Aura Energy's (ASX: AEE) beneficiation upgrade test results from its Reguibat Project in Mauritania have indicated that more than 80% of mineralisation could be rejected to waste while retaining 89% of the uranium.
This represents a five-fold increase in the grade of the Reguibat deposit to almost 1800 parts per million uranium, with increases of up to 8.5 times in the finer grained samples.
Significantly, one-third of the nine samples tested have fine product uranium grades between 0.27% and 0.34%.
Simple scrubbing and screening tests gave head grades of up to 3000 parts per million uranium, compared with the resource grade of 334 parts per million.
The presence of the uranium mineral, carnotite, in the fine fractions, and the difference in grain size between carnotite and the host rock minerals, explains the positive results to date, also showing potential for even higher grade products by refinement of the size fractioning.
The generation of this high grade product opens opportunities for fast tracked development given the simplicity of the process and potentially significant improvement in project economics.
The mineralisation at Reguibat occurs in single sheets of flat-lying unconsolidated gravels, largely from surface to a depth of 3 to 4 metres, allowing simple and low cost mining.
The current resource at Reguibat contains 49 million pounds uranium at 334 parts per million contained in 70 million tonnes of ore.
Using conventional beneficiation procedures, the project would require a relatively small leaching capacity, and consequently much lower capital and operating costs, given that only 15 million tonnes out of the 70 million tonnes resource will require leaching under this scenario.
The next phase of beneficiation tests will investigate whether further upgrading of the screen product can be achieved by other physical separation techniques, particularly cycloning and ultrafine screening.