- Removal of slimes and ultra-fine particles prior to scrubbing and processing through the Schauenburg pilot plant reduces power requirements and improves recoveries
- The trial resulted in an improved uranium upgrade factor of 7.9, which will now allow the cost effective processing of even lower grade sand
- This breakthrough will increase the size of the available resource that could be economically beneficiated with the Schauenburg process
- The Tubas Red Sand deposit is now being re-interpreted with additional sand intersections from the Tubas Palaeochannel resource to increase the size of the existing 2,217 tonne JORC compliant resource
- A significantly larger sand resource together with the application of this technology could lead to a standalone project
Western Australia’s advanced stage uranium explorer Deep Yellow Limited has revealed that its wholly owned subsidiary Reptile Uranium Namibia (Pty) Ltd (RUN) has made a further breakthrough onthe upgrading of its unique, low grade Tubas Red Sand (TRS) deposit.
Deep Yellow Managing Director Greg Cochran said this was another step towards the potential establishment of the Tubas Red Sand as a standalone project.
“These results mean that we can reduce the cut-off grade of the deposit, thereby increasing the size of the resource. A larger resource, combined with this cost effective beneficiation process, is a major step forward as we continue to search for an opportunity to bring forward the commencement of uranium production from our portfolio of advanced projects in Namibia.”
“We have already re-interpreted the borehole logs from parts of the Tubas Palaeochannel deposit known to contain sand and unconsolidated sediments and Geomine Consulting Namibia is working to provide us with a new JORC compliant resource of this sub-set for the TRS deposit,” he added.
Previous research and pilot plant separation and laboratory screening testwork conducted at RUN’s laboratory facilities using a bulk sample taken from a TRS trenchshowed that the uranium content of the -125 micro m to +20 micro m reject fraction remained remarkablyconstant with varying head grade.
This had the effect of diminishing potential uranium recoveries to the-20 micro m concentrate at lower head grades.
In the quest to improve recovery it was decided to remove the -20 micro m slimes and ultra-fine particles by using a Schauenburg hydrocyclone prior to scrubbing as this is a well-tested effective method of increasing efficiencies and reducing energy requirements.
A low grade TRS trench sample (140 ppm U3O8) was used in the test. After the initial hydrocyclonetreatment the de-slimed underflow (i.e. oversize material) was subsequently scrubbed and manuallyscreened at 125 micro m with the undersize separated again using a Schauenburg hydrocyclone.
The deslimed overflow was combined with the pre-scrubbing overflow and the barren -125 micro m to +20 micro m collected for further testwork to remove the remaining carnotite adhering to the surface of the particles.
This optimised scrubbing method reduced the total mass of uranium remaining in the barren -125 micro m to +20 micro m size fraction to 8.2%, a significant improvement from the initial pilot plant testwork.
Mass pull of the TRS material to the -20 micro m uranium bearing fraction can be highly variable and during this testwork only 10.4% was reported to the -20 micro m size fraction, resulting in an improved uranium concentration upgrade factor of 7.9 compared to the previous 6.9.
These results demonstrate that even lower grade sand-type ores (below 150 ppm U3O8) could potentially be economically beneficiated.
This would allow a reduction in the cut-off grade to around 60 ppm for the TRS deposit which would result in a significant increase in the resource base.
The existing Tubas JORC Resource estimate totals 77.3 Mt at 228 ppm U3O8 for 17,612 tonnes –
U3O8 at a 100 ppm U3O8 cut-off and the TRS JORC Resource estimate totals 13.9 Mt at
160 ppm U3O8 for 2,217 tonnes – U3O8 at a 100 ppm U3O8 cut-off.
Deep Yellow Limited is an advanced stage uranium exploration company with operations in the Namibia and in Australia. In, Australia the company is focused on resource delineation of mid to high grade discoveries in the Mount Isa district in Queensland and also owns the Napperby Uranium Project and exploration tenements in the Northern Territory.