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VANCOUVER, BRITISH COLUMBIA–(Marketwire – Nov. 10, 2011) – Aura Minerals Inc. (TSX:ORA) (“Aura Minerals” or the “Company”) announces updated resource and reserve estimates for the São Francisco Mine and São Vicente Mine (the “Brazilian Mines”) in Mato Grosso State, Brazil.
As was indicated in the Company’s Annual Information Form dated March 30, 2011, as well as the technical reports dated March 30, 2011 in respect of each of the Brazilian Mines1,2, studies have shown that the reconciliation between the mineral resource models and mine production required further investigation as the Brazilian Mines produced more ore tonnes at lower grades than was predicted by the mineral resource models. As a result, Rogerio Moreno, AusIMM, of MCB Serviços e Mineração Ltda. (“MCB”), the independent Qualified Person for the above-mentioned technical reports, recommended that the mineral resource models be updated and the estimation parameters modified to improve the reconciliation.
1 National Instrument 43-101 compliant technical report dated March 30, 2011, and entitled “Resources and Reserves on the São Francisco Mine in the Municipality of Vila Bela da Santissima Trindade, State of Mato Grosso, Brazil” prepared for Aura Minerals by Rogerio Moreno, AusIMM, of MCB Serviços e Mineração Ltda. (the “São Francisco Technical Report”), a copy of which may be found on SEDAR at www.sedar.com.
2 National Instrument 43-101 compliant technical report dated March 30, 2011, and entitled “Resources and Reserves on the São Vicente Mine in the Municipality of Nova Lacerda, State of Mato Grosso, Brazil” prepared for Aura Minerals by Rogerio Moreno, AusIMM, of MCB Serviços e Mineração Ltda. (the “São Vicente Technical Report”), a copy of which may be found on SEDAR at www.sedar.com.
In updating the mineral resource and reserve estimates for each of the Brazilian Mines, the Company has reinterpreted the geological models used to estimate the mineral resources and reserves. This has resulted in new geological block models that are more tightly constrained to current drilling data and better reflect the discontinuous nature of the mineralization at each mine. Through this process, the Company has developed a new mine plan for each Brazilian Mine to improve reconciliation and confidence in the mine plan production forecasts. However, the reinterpretation of the geological models and the use of updated mine design parameters, including higher cut-off grades reflecting current operating experience, have resulted in a reduction in the mineral resource and reserve estimates at the Brazilian Mines.
The Company has informed the Departamento Nacional de Produção Mineral in Brazil (the Ministry of Mines department responsible for the management of mineral resources) of the changes to the mineral resource and reserve estimates and will be seeking approval of the new mine plans, where required.
Updated Resource and Reserve Estimate at the São Vicente Mine
As stated above, the reinterpretation of the geological model and the use of updated mine design parameters, including a higher mineral resource and reserve cut-off grade of 0.25 g/t gold for dump leach ore (“DLO”) and 0.40 g/t gold for crushed gravity ore (“CGO”), have resulted in a reduction in the mineral resource and reserve estimates at the São Vicente Mine.
Table 1 below presents the updated mineral resource estimate for the São Vicente Mine at a 0.25 g/t gold cut-off for DLO and 0.40 g/t gold cut-off for CGO as compared to the December 31, 2010 resource estimate3 at a 0.13 g/t gold cut-off. Table 2 presents the updated mineral reserve estimate at a 0.25 g/t gold cut-off for DLO and 0.40 g/t gold for CGO as compared to the December 31, 2010 reserve estimate4 at a 0.15 g/t gold cut-off.
3 The December 31, 2010 resource estimate is set out in the São Vicente Technical Report.
4 The December 31, 2010 reserve estimate is set out in the São Vicente Technical Report.
The increase in the cut-off grade for mineral resources and reserves to 0.25 g/t gold is primarily based on the following two factors: (i) a significant increase in total operating costs since December 31, 2010, including increased labour costs, contractor rates and costs of consumables and the stronger Brazilian real and inflation; and, (ii) a reduction in DLO recovery based on recent column test work. It is important to note that recovery from DLO only represents a small portion of total gold production from the São Vicente Mine, as the majority of gold production comes from the processing of CGO, the recovery of which remains at 80%.
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