Name of the Project
Mulga Rock uranium project.

Location
The project is located east-north-east of the regional mining city of Kalgoorlie-Boulder, in the Shire of Menzies, in Australia.

Client
Vimy Resources.

Project Description
The Mulga project is the largest advanced uranium project in Australia. It comprises two separate mining areas over a total length of 30 km, with the individual deposits ranging in length from 1 km to 8 km.

The Mulga Rock East mining centre comprises the Ambassador and Princess deposits and the Mulga Rock West mining centre comprises the Shogun and Emperor deposits. The project has an ore reserve of 22.7-million tonnes at 845 parts per million (ppm) triuranium octoxide (U₃O₈) for 42.3-million pounds of U₃O₈. The project has a total resource estimate of 71.2-million tonnes at 570 parts per million (ppm) U₃O₈ for a contained 90.1-million pounds of U₃O₈.

The definitive feasibility study (DFS) is based on a low-risk, large-scale openpit mining operation that will underpin production of 3.35-million pounds of U₃O₈ a year over a projected 15-year mine life, with an estimated total production of 47.1-million pounds of U₃O₈.

The DFS proposes to use large-scale openpit ‘strip’ mining techniques like those used in mineral sands and other bulk mining operations. Strip mining starts with the excavation of an initial boxcut to expose the ore, with the overburden placed in a surface landform. After mining the ore exposed by the first boxcut, the resulting pit void will be able to take the overburden from the next mining strip as mining moves along strike. In general, mining advances one strip at a time, with previously mined areas progressively backfilled and rehabilitated.

The mine schedule proposes that the Ambassador North pit be mined first, prior to the start of uranium production, with ore stockpiled within the ultimate Ambassador pit footprint and adjacent to the process plant. This will create a sterilised pit void to allow for process tailings to be discharged into an inpit tailings storage facility at the start of uranium production. The formal start of operations is defined by first ore being processed through the semiautogenous (SAG) mill in Year 1, Month 1.

At the completion of the Ambassador North pit, mining will start at Ambassador West targeting high-grade ore zones for direct feed to the SAG mill at the process plant. Two conventional truck-and-shovel pits will be mined at Ambassador West from Year 0 to Year 2, with a third high-grade pit being mined at Ambassador East from Year 1 to Year 3.

Ore that is not directly fed into the SAG mill from the high-grade pits will be stockpiled according to predetermined cutoff grades in front of the process plant. Only the high-grade and midgrade stockpiles will be used to manage the ore feed into the SAG mill during the initial high-grade production ramp-up period. High-grade ore will be maintained from the pits and stockpiles until Year 2, Month 8.

The beneficiation plant will start operation in Year 2, Month 9. Ore will be reclaimed from all available run-of-mine stockpiles until Year 4, Month 7, when stockpiles will be exhausted. Mining will continue at Ambassador East from the void of the high-grade starter pit and then along strike using the strip mining method until Year 7.
Depending on uranium grade, ore will be supplemented from the Princess deposit between years 3 and 6. Strip mining will start at Ambassador West during Year 6, with operations continuing until Year 14.

The ore from Ambassador West will be blended throughout this time, with ore being sourced from Ambassador South, Shogun and Emperor. Ambassador South will start in Year 7 and continue until Year 10, while Shogun and Emperor will start in years 9 and 11 respectively, and continue to the end of the mine’s life in Year 15. Ore from Shogun and Emperor will be hauled to the beneficiation plant using B-double side tippers along a dedicated haul road within the restricted area of the mine.

The processing facility will comprise four main sections, separated by surge tanks between the respective sections in the process flowsheet – ore beneficiation, a uranium extraction circuit (leach resin-in-pulp elution), ultrafiltration/nanofiltration and a uranium precipitation circuit.

The plant will have a throughput of 2.4-million tonnes a year.

Potential Job Creation
Not stated.

Net Present Value/Internal Rate of Return
The project has a net present value, at an 8% discount rate, of A$530-millon and an internal rate of return of 25%, with a payback of 3.1 years.

Value
The capital cost of the project is estimated at A$493-million, including $41.7-million in contingencies.

Duration
First production is targeted for 2021.

Latest Developments
None stated.

Key Contracts and Suppliers
None stated.

On Budget and on Time?
Not stated.

Contact Details for Project Information
Vimy Resources, tel +61 8 9389 2700, fax +61 8 9389 2722 or email info@vimyresources.com.au.