African Eagle Resources plc has announced strongly positive metallurgical test work results for its flagship Dutwa Nickel Project in Tanzania, which offer a high potential for improvements to both the Project's capital cost and operating costs.

Following a significant and targeted laboratory metallurgical test campaign on the Wamangola Ferruginous Siliceous ores, the results demonstrate that the FeSi ore is strongly amenable to beneficiation prior to processing and that the beneficiated ore has improved leach characteristics when compared to the run of mine ore. The results exceed the promise identified in the 2011 mineralogical studies, conducted by the Natural History Museum, while also characterizing the significantly improved leach performance of the beneficiated ores, an outcome that is unexpected.

As a result, beneficiation offers the potential to significantly reduce both the operating and capital costs of the Project for the equivalent metal output.

Test work highlights for the Wamangola FeSi ore:
Simple ore beneficiation through low energy scrubbing and water screening results in significant mass rejection of low grade ore material, minimizing the quantity of plant feed necessary to achieve the Project's targeted production output

A significant upgrade is witnessed in ore head grade with up to a 2 times nickel grade improvement from around 1% to around 2%

Leach characteristics of the beneficiated ore are superior to the run of mine ore with:

Reduced acid consumption
Shorter leach times
Reduced residual acid concentrations minimizing neutralization requirements
Strong potential to reduce the throughput capacity of the process plant to achieve the equivalent metal output
Strong potential for a reduction in reagent consumption required to secure optimum metal output

The test work indicates that between one half and two thirds of the FeSi mined run of mine ore will be rejected from the beneficiation process and that the nickel grade of this rejected material will be below economic levels. FeSi ore comprises approximately 70% of the total resource of the Project. Test work is already underway to examine the potential to also beneficiate the Transition ore which comprises most of the rest of the resource.

Strong potential exists to double the Ni grade of the FeSi ore that is fed to the plant from around 1% to 2%. Furthermore, the test work also indicates that the leach response of the beneficiated FeSi ore, compared to the run of mine ore, has improved characteristics in terms of a reduction in acid consumption, reduction in leach residence time and a reduction in the quantity of limestone required for neutralization with the potential consequence of a reduction in operating costs and infrastructure requirements.

Beneficiation Response of Wamangola Ferruginous Siliceous FeSi Ore

Metal Recoveries (and Sulphuric Acid Requirements) for Atmospheric Tank Leaching of Run of Mine and Beneficiated Wamangola FeSi Ores

Metal Recoveries from Beneficiated Wamangola FeSi Ore obtained by Atmospheric Leaching with Acid Addition of 515 kg H2SO4 /t Beneficiation Product (Leach Feed)

Metal Recoveries from Beneficiated Wamangola FeSi Ore obtained by Atmospheric Leaching with Acid Addition of 645 kg H2SO4 /t Beneficiation Product (Leach Feed)

Mr Trevor Moss CEO of African Eagle said that "We are very excited about these metallurgical results which exceed our expectations in all aspects. They confirm the unusual and positive nature of the Dutwa mineralization and demonstrate both the necessity and benefits of doing extensive and detailed metallurgical test work at this stage of the feasibility study."

He added that "The potential of beneficiating the FeSi ore was highlighted in the NHM report but these results both exceed our expectations and extend them to highlight positive leach performance that was not previously identified. Beneficiation prior to processing on a commercial scale will significantly reduce the amount of ore we need to process through the hydrometallurgical plant by greater than 50%, whilst almost doubling the nickel head grade with the potential for this to approach 2% for a significant period of the life of the operation. The improved leach behavior of the beneficiated ore results in a smaller plant, which requires less acid and reagents while maintaining metal output. This has the potential to significantly improve the overall Project economics by reducing both the capital expenditure and the operating costs."

Mr Trevor Moss said that "In order to fully capitalize on this strongly positive data we need to expand our metallurgical test program through additional testing and to fully incorporate these results to the pit optimization and mine scheduling and into the process model and flow sheet to ensure the pilot plant is configured appropriately. Therefore, we have decided the most prudent step is to adjust the scheduling of the pilot plant campaign and to optimize our available funds. We need to be confident that the pilot plant is properly configured and representative of the commercial scale plant we will build ahead of embarking on this significant program. The potential capital cost and operating cost savings on the Project are substantial."

Source - African Eagle Resources plc

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