This Preliminary Economic Assessment describes the processing facilities and recovery methods designed to produce yellowcake from uranium-bearing lixiviant at the Dewey Burdock in-situ recovery project in South Dakota.
The 2025 Preliminary Economic Assessment for the Dewey Burdock uranium project outlines a central processing plant (CPP) located on the Burdock property and a satellite facility at Dewey. The two facilities are separated by approximately four miles, and loaded resin is transferred between them by truck. The processing circuits recover uranium from pregnant lixiviant solution through ion exchange, elution, precipitation, dewatering, drying, and packaging. The CPP houses the complete processing flow sheet, while the satellite contains an ion exchange circuit and a resin transfer system.
The process begins with the recovery of uranium from pregnant lixiviant using an ion exchange circuit. Each IX vessel is designed to contain a 500 cubic foot batch of anionic ion exchange resin. Vessels are configured in parallel trains of multiple columns operating in series, using a pressurized downflow methodology for loading. Production booster pumps are located upstream of the IX trains, and injection booster pumps are located downstream. An interior stainless steel piping manifold distributes lixiviant evenly across the resin bed. Dissolved uranium adsorbs onto the resin, and the resultant barren lixiviant exits the vessels with less than 2 ppm uranium before being returned to the wellfield where oxygen and carbon dioxide are added prior to reinjection.
A production bleed is drawn from the injection stream prior to reinjection into the wellfield to maintain control of hydraulic conditions in the production zone. This bleed is directed to a smaller bleed column where residual uranium is collected. The barren bleed is discharged at a constant flow rate to the radium treatment system before entering settling ponds designed for a minimum of 13 days residence time. Water from the settling ponds is tested periodically to confirm conformance with discharge standards and then disposed of via deep disposal wells.
Critical Data
| Parameter | Value | Unit | Notes |
|---|---|---|---|
| Production flow rate | 4,000 | gpm | Basis for water balance |
| Bleed rate | 40 | gpm | 1% of production flow |
| IX resin batch | 500 | ft³ | Per vessel |
| Barren lixiviant uranium | <2 | ppm | After IX loading |
| Settling pond residence | ≥13 | days | Minimum design |
| Fresh water supply rate | 1.9 | gpm | From Madison formation |
| CPP make-up and washdown | 12 | gpm | Approximate |
| Restoration RO feed | 250 | gpm | During restoration |
| Restoration RO permeate return | 175 | gpm | Returned to wellfield |
| Restoration RO concentrate | 75 | gpm | To liquid effluent management |
| Propane for drying | 1 | MBTUH | One dryer, 12 hours per day |
| Propane for heating | 3.9 | MBTUH | CPP and Satellite, winter months |
| Electricity | 12 | million kWh/yr | CPP and wellfields, peak production |
| Dryer temperature | <300 | °F | Low temperature vacuum dryer |
| Fresh water makeup | 1.9 | gpm | Madison formation well |
| Deep injection wells | 4 | wells | UIC Class V, draft permit contested |
| Deep injection wells installed | 2 | wells | After final approval |
| Product packaging | 55 | gallon | Steel drums |
Overview
The Dewey Burdock project is an in-situ recovery uranium development in the planning stage. The processing scheme is built around ion exchange technology to recover uranium from a pregnant lixiviant solution. The design differentiates between the CPP and satellite functions, with the satellite dedicated to IX loading and resin transfer while the CPP contains the full elution, precipitation, and product finishing circuits. The water balance is based on a production flow rate of 4,000 gpm with a 1% bleed for hydraulic control. Liquid waste disposal is planned through Class V deep injection wells, for which a permit application has been submitted to the EPA and a draft permit issued, though the permit is currently in contestation. Land application is noted as an option but is not included in this PEA.
Key Process Stages
The processing flow sheet follows a sequential series of stages from pregnant lixiviant through to packaged yellowcake. The IX circuit is the primary recovery step, followed by elution, precipitation, and product finishing. Water management and waste disposal are treated as integral process requirements, with specific design criteria for bleed handling and restoration activities.
Ion exchange recovers uranium from the pregnant lixiviant. The IX circuit uses anionic resin in parallel trains of multiple columns operating in series. The vessels are designed to optimize contact time between pregnant lixiviant and resin. The barren lixiviant is returned to the wellfield with less than 2 ppm uranium after oxygen and carbon dioxide are added. The loaded resin transfers to the elution circuit, where a brine solution strips the uranium, and the eluted resin is rinsed and returned to the IX vessels.
The elution circuit uses a sodium chloride and sodium carbonate brine solution to strip uranium from the loaded resin, producing a uranium-rich eluate. The precipitation circuit then adjusts the pH with sulfuric acid to bring the eluate to a pH range of 2 to 3, which breaks down uranyl carbonate and liberates carbon dioxide. Sodium hydroxide raises the pH to 4 to 5, after which hydrogen peroxide is added in a batch process to form an insoluble uranyl peroxide compound. The pH is then raised to approximately 7, and the slurry pumps to a thickener where uranium settles and gravity-thickens into a yellowcake slurry. The uranium-depleted supernate overflows the thickener and is disposed of via a deep injection well after treatment to remove radium and other radionuclides.
Product filtering, drying, and packaging complete the processing circuit. Yellowcake from the thickener underflow is washed to remove excess chlorides and other soluble contaminants. The slurry is dewatered in a filter press, and the filter cake transfers in an enclosed conveyor directly to a low-temperature vacuum dryer. The dryer operates at less than 300°F and is heated by circulating thermal fluid through an external jacket. Off-gases, primarily water vapor, are filtered through a bag house to remove entrained particulates and then condensed. Compared with conventional high-temperature drying using multi-hearth systems, this dryer produces no significant airborne particulate emissions. The dried yellowcake is packaged into 55-gallon steel drums for storage before transport by a licensed trucking contractor to a conversion facility. The drying and packaging stations are segregated within the processing plant for worker safety, with dust abatement and filtration equipment deployed in this area. Filled drums are staged in a dedicated and locked storage until transport.
Solid waste disposal follows classification-based segregation. Non-contaminated waste is disposed of at the nearest permitted sanitary waste disposal facility. Hazardous non-radiological waste is segregated and sent to the nearest permitted hazardous waste facility. Radiologically contaminated solid wastes that cannot be decontaminated are classified as 11.e.(2) byproduct material, and are packaged and stored on site temporarily, then periodically shipped to a licensed 11.e.(2) byproduct waste facility or a licensed mill tailings facility.
Additional Interesting Data and Summary
The water balance includes a production flow rate of 4,000 gpm with a bleed of 40 gpm (1%) to maintain hydraulic control of the mine units. Make-up water for the CPP is supplied from a local fresh water supply well at approximately 12 gpm for process make-up and washdown. Restoration activities include a 250 gpm feed to reverse osmosis, with 175 gpm returned to the wellfield and 75 gpm directed to a liquid effluent management system using lined impoundments and treated water injection into permitted Class V injection wells. Fresh water from a Madison formation well is estimated at 1.9 gpm to meet demand, and a Madison well provides make-up water to minimize wellfield drawdown if necessary.
Liquid waste disposal options include deep well injection and land application. The PEA does not include land application, relying on two Class V wells permitted under EPA, with two additional wells possible if new or additional disposal capacity is needed. In the case of land application, the bleed stream would be treated with ion exchange to remove residual uranium followed by barium chloride treatment to remove radium, with sludge separation achieved in a radium settling pond. Reagent tanks for radium removal are located within the CPP and satellite. Liquid waste will be injected and isolated from any underground source of drinking water. The EPA has issued a draft permit, though it is currently in contestation. Upon final approval, enCore plans to install two wells, one at the CPP and one at the satellite.
Energy requirements are estimated at nearly 12 million kWh annually of electricity to operate the CPP and wellfields during peak production with simultaneous mining and restoration activities. Approximately 3.9 MBTUH of propane is required to heat the CPP and satellite during winter months, and approximately 1 MBTUH of propane is consumed to operate one dryer for 12 hours per day.
Key Processes
- Ion exchange: anionic resin in parallel trains, pressurized downflow loading
- Elution: sodium chloride and sodium carbonate brine strip, uranium-rich eluate
- Precipitation: sulfuric acid acidification, sodium hydroxide pH adjustment, hydrogen peroxide batch precipitation, pH raised to approximately 7
- Thickening: gravity settling of uranyl peroxide precipitate
- Filtration: filter press dewatering, enclosed conveyor
- Drying: low-temperature vacuum dryer at less than 300°F, thermal fluid heating, bag house off-gas filtration
- Packaging: 55-gallon steel drums, dedicated storage
- Bleed management: 40 gpm bleed, radium treatment, settling ponds, deep injection
- Water treatment: reverse osmosis for restoration, barium chloride radium removal, Class V injection
Source: Dewey Burdock PEA , 2025 Technical Report, January 2025. Project website: enCore Uranium Dewey Burdock project
Note on the report: The report states that land application has not been included in this PEA, but it also describes land application as an option for disposing of liquid waste generated during production and restoration.
Project website: Dewey Burdock PEA, 2025 Technical Report
Consolidated report summaries
The following former standalone pages about this operation were consolidated here on October 25, 2026. They are retained for source traceability; dates and figures reflect each report’s own effective date and may be superseded by the current information above.
Dewey-Burdock PEA Update — 2012 Technical Report
This 2012 Preliminary Economic Assessment technical report update describes the conceptual design for a uranium in-situ leach project with a central processing plant and satellite ion-exchange facility planned for a nine-year mine life at a production rate of 1 million pounds per year.
The Dewey-Burdock uranium project, located in South Dakota, is planned as an in-situ leach (ISR) operation that would use a central processing plant at the Burdock site and a satellite facility at the Dewey site, located approximately 4 miles apart. This 2012 technical report update presents a Preliminary Economic Assessment (PEA) that provides a conceptual design for the processing facilities, including sizing of major equipment, a mass balance for the uranium recovery circuits, a water balance, and an estimate of the full-time workforce required for operation. According to SRK Consulting, which prepared the report, the proposed facility and process design are essentially industry standard for ISR uranium recovery.
The project assumes an annual operating schedule of 350 days, 24 hours per day, with daily production required of 2,857 lb of U3O8. The design basis includes a head grade of 60 ppm uranium from the well field, with an ultimate uranium extraction of 75% assumed during well field operation. The report notes that this recovery value is an estimate based on similar existing operations in Powertech's experience profile. SRK recommends acceptance of the 75% recovery assumption for this Preliminary Assessment. The plant design includes an IX process line at the central processing plant, with loaded resin trucked from the satellite facility to the central plant for elution, precipitation, product washing, filtering, drying, and packaging.
Critical Data
| Parameter | Value | Unit | Notes |
|---|---|---|---|
| Indicated resources | Not stated | lb U3O8 | Referenced as 1,000,000 in table context for annual production |
| Mine life | 9 | yr | Based on current potentially mineable resource studies |
| Daily operating schedule | 24 | h/d | Not stated |
| Annual operating schedule | 350 | d/yr | Not stated |
| Daily production required | 2,857 | lb U3O8/d | Not stated |
| Annual yellowcake production | 1,000,000 | lb U3O8/yr | Not stated |
| IX feed flow rate (Burdock) | 2,400 | gpm | Not stated |
| IX feed flow rate (Dewey) | 1,600 | gpm | Not stated |
| IX feed flow rate (Total) | 4,000 | gpm | Not stated |
| Head grade from well field to IX | 0.060 | g/L | 60 ppm |
| Barren solution grade | 0.002 | g/L | Not stated |
| Total recovery in IX columns | 97 | % | Not stated |
| Dried yellowcake mass flow | 121 | lb/h | Not stated |
| Dried yellowcake solids | 99.0 | % | Not stated |
| Daily yellowcake production | 2,875 | lb/d | Predicted from mass balance |
| Filter cake solids | 40.7 | % | In precipitation feed |
| Resin volume per IX vessel | 500 | ft³ | Fixed diameter 12 ft |
| Thickener diameter | 30 | ft | Additional storage capacity required |
| Filter press size | 65 | ft³ | Quotes obtained |
| Mobile equipment lease period | 5 | yr | Not stated |
| Workforce (full operation) | 84 | staff | Central and satellite facilities |
| Aquifer feed | 120 | gpm | Production well field |
| Aquifer feed | 52 | gpm | Drilling, roads, etc. |
| Recycle | 3,880 | gpm | From process |
| Total from aquifer | 336 | gpm | Not stated |
| Total to deep disposal well | 127 | gpm | Not stated |
| Resin haul per day | 9 | t | ISR daily yield |
| Truck design | 25 | t | Tandem axle, dual wheel |
| Drying temperature | <300 | °F | Low temperature vacuum dryer |
| Drying batch time | 16 | h | Typical for uranium applications |
| Yellowcake transport | 55 | gal | Steel drums |
| Yellowcake shipments | 295 | Not applicable | Over life of mine |
| Uranium peroxide dried | 3,300 | lb/d | For 1,000,000 lb/yr U3O8 |
| Sludge classification | Not stated | Not stated | 11(e) (2) byproduct material |
| Main floor slab thickness | 12 | in | Double steel reinforcing |
| Deep disposal well injection | Not stated | Not stated | Both formations suitable per preliminary studies |
| Liquid waste disposal method | Not stated | Not stated | Deep well injection with reverse osmosis considered in economic analysis |
| Process water source | Not stated | Not stated | Local aquifer water |
Overview
The Dewey-Burdock project is planned as an in-situ leach uranium recovery operation. The processing design consists of a Central Processing Plant (CPP) at the Burdock site and a Satellite Facility at the Dewey site, with a distance of approximately 4 miles between the two facilities. The conceptual design criteria, summarized in Table 14.1 of the report, provide the basis for the economic analysis. Key parameters include a nine-year mine life, 24-hour daily operation, 350 operating days per year, and daily production of 2,857 lb of U3O8. The average uranium concentration in the well field feed for this design is 60 ppm. SRK Consulting made formatting changes to fit this report, and the report includes SRK comments and opinions where present.
The IX loading vessels are capable of processing 3,000 gpm of 60 ppm lixiviant. The elution, precipitation, product washing/filtering, drying, and packaging circuits are designed to process more than 2,857 lb U3O8 per day, equivalent to 1 million lb per year. The IX vessels were sized using a fixed diameter of 12 ft and a resin volume of 500 ft³. Trucks will transfer resin between the Satellite Facility and the Central Processing Plant. The estimated full-time staff for the Dewey-Burdock project during full operation of the Central Processing Facility, Satellite Facility, and all associated well fields is 84 staff.
Key Process Stages
The recovery of uranium by ion exchange involves the following process circuits, each described in detail in the technical report:
Resin Loading. The Burdock CPP resin loading circuit processes lixiviant from the well field, with a head grade of 60 ppm uranium. The loading vessels have a capacity of 3,000 gpm of 60 ppm lixiviant. The IX columns achieve a predicted total recovery of 97%, with a barren solution grade of 0.002 g/L.
Production Bleed. A production bleed circuit is part of the IX process, though specific details for the bleed stream are not provided in the report.
Resin Elution. The elution process consists of four stages. Three eluant stages contact one 500 ft³ batch of resin with four bed volumes of eluant each, and one rinse stage contacts the batch with four bed volumes of fresh water. Loaded resin is transported by truck from the Dewey satellite facility to the Burdock central processing plant.
Precipitation. The uranium-depleted supernate solution overflows the thickener and is processed further. The report indicates a 30 ft diameter thickener was selected for the project, providing additional storage capacity for yellowcake slurry. The precipitation circuit produces a slurry that is fed to a filter press.
Product Washing, Drying, and Packaging. The slurry is dewatered in a filter press, with the filter cake transferred by enclosed conveyor directly to the yellowcake dryer. Quotes were obtained for 65 ft³ sized filter presses. The yellowcake is dried in a low temperature (<300°F) vacuum dryer. These are batch dryers that typically take 16 hours to process a batch in uranium applications, with one batch equal to one day of production of yellowcake. For instance, production of 1,000,000 lb/yr of U3O8 will require drying of approximately 3,300 lb/d of uranium peroxide (UO4·2H2O) product.
Additional Interesting Data and Summary
The project includes a radium settling pond system at the central processing plant where radium will be precipitated. The resulting sludge is classified as an 11(e)(2) byproduct material. For liquid waste disposal, Powertech retained Petrotek Engineering Corp., with preliminary studies indicating that two formations are suitable for injection of wastewater. Deep well disposal with reverse osmosis was the wastewater disposal option investigated, and only deep well injection was considered in the economic analysis. Powertech is also investigating land application of treated water as a disposal method. The total flow to the deep disposal well is predicted to be 127 gpm.
Solid waste disposal at the ISR facility will include spent resin, empty packaging, tank sediments, and other materials that will be reviewed and entered into waste stream classifications on site. Non-contaminated waste will be disposed of at the nearest permitted sanitary waste disposal facility. The main floor slab in the central processing plant is designed at 12 in thick with double steel reinforcing, based on AASHTO design Tandem Load Vehicle with 25 kip load on each axle. The floor covering requires a special epoxy blend that needs slab preparation and several layers. Soil conditions are unknown.
Yellowcake will be transported in 55 gal steel drums following standard industry protocols, with approximately 295 shipments estimated over the life of the mine based on the present resource estimate. Major mobile equipment will include resin haul trucks, and several pieces of heavy equipment for excavation of mud pits, road maintenance, and reclamation activities. Powertech will lease mobile equipment for a 5-year period. Dedicated maintenance facilities will be constructed along with the central processing plant; the most commonly overhauled equipment will be the submersible pumps utilized on the recovery wells. A single source of process water is planned: local aquifer water. Staff schedules will vary based upon duty.
The predicted mass balance results indicate that the proposed flow rates and recoveries will produce the target daily yellowcake production. The conceptual design criteria and mass balance results were independently spot checked by Lyntek using data from the Design Criteria.
Key Processes
- In-situ leach (ISR) mining with well field
- Ion exchange (IX) resin loading at satellite and central facilities
- Resin transport by truck between sites (approximately 4 miles)
- Production bleed circuit
- Four-stage resin elution (three eluant stages plus one rinse stage)
- Uranium precipitation with thickener (30 ft diameter)
- Filter press dewatering (65 ft³ filter presses)
- Low temperature (<300°F) vacuum drying of yellowcake
- Product washing, packaging, and transport in 55 gal steel drums
- Radium removal via settling pond and precipitation
- Deep well disposal of wastewater
- Solid waste classification and disposal
Source: Dewey-Burdock PEA Update , 2012 Technical Report, 2012. Project website: Powertech Uranium Corp. (https://www.federalregister.gov/documents/2025/12/19/2025-23415/powertech-usa-inc-dewey-burdock-in-situ-uranium-recovery-project-draft-programmatic-agreemen)
Project website: Dewey-Burdock PEA Update, 2012 Technical Report
