ore reserves and mineral resources 2011 report - Anglo American ...

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SECURING OUR FUTURE ORE RESERVE AND MINERAL RESOURCE ESTIMATES as at 31 December 2011 MINERAL RESOURCES BY PROJECT Mineral Resources inclusive of Ore Reserves (3E) The figures in the table below represent Anglo American Platinum Limited’s (Amplats) attributable interests: Resources Contained Project million Grade Grade Grade Contained 3E million (AAPL interest) tonnes 3E g/t % Cu % Ni 3E tonnes troy ounces SOUTH AFRICA Boikgantsho Project Measured (49%)* Indicated 37.0 1.30 0.07 0.11 47.9 1.5 Measured and Indicated 37.0 1.30 0.07 0.11 47.9 1.5 Inferred 1.8 1.14 0.04 0.08 2.1 0.1 Total 38.8 1.29 0.07 0.10 49.9 1.6 Sheba’s Ridge Project Measured 28.0 0.88 0.07 0.20 24.6 0.8 (35%)* Indicated 34.0 0.85 0.07 0.18 29.1 0.9 Measured and Indicated 62.0 0.87 0.07 0.19 53.6 1.7 Inferred 149.9 0.96 0.08 0.19 144.5 4.6 Total 211.9 0.94 0.08 0.19 198.2 6.4 AMERICAS Pedra Branca – Brazil (51%)* Inferred 6.6 2.27 0.03 0.23 15.0 0.5 * Not included in regional Mineral Resources. Total 6.6 2.27 0.03 0.23 15.0 0.5 Rounding of figures may result in computational discrepancies. Figures not included in the global Mineral Resource summary. 3E grade reported: sum of platinum, palladium and gold grades. Boikgantsho Sheba’s Ridge Pedra Branca Amplats and Anooraq Resources hold a 49% and 51% interest in Boikgantsho respectively. The figures quoted are for the attributable interest. During 2011, a new Resource evaluation was completed by Amplats. Significant changes to the previous estimates conducted in 2004 are owing to: A cut-off grade of 1 g/t (3E) was applied (as used at Mogalakwena Platreef (1 g/t 4E)). Exclusion of oxidised material up to a depth of 40 m. The Resource evaluation reported to a depth of 300 m below surface. Excludes losses owing to the major dykes and a swathe of 200 m either side of the major Drenthe fault, which has a horizontal displacement of approximately 2.2 km. Amplats, Industrial Development Corporation (IDC) and Aquarius South Africa hold a 35%, 26% and 39% interest in Sheba’s Ridge respectively. During 2011, a new Resource evaluation was completed by external consultants on behalf of Aquarius Platinum South Africa. Reinterpretation of the geology, together with structural complexity, resulted in a revised model with a significant decrease of the Resource classification confidence. Additionally, the reporting depth below surface has been reduced. It must be noted that since 2011 the joint-venture area encompasses all prospects rights of the Sheba’s Ridge Project. The geological loss increased from a previously used 0.5% to 5% within the Measured category and to 10% within the Indicated and Inferred category. Previously, the cut-off grade used was $10.5/t recoverable value, a figure supplied by Ridge Mining using metal price projections and metallurgical recoveries. This was changed to 0.5 g/t (3E) in the current model. Amplats and Solitario hold a 51% and 49% interest in Pedra Branca respectively. The figure quoted is for the attributable interest. A cut-off of 0.7 g/t (3E) was used. River Valley In previous years Amplats held an attributable interest of 50%. During 2011, Pacific North West Capital Corporation purchased the remaining 50% interest in the unincorporated joint venture covering the River Valley Project from Amplats. As a consequence the Mineral Resources are now excluded. 34 ANGLO AMERICAN PLATINUM LIMITED 2011
MINERAL DEPOSITS General Surface material In addition to the evaluated and reported Ore Reserves and Mineral Resources, Amplats holds various Mineral Deposits that are not publicly reported. Different types of Mineral Deposits exist, either stockpiled material on surface or still in situ underground. This material requires studies to determine the potential economic value (reasonable and realistic prospects for eventual economic extraction). Surface material is subdivided into tailings dams, stockpiles or rock dumps. Tailings dams Tailings dams Ore Reserves and Mineral Resources, where evaluated, are already reported in the relevant Ore Reserve and Mineral Resource statement. Tailings dams Mineral Deposit: Operating (active) tailings dams for current mining operations cannot be geologically assessed and therefore are not reported as part of the Mineral Resources. They contain residual amounts of PGE and base metals and are registered internally in Amplats’ asset books. Currently significant Mineral Deposits are available at the following operations: – Rustenburg mines, Amandelbult mines, Mogalakwena Mine, Union Mine and BRPM, and in the East Bushveld at Modikwa and Bokoni mines. Stockpiles Stockpiles are mined ore being held for future treatment. Currently only Mogalakwena reports Ore Reserve and Mineral Resource stockpiles. These Ore Reserves and Mineral Resources are already reported in the relevant Ore Reserve and Mineral Resource statement. Rock dumps Rock dumps are not evaluated and are currently not reported under the Ore Reserve and Mineral Resource statement. Exploitation of several rock dumps at Rustenburg mines have been contracted to external private companies who are removing/ depleting the rock dumps in an effort to rehabilitate the land or for crushing or building purposes. Evaluation of low-grade rock dumps not contracted to external companies is ongoing. They contain various amounts of PGE and base metals and are recorded internally. Currently Mineral Deposits have been identified at Rustenburg and Amandelbult mines and at Union Mine. However, minor rock dumps also exist on other operations. Securing our future Underground in situ material Mogalakwena Mine It must be noted that the Mineral Resources are quoted over the entire Mining Right and Prospecting Right areas except for Mogalakwena Mine, where the Mineral Resources are only quoted down to potential future surface mining depths. Unki Platinum Mine (Zimbabwe) Currently only the Unki Platinum Mine Ore Reserves and Mineral Resources have been reported in the relevant Ore Reserve and Mineral Resource statement. Additional Mineral Deposits are contained to the north and to the south of the Unki Platinum Mine. During 2011, a new Resource evaluation was completed covering Unki South, Helvetia and Paarl projects (contained within the special mining lease held by Southridge Limited), however, an independent external review of these Mineral Resources is outstanding and will only be completed during the first quarter of 2012. For this annual report the Mineral Resources reported restate the Unki East and West mines’ Resources. Virgin rock temperature above 75° Celsius Investigations conducted in 2011 to determine maximum mining depths related to virgin rock temperatures have been concluded. A virgin rock temperature of 75° Celsius is currently considered to be the limit to mining given anticipated technology, metal prices and energy costs. The affected portion of the Inferred Mineral Resources within the mining rights of Tumela Mine, Twickenham Mine and Ga-Phasha Project are therefore reclassified as Mineral Deposit within the Amplats portfolio. They comprise the following: Tumela Mine Merensky Reef – portions of Goevernements Plaats 417 KQ: -26.6 Mt -6.7 Moz. Tumela Mine UG2 Reef – portions of Goevernements Plaats 417 KQ: -36.6 Mt -6.7 Moz. Twickenham Platinum Mine UG2 Reef – portions of Balmoral 508 KS: -22.4 Mt -4.0 Moz. Ga-Phasha Project – Merensky Reef: portions of Avoca 472 KS and De Kamp 507 KS: -0.2 Mt -0.04 Moz (attributable interest). Ga-Phasha Project – UG2 Reef: portions of Avoca 472 KS and De Kamp 507 KS: -42.9 Mt -8.6 Moz (attributable interest). Total for both reefs: -128.7 Mt -26.1 Moz. Anglo American Platinum will review these deposits with changing mining technology and metal prices. ANGLO AMERICAN PLATINUM LIMITED 2011 35
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