Matamec Explorations' October 2013 feasibility study for the Kipawa rare earth project in Québec designs a 3,650 t/d plant producing 600,050 t a year of mineral concentrate for an on-site sulfuric acid leach and solvent extraction circuit.
The Feasibility Study for the Kipawa Project, issued on October 17, 2013, was prepared by Roche-Genivar and others for Matamec Explorations Inc. The design draws on information from Matamec, previous studies, testwork at SGS Mineral Services Lakefield and Pocock and by equipment suppliers, Roche-Genivar's own calculations, and advice from sub-consultants such as SimSAGe. The plant is sized for 1,332,250 t a year of run-of-mine ore at 3,650 t/d and 91% availability, operating 24 hours a day, 365 days a year. The mass and water balance is based on an average diluted rare earth oxide grade of 0.4105%.
Critical Data
| Parameter | Value | Unit | Notes |
|---|---|---|---|
| Report issue date | October 17, 2013 | Not applicable | Feasibility study for Matamec Explorations Inc. |
| ROM processing rate | 1,332,250 t/a (3,650 t/d, 167.2 t/h) | Not applicable | 91% plant availability |
| Average feed grade | 0.4105 | % REO (diluted) | Mass balance basis |
| Crusher availability | 50 | % | Open-circuit primary and secondary crushing |
| Fines weight recovery | 10.2 | % | Grinding cyclone slimes to concentrate |
| Magnetic concentrate weight recovery | 34.8 | % | High-intensity magnetic product |
| Overall concentrate weight recovery | 45.0 | % | 600,050 t/a to hydrometallurgy |
| Magnetic separation tailings | 899,945 | t/a | To the MagSep tailings facility |
| Hydrometallurgical plant availability | 91 | % | Not applicable |
| Products | Heavy and light rare earth products | Not applicable | From solvent extraction |
Overview
Based on bench, pilot and variability testwork, the report states the process is suitable for ore from across the whole deposit over the mine life. It has three parts. Mineral processing concentrates the rare earth minerals by grinding, desliming and magnetic separation. A hydrometallurgical plant leaches the concentrate with sulfuric acid and precipitates a rare earth carbonate. A purification plant separates the carbonate into heavy and light rare earth products by solvent extraction.
The beneficiation balance shows how the concentrate is built. Grinding cyclone slimes, 10.2% of the feed, go straight to concentrate. Low-intensity magnetic separation removes magnetite to rejects. High-intensity magnetic separation recovers 34.8% of the feed as magnetic concentrate and rejects 42.0% as non-magnetic tails. In total, 45.0% of the feed reports to the hydrometallurgical plant.
Key Process Stages
Crushing. Trucks from the open pit tip into a primary crushing shelter with a rock breaker, grizzly, dump hopper, apron feeder and roll crusher. A conveyor fitted with a metal detector and magnet carries the ore to a secondary area with a screen, surge hopper, vibrating feeder and cone crusher. Both areas are in insulated fabric shelters with dust collection, and the circuit runs in open loop.
Grinding and desliming. Crushed ore is ground and classified. The fine slimes from the grinding cyclones report directly to the concentrate.
Magnetic separation. Rougher and cleaner low-intensity magnetic separation removes a magnetic product to rejects. High-intensity magnetic separation then recovers the rare earth-bearing magnetic minerals as concentrate and rejects the non-magnetic tails. Tails are filtered and sent to the MagSep tailings facility. The concentrate is reground and classified.
Hydrometallurgy. The concentrate is ground, classified and leached with sulfuric acid, and the solids are washed. Limestone neutralizes the solution, producing gypsum for tailings disposal. Impurities are removed, and soda ash precipitates a rare earth carbonate. Hydrometallurgical tailings are neutralized and sent to their own disposal facility.
Purification. The rare earth carbonate is treated to dissolve impurities, then redissolved. Solvent extraction with organic solvents, followed by stripping, separates the rare earths, and heavy and light rare earth products are precipitated separately.
Additional Interesting Data and Summary
A geotechnical and hydrogeological investigation of 14 boreholes and 14 test pits found generally uniform ground under the process plant site, with bedrock at 1.10 to 10.64 m depth. Groundwater flows from west to east toward the wetlands and the Des Jardins River. The report adds that the instantaneous throughput of crushing and grinding typically varies by plus or minus 20%, so the downstream equipment was sized with extra capacity.
In summary, the 2013 Kipawa feasibility study is an integrated rare earth flowsheet that upgrades ore by magnetic separation to a concentrate holding 45% of the feed mass, then leaches, precipitates and purifies it on site into separate heavy and light rare earth products.
Key Processes
- Open-circuit roll and cone crushing
- Grinding with cyclone desliming
- Low-intensity magnetic separation (rejects)
- High-intensity magnetic separation (concentrate)
- Concentrate regrind and sulfuric acid leaching
- Limestone neutralization and impurity removal
- Soda ash precipitation of rare earth carbonate
- Solvent extraction into heavy and light rare earth products
Source: Feasibility Study for the Kipawa Project, Matamec Explorations Inc., issue date October 17, 2013.
Earlier report summaries
Earlier versions of this profile, based on older technical reports, are retained below for source traceability. Dates and figures reflect each report’s own effective date and are superseded by the current information above.
Kipawa Project — 2012 Preliminary Economic Assessment
The 2012 Preliminary Economic Assessment for the Kipawa Project describes a two-site plant flowsheet comprising a mine-site crushing, grinding, and magnetic separation concentrator and a separate hydrometallurgical facility near Temiscaming, Quebec.
The Kipawa Project, as assessed in the 2012 Preliminary Economic Assessment prepared for Matamec Explorations Inc., is a rare earth oxides (TREO) development. The selected process configuration separates the ore beneficiation from the chemical treatment. The concentrator, located at the mine site, applies physical upgrading to produce a concentrate. This concentrate is then transported to a hydrometallurgical plant near the town of Temiscaming for further treatment. The design basis for the project is an annual feed of 1,500,000 tonnes of ore at a grade of 0.5% TREO, with a total TREO recovery of 81% targeted for the combined flowsheet.
Critical Data
| Parameter | Value | Unit | Notes |
|---|---|---|---|
| Annual feed | 1,500,000 | t ore/a | Mine site design criteria |
| Total rare earth oxide (TREO) grade | 0.5 | % | |
| Plant availability | 91 | % | |
| Daily ore tonnage | 4,516 | t/d | |
| Hourly tonnage | 188.2 | t/h | |
| TREO recovery to concentrate | 90 | % | |
| Concentrator tailings loss | 10 | % | |
| Hydromet residues loss | 9 | % | |
| Allowance for soluble loss | 1 | % | |
| Total losses | 20 | % | |
| Total TREO recovery | 81 | % | |
| Annual TREO production | 6,000 | t/a | |
| Concentrate | 35.0 | % of ore | |
| Concentrate | 65.9 | t/h | |
| Concentrate bulk density | 1.6 | t/m3 | |
| Concentrate TREO | 1.286 | % | |
| Thickener unit area | 0.4 | m2/tpd | Residue thickening |
| Filtration rate | 200.0 | kg/h.m2 | Residue filtration |
| Filter type | drum | Not stated | |
| Filtercake moisture | 25 | % | |
| Concentrator installed power | 4,675 | kW | |
| Concentrator operating power | 3,558 | kW | |
| Hydromet installed power | 5,067 | kW | |
| Hydromet operating power | 4,047 | kW | |
| Mine site genset capacity | 4.8 | MW | Diesel |
Overview
The project is an open-pit rare earth operation with a process design that is divided into two distinct locations. The mine-site plant performs crushing, grinding, and magnetic separation to create a concentrate. The design criteria state a feed rate of 188.2 tonnes per hour, which corresponds to 1,500,000 tonnes of ore per year. The concentrate produced is then transported by truck to a hydrometallurgical facility near Temiscaming. This separate plant receives the concentrate at a rate of 65.9 tonnes per hour and processes it to extract rare earth oxides.
Key Process Stages
The process commences with ore being hauled by trucks to a jaw crusher feed hopper. Crushed material is conveyed to a coarse ore bin with a live capacity of approximately 2,200 metric tonnes, sized for 12 hours of operation. From the bin, four vibrating feeders recover the stored material and feed the mill feed conveyor.
The crushed ore is sent to a semi-autogenous grinding (SAG) mill operating in open circuit, followed by a rod mill in closed circuit with a screen to produce a ground product. The ground material is then cycloned to remove fines below 200 mesh (75 microns). These fines are concentrated in rare earths and are thickened and taken as part of the final concentrate.
The magnetic separation stage uses low intensity wet magnetic separation (LIMS) to reject a magnetic concentrate. This is followed by wet high intensity magnetic separation (WHIMS) to recover rare earths as a concentrate, with the non-magnetic fraction rejected to tailings. The final concentrate is thickened, filtered, and stored in a silo before being shipped by truck to the hydromet plant.
At the hydrometallurgical site, the concentrate is re-ground in a ball mill prior to leaching with sulphuric acid in a train of atmospheric leach tanks. The resulting solution is processed through a solution circuit where the precipitate is filtered and calcined to yield a final product. The barren solution is recycled to the extent possible, with the balance reporting to the residue neutralization circuit.
Additional Interesting Data and Summary
The mine site electrical power requirement is estimated at 3.6 MW operating, with diesel gensets providing 4.8 MW of installed capacity. The hydrometallurgical facility has an operating power demand of 4.0 MW against an installed capacity of 5.1 MW. Design factors of 10% to 15% were applied to most equipment sizing to accommodate throughput variations. The tailings facility, with a total capacity of 11.7 Mm³, is assumed to be non-acid generating and therefore requires no watertight geomembrane. The tailings are designed with a 2.5H:1V slope, a crest width of 5 metres, and a maximum dyke height of 8 metres.
Key Processes
- Crushing (jaw crusher)
- Grinding (SAG mill, rod mill, ball mill)
- Magnetic separation (LIMS, WHIMS)
- Leaching (atmospheric sulphuric acid)
- Solution purification (precipitation and calcination)
- Tailings disposal (dry stacking)
Source: Kipawa Project , 2012 Preliminary Economic Assessment, 2012.
Project website: Kipawa Project, 2012 Preliminary Economic Assessment
