Bannerman Resources has approved an extension of its Etango heap leach demonstration plant program after receiving "excellent" results from the fifth phase of the project in Namibia.
|The heap leach demonstration plant at Etango (Image: Bannerman Resources)
The plant was commissioned in March 2015 to demonstrate the design and projected performance of the Etango uranium project, as well as building knowledge, and to enable the company to pursue value engineering ahead of full production. The five phases completed to date have demonstrated or simulated the heap leaching and solution recycling aspects of the processing route, validating assumptions made in the project's definitive feasibility study (DFS).
The fifth phase, which began in July, aimed to optimise the process parameters by drawing on lessons learned in the preceding phases. Eight columns stacked to five metres in height were operated in an open heap leach circuit to test the impact of different particle sizes, crushing methods and binder addition rates on extraction and acid consumption.
Uranium extraction averaged 93.6%, in line with previous phases, with 90% of uranium extraction occurring over a period of 20-22 days and low acid consumption of 14.4 kg per tonne. As well as providing further confirmation of the definitive feasibility study for Etango, the phase has shown the "clear potential" of processing more coarsely ground material and further optimising reagent use, which could both contribute to further reductions in capital and operating costs.
In light of the findings from phase 5, which had been intended to be the final stage of the demonstration project, Bannerman has announced an extension into a sixth phase to further optimise particle size distribution and establish optimal binder addition. The extra phase is already under way and will be completed by the end of November.
Bannerman CEO Brandon Munro, said the Etango demonstration plant had continued to deliver a "superb" return on investment. "The two-year program has now been extended into a sixth phase, such is the extent of the positive impact on capital and operating costs we expect to attain,” he said.
Etango is in Namibia's Erongo uranium mining region, which hosts the operating Rössing and under-construction Husab mines. Perth, Australia-based Bannerman completed the DFS and environmental and social impact assessment in 2012, and has environmental approvals in place.
Based on the DFS, production is expected to be 7-9 million pounds U3O8 per year (2690-3460 tU) for the first five years and 6-8 million pounds U3O8 per year thereafter over a minimum mine life of 16 years. The project has measured and indicated resources of 57,330 tU at ore grades of up to 0.019%, with inferred resources of 24,630 tU up to 0.16%.
Researched and written
by World Nuclear News