The 2020 Preliminary Economic Assessment for the James Bay Niobium Project outlines a processing flowsheet designed to treat 2,400,000 tonnes per year of ore, using gravity, magnetic, and flotation stages to produce a 60% Nb2O5 concentrate.
The recovery method for the James Bay Niobium Project is based on metallurgical test work described in Section 13 of the 2020 Preliminary Economic Assessment, combined with technology currently available and in use in the industry. The process flowsheet and design criteria are based on these test results and current industry practice. The flowsheet description is for an annual ore production rate of 2,400,000 tonnes per year at a process plant availability of 93%. A gravity circuit removes close to 42% of the mass early in the process, with limited niobium losses. This feature minimizes the energy required, considerably reduces the volume of pulp, and has a positive impact on reagent costs. Reagent consumption was estimated from the metallurgical test results.
The low grinding index of the ore and the coarse grind required for good liberation of the niobium mineral minimize the power requirement for grinding. A total of 1,900 kW was estimated for the entire grinding stage to prepare ore for processing; the flowsheet includes two stages of grinding with a gravity interstage. Grinding and gravity concentration are followed by pulp desliming, magnetic separation, and three steps of specific mineral removal prior to niobium flotation. The niobium concentrate is leached, filtered, and subjected to a final gravity separation to generate two different concentrate grades. The final concentrates are dried and bagged to generate the feed for the conversion process.
Critical Data
| Parameter | Value | Unit | Notes |
|---|---|---|---|
| Annual Ore Production | 2,400,000 | tpy | Design basis |
| Mill Throughput, Operation | 294.5 | tph | |
| Mill Availability | 93 | % | |
| Niobium Feed Grade | 0.53 | % Nb2O5 | |
| SAG Mill Power | 1,500 | kW | |
| Final Concentrate Grade | 60 | % Nb2O5 | |
| Nb2O5 Recovery in Final Concentrate | 78 | % | |
| Concentrate Tonnage | 16,412 | tpy | |
| Nb2O5 Production | 9,846,720 | kg | |
| Converter Nb Recovery | 96.5 | % | |
| Ore Moisture | 3 | % | |
| Specific Gravity | 2.8 | g/cm3 | |
| Ball Mill Product (Max Size) | 250 | μm | |
| Concentrate Leaching Retention Time | 12 | hour |
Overview
The James Bay Niobium Project is a development-stage project located in the James Bay region. The 2020 Preliminary Economic Assessment details a processing plant designed for an annual ore feed of 2,400,000 tonnes, corresponding to a mill throughput of 294.5 tonnes per hour at 93% availability. The flowsheet is designed to process ore with a feed grade of 0.53% Nb2O5. The process design criteria are based on metallurgical test work and current industry practice, as presented in the study.
Key Process Stages
Crushing is designed to reduce ore to less than 200 mm using a primary jaw crusher installed close to the process plant. This configuration applies to a scenario based on an open pit operation; if an underground operation becomes the ore source, crushing may be done underground before hoisting to surface. The primary crusher has a power rating of 375 kW, a feed size (F80) of 619 mm, and a product size (P80) of 150 mm.
Grinding consists of two steps in series with an interstage gravity circuit. Primary grinding is performed using a semi-autogenous (SAG) mill in closed circuit with cyclones, with a final product passing 500 microns. The SAG mill is rated at 1,500 kW. The cyclone product is further classified to remove the less than 74 microns fraction before feeding the gravity circuit. The gravity concentrate is reground in a ball mill in closed circuit to less than 250 microns prior to feeding the flotation circuit.
Additional Interesting Data and Summary
The final processing stage includes concentrate leaching with a retention time of 12 hours. The gravity recovery is stated as 58%, and the gravity concentrate tonnage is noted as 1,276,000 tpy. The process is designed to produce two niobium concentrate grades, a low silica and a standard silica grade. Sixteen different reagents will be used in the processing flowsheet, with the type and consumption refined in future metallurgical test work.
Key Processes
- Crushing (primary jaw crusher)
- Grinding (SAG mill and ball mill with interstage gravity circuit)
- Desliming and magnetic separation
- Flotation (sulfide, mica, carbonate, and niobium)
- Concentrate leaching (hydrochloric acid)
- Filtration, drying, and bagging
Source: James Bay Niobium Project , 2020 Preliminary Economic Assessment Study, 2020. Project website: Niobay Metals
Project website: James Bay Niobium Project, 2020 Preliminary Economic Assessment Study
