Name of the Project
Tiris uranium project.

Location
Sahara Desert, north-east Mauritania.

Project Owner/s
The project is owned by Tiris Resources (85%), a subsidiary of Aura Energy, and the Mauritanian government, through its agency Societe Mauritanienne des Hydrocarbons et de Patrimone Minier (15%).

Project Description
Tiris is the first major calcrete uranium discovery in the region.

A definitive feasibility study (DFS) has confirmed the uranium project as a low capital- and operating-cost development opportunity.

Average uranium oxide production is estimated at 823 000 lb, with life-of-mine (LoM) production estimated at 12.35-million pounds of uranium oxide.

The beneficiation plant ore-throughput rate is estimated at 1.25-million tonnes a year and that of the process plant at 160 000 t/y.

The LoM has been estimated at 15 years.

Potential Job Creation
Not stated.

Net Present Value/Internal Rate of Return
The project has an after-tax net present value, including royalties and tax, at an 8% discount rate, of $89.9-million and an internal rate of return of 26%, including royalties and tax, with a project payback from startup of 3.25 years.

Capital Expenditure
An updated capital cost estimate for project has increased the projected cost by 10.4%.

The project is expected to require a capital investment of $74.8-million, compared with the $62.9-million estimated in the 2019 DFS.

Planned Start/End Date
Not stated.

Latest Developments
Aura Energy has achieved an average 550% increase in uranium grade through pilot-scale confirmatory results from simple screening techniques conducted at the Tiris project.

Preliminary bulk leaching tests have also confirmed rapid uranium extraction of more than 95%.

The company has said the substantially positive upgradability of the Tiris uranium mineralisation is a key differentiator between Tiris and other uranium projects with comparable feed grades; this results in a smaller, more efficient leach circuit with generally lower capital and operating costs.  

Aura initiated a programme of testwork with minerals processing consultancy ANSTO Minerals in January this year to confirm process design inputs for Tiris. The ongoing programme is using Tiris sample concentrates generated from the beneficiation pilot plant trial.

The test programme is expected to be completed in the third quarter.

The focus of the programme is to confirm design criteria for use in the planned front-end engineering design (FEED) study as Aura advances towards a final investment decision for the Tiris project.

Incoming positive results continue to drive Aura towards the consideration of such a decision, which is targeted for the first quarter of next year.

Key testwork steps include bulk leaching tests to confirm optimum reagent dosage and consumption and demonstrate optimum leach residence time to achieve maximum uranium recovery. This will be followed by ion-exchange optimisation tests and modelling to demonstrate uranium recovery from leach liquor and concentration prior to precipitation, as well as uranium precipitation tests to produce yellowcake product samples for marketing.

The next steps will be to use leach solution generated from the bulk leach tests to complete optimisation and modelling for the uranium ion-exchange circuit. This will then flow into precipitation optimisation testwork, which will result in using final yellowcake product samples to support uranium marketing discussions with end-users, including nuclear utilities.

In addition to the confirmation and optimisation of the process parameters for uranium, testwork will be performed on the extraction and recovery of vanadium pentoxide as a by-product.

Vanadium occurs with the host uranium mineral, carnotite, in the Tiris resources. During the leaching of uranium, the vanadium is also extracted and can be recovered in the ion-exchange circuit separately from uranium and, subsequently, precipitated and calcined to produce vanadium pentoxide flake by-product. The by-product credit is anticipated to result in a reduction in overall operating costs for uranium production.

The vanadium by-product test work programme will include the examination of two alternative options for the separation of vanadium from uranium in the ion-exchange circuit.

The results will be announced when they are available.

Key Contracts, Suppliers and Consultants
Minecore (engineering consultant); Simulus Group (leaching/ion-exchange engineering consultant); Adelaide Control Engineering (uranium-processing engineering consultant); Mining Plus (mine design consultant); General Studies and Achievements in Africa (geotechnical consultant): PhotoSat (satellite surveying); H&S Consultants (resource estimation); 3D Exploration (grade determination by gamma logging); Poseidon Geophysics (downhole gamma logging); Australian Nuclear Science & Technology Organisation (metallurgical testwork, steady-state simulation, uranium disequilibrium); Australian MinMet Metallurgical Laboratories (metallurgical testwork); CSIRO Minerals, University of South Australia, Pontifex Associates (mineralogy); Activation Laboratories (uranium determination); Geoterra (hydrogeological consulting); SES (water geophysics); ALS Global (chemical analysis); Wallis Drilling (air-core drilling); Capital Drilling (diamond drilling); Earth Systems (environmental- and social impact assessment consultants); METS Engineering (operating cost review); Golders Associates (groundwater supply review); ANSTO Minerals (bulk metallurgical testwork); and Mintek (pilot-scale tests).

Contact Details for Project Information
Aura Energy, tel +61 3 9516 6500 or email info@auraenergy.com.au.