tonnes; “mcts” – millions of carats
South Africa
Cullinan
| Category | Gross | Net attributable | ||||
|---|---|---|---|---|---|---|
| Tonnes (millions) | Grade (cpht) | Contained Diamonds (millions) | Tonnes (millions) | Grade (cpht) | Contained Diamonds (Mcts) | |
| Diamond reserves per assets | ||||||
| Proven | – | – | – | – | – | – |
| Probable | 14.533 | 38.27 | 5.562 | 10.754 | 38.27 | 4.116 |
| Sub-total | 14.533 | 38.27 | 5.562 | 10.754 | 38.27 | 4.116 |
| Diamond resources per asset | ||||||
| Measured | – | – | – | – | – | – |
| Indicated | 255.144 | 71.44 | 182.279 | 188.806 | 71.44 | 134.886 |
| Inferred | 166.447 | 10.04 | 16.716 | 123.17 | 10.04 | 12.37 |
| Sub-total | 421.591 | 47.20 | 198.994 | 311.978 | 47.20 | 147.256 |
| Total | 204.556 | 151.372 | ||||
Notes:
- Resource tonnes and grade based on block cave depletion modeling, and include external waste.
- Reserve carats and grades are factorised as per the following plant liberation factors: "Brown" kimberlite 75.8%, "Grey" kimberlite 71.4%, and Hypabbysal kimberlite 71.8%.
- Resource bottom cut-off: 1mm
- Reserve bottom cut off: 1.2mm
Koffiefontein
| Category | Gross | Net attributable | ||||
|---|---|---|---|---|---|---|
| Tonnes (millions) | Grade (cpht) | Contained Diamonds (millions) | Tonnes (millions) | Grade (cpht) | Contained Diamonds (Mcts) | |
| Diamond reserves per assets | ||||||
| Proven | 17.660 | 3.50 | 0.619 | 12.362 | 3.50 | 0.433 |
| Probable | 18.482 | 8.76 | 1.618 | 12.938 | 8.76 | 1.133 |
| Sub-total | 36.143 | 6.19 | 2.237 | 25.300 | 6.19 | 1.566 |
| Diamond resources per asset | ||||||
| Measured | – | – | – | – | – | – |
| Indicated | 12.440 | 7.84 | 0.976 | 8.708 | 7.84 | 0.683 |
| Inferred | 90.417 | 3.04 | 2.751 | 63.292 | 3.04 | 1.926 |
| Sub-total | 102.857 | 3.62 | 3.727 | 72.000 | 3.62 | 2.609 |
| Total | 5.964 | 4.175 | ||||
Notes:
- Resource bottom cut-off (Koffiefontein underground and Ebenheazer): 0.5mm
- Resource bottom cut-off (Eskom tailings):1mm
- Reserve bottom cut-off: 1.2mm
Kimberley underground
| Category | Gross | Net attributable | ||||
|---|---|---|---|---|---|---|
| Tonnes (millions) | Grade (cpht) | Contained Diamonds (millions) | Tonnes (millions) | Grade (cpht) | Contained Diamonds (Mcts) | |
| Diamond reserves per assets | ||||||
| Proven | – | – | – | – | – | – |
| Probable | 5.006 | 19.94 | 0.998 | 3.705 | 19.94 | 0.739 |
| Sub-total | 5.006 | 19.94 | 0.998 | 3.705 | 19.94 | 0.739 |
| Diamond resources per asset | ||||||
| Measured | – | – | – | – | – | – |
| Indicated | 4.146 | 20.22 | 0.839 | 3.068 | 20.22 | 0.620 |
| Inferred | 50.113 | 10.27 | 5.147 | 37.084 | 10.27 | 3.809 |
| Sub-total | 54.259 | 11.03 | 5.986 | 40.152 | 11.03 | 4.429 |
| Total | 6.984 | 5.168 | ||||
Notes:
- Resource bottom cut-off (Dutoitspan West Extension): 1mm
- Resource bottom cut-off (all other underground blocks): 0.5mm
- Reserve bottom cut-off: 1.2mm
Fissure Mines combined (Helam, Sedibeng, Star)
| Category | Gross | Net attributable | ||||
|---|---|---|---|---|---|---|
| Tonnes (millions) | Grade (cpht) | Contained Diamonds (millions) | Tonnes (millions) | Grade (cpht) | Contained Diamonds (Mcts) | |
| Diamond reserves per assets | ||||||
| Proven | 1.606 | 47.70 | 0.766 | 1.457 | 50.02 | 0.729 |
| Probable | 2.235 | 59.76 | 1.335 | 2.137 | 61.35 | 1.311 |
| Sub-total | 3.840 | 54.72 | 2.101 | 3.594 | 56.76 | 2.040 |
| Diamond resources per asset | ||||||
| Measured | – | – | – | – | – | – |
| Indicated | – | – | – | – | – | – |
| Inferred | 1.488 | 173.57 | 2.583 | 1.421 | 178.50 | 2.536 |
| Sub-total | 1.488 | 173.57 | 2.583 | 1.421 | 178.50 | 2.536 |
| Total | 4.684 | 4.575 | ||||
Notes:
- Resource bottom cut-off: 1mm
- Reserve bottom cut-off: 1.2mm
- Measured resources are classified as 1 level below current workings, or where a block is bounded above and below by current workings
- Indicated resources are classified as 2 levels below measured resources
- Inferred resources are classified as 3 levels below indicated resources
- Measured and indicated resources have been converted to reserves by applying historically derived external dilution and in-stope loss factors to resource tonnages and grades.
Tanzania
Williamson mine
| Category | Gross | Net attributable | ||||
|---|---|---|---|---|---|---|
| Tonnes (millions) | Grade (cpht) | Contained Diamonds (millions) | Tonnes (millions) | Grade (cpht) | Contained Diamonds (Mcts) | |
| Diamond reserves per assets | ||||||
| Proven | – | – | – | – | – | – |
| Probable | – | – | – | – | – | – |
| Sub-total | – | – | – | – | – | – |
| Diamond resources per asset | ||||||
| Measured | – | – | – | – | – | – |
| Indicated | 91.952 | 5.01 | 4.606 | 68.964 | 5.01 | 3.455 |
| Inferred | 900.481 | 3.94 | 35.457 | 675.361 | 3.94 | 26.593 |
| Sub-total | 992.433 | 4.04 | 40.064 | 744.325 | 4.04 | 30.048 |
| Total | 40.064 | 30.048 | ||||
Notes
- Resource bottom cut-off:1mm
General Notes on reporting Criteria
- Resources are reported exclusive of reserves.
- Tonnes are reported as millions. Contained diamonds are reported as millions of carats (mcts)
- Tonnes are metric tonnes, and are rounded to the nearest 1000 tonnes. Carats are rounded to the nearest 1000 carats. Rounding off of numbers may result in minor computational discrepancies.
- Resource tonnages and grades are reported exclusive of internal waste, unless where otherwise stated.
- Reserve tonnages and grades are reported inclusive of external waste, mining and geological losses and plant modifying factors. Reserve carats will be less than resource carats on conversion and this has been taken into account in the applicable statements
Notes
The annual resource and reserve statements for Petra shown above are based on information compiled internally within the Group under the guidance and supervision of Jim Davidson, Pr. Sci. Nat. (reg. No.400031/06). Jim Davidson is the qualified person for the purposes of the AIM guidance note on Mining, Oil and Gas companies (2006). Jim Davidson has over 30 years relevant experience in the diamond industry, and is a full-time employee of Petra.
All resources and reserves have been independently verified by Patrick Bartlett, Pr.Sci. Nat. (reg. No. 400060/87), a competent person with over 30 years of relevant experience in the diamond mining industry. Resources and reserves have been reported in accordance with the South African code for the reporting of mineral resources and mineral reserves (SAMREC 2007).
