This feasibility study presents a proposed uranium processing plant design for the Arrow deposit at the Rook I Project in Saskatchewan.
Report context
This NI 43-101 Technical Report on the Arrow Deposit, Rook I Project in Saskatchewan presents the results of a feasibility study completed in February 2021. The report documents proposed process plant design, mine infrastructure, capital and operating cost estimates, and economic analysis for the project. The study was prepared by Stantec Consulting Ltd., Wood Canada Ltd., RPA (now part of SLR Consulting Ltd.), and Golder Associates. The effective date of the Mineral Resource estimate is February 2021. The project is located in northern Saskatchewan and is based on the Arrow uranium deposit.
Processing route
Ore sorting and grinding
The process plant design is based on metallurgical testing and on unit processes successfully used in uranium process plants across the world, including plants in northern Saskatchewan. The proposed plant will include ore sorting and grinding as initial steps. Plant throughput is designed at 1,300 t/d with design production of 30 million pounds U₃O₈ per annum. A 3-month ramp-up period is expected to reach design throughput.
Leaching and liquid-solid separation
Following grinding, the process includes leaching, then liquid-solid separation via counter current decantation and clarification.
Solvent extraction and precipitation
The process continues with solvent extraction (SX), followed by gypsum precipitation and washing, then yellowcake (YC) precipitation and washing, and finally YC drying, calcining and packaging.
Tailings preparation and effluent treatment
The design of tailings preparation has been improved to facilitate a more reliable tailings deposition strategy through the paste plant. The process plant includes tailings preparation and paste tailings plant, and effluent treatment.
Water supply and reagent requirements
Water from the settling pond and fresh water from Patterson Lake will be fed to the process plant. The amount of water recycled from the settling pond has been further optimized to reduce fresh water requirements by using settling pond water for counter current decantation (CCD) wash water and using belt filter filtrate for paste process water.
Major reagents required will include sulphur, sulphuric acid, unslaked lime, hydrogen peroxide, flocculant, kerosene, tertiary amine, isodecanol, sodium carbonate, magnesia, barium chloride and ferric sulphate.
Power requirements
The process plant will require approximately 7.4 megawatts (MW) of power to operate at full capacity. The paste plant will require approximately 0.9 MW of power.
Ore and special waste stockpiles
There will be an ore stockpile consisting of four piles of differing grades, each approximately 6,500 m³. It is estimated that about 1% of waste rock brought to surface will be mineralized but below economic grade, and this material is stored in a special waste rock stockpile area with an anticipated volume of 60,000 m³. The special waste will be processed during normal operations to ensure the mill head grade remains below the 5% U₃O₈ design limit, with remaining special waste processed at end of mine life. Both ore and special waste stockpiles will be dual lined with high-density polyethylene (HDPE) and designed as self-contained facilities capable of holding a full probable maximum precipitation (PMP) 24-hour event.
Process plant optimizations proposed
The report recommends further studies including: loaded strip acid recovery, gypsum belt filter optimization, YC particle size enhancement, YC belt filter optimization, clarifier optimization, paste plant optimization, geo-metallurgical characterization, and mine water pre-treatment technology. The total estimated cost for this program is $1.0–1.5 million.
Key reported parameters
| Parameter | Units | Value | Basis |
|---|---|---|---|
| Plant throughput | t/d | 1,300 | Proposed design |
| Design production | Mlb U₃O₈/a | 30 | Proposed design |
| Process plant power requirement | MW | 7.4 | Proposed design |
| Paste plant power requirement | MW | 0.9 | Proposed design |
| Mill head grade design limit | % U₃O₈ | 5 | Design parameter |
| LNG power plant requirement | MW | 26.5 | Proposed design |
| Nominal power demand | MW | 24.1 | Design basis |
| Ore stockpile pile volume | m³ | 6,500 each (four piles) | Proposed design |
| Special waste stockpile volume | m³ | 60,000 | Proposed design |
| Total waste rock LOM | Mm³ | 5.9 | Estimate |
| PAG waste rock | Mm³ | 4.6 (78%) | Estimate |
| NPAG waste rock | Mm³ | 1.3 | Estimate |
| Ramp-up period | months | 3 | Expected |
| Capital estimate classification | , | AACE Class 3 | Estimate |
| Capital estimate accuracy | , | ±15% | Intended |
| Pre-tax NPV at 8% | $ million | 5,577 | Economic analysis |
| Pre-tax IRR | % | 64.9 | Economic analysis |
| Pre-tax payback period | years | 0.8 | Economic analysis |
| Post-tax NPV at 8% | $ million | 3,465 | Economic analysis |
| Post-tax IRR | % | 52.4 | Economic analysis |
| Post-tax payback period | years | 0.9 | Economic analysis |
| Uranium price assumption | US$/lb U₃O₈ | 50 | Financial analysis |
| Exchange rate assumption | C$:US$ | 0.75 | Financial analysis |
| Discount rate base case | % | 8 | Economic analysis |
Technical qualifications
Development and licensing approvals are not currently in place, and statutory permits, including environmental permits, are required to be granted prior to mine commencement. The environmental assessment (EA) process for the Rook I Project is in progress as of the effective date of this report, and no recommendations from the EA or licensing processes for future monitoring and/or management of environmental and social aspects have been determined. Contracts have currently not been entered into for the project. The capital cost estimate meets the classification standard for a Class 3 estimate with intended accuracy of ±15%, reported in Q4 2020 Canadian dollars. The report notes that if additional mining, technical, and engineering studies are conducted, these may alter the project assumptions and may result in changes to calendar timelines and information contained in the report.
*Source: Arrow Deposit, Rook I Project, Saskatchewan, NI 43-101 Technical Report on Feasibility Study, February 2021, Sections 1.0 (Summary) and 2.0 (Introduction).*
