This report presents the processing design for the Blue River tantalum–niobium project based on a 2011 preliminary economic assessment, with a nominal capacity of 7,500 tonnes per day.
Report context
This technical report, dated 22 June 2012, is a National Instrument 43-101 disclosure for the Blue River Tantalum–Niobium Project in British Columbia, Canada, owned by Commerce Resources Corp. The recovery methods section incorporates assumptions, analysis, and findings from a Preliminary Economic Assessment with an effective date of 29 September 2011.
Processing route
Plant design basis
The design for the process facilities considered a nominal processing capacity of 7,500 t/d. Where data were not available at the time of flowsheet development, design criteria for sizing and selection of equipment were developed based on comparable industry applications, benchmarking, and the use of modern modelling and simulation techniques.
The mineral processing and refining steps are based on conventional technology and industry-proven equipment.
Overall flowsheet concept
Run-of-mine mineralized material from the underground operation will be crushed and conveyed to the concentrator. The mineralization will be ground to liberate the mineral values from the host rock and then separated by flotation to produce a bulk tantalum–niobium concentrate.
The bulk concentrate will be filtered, dried, and introduced into the refining plant. In the refining plant, the concentrate will undergo a thermal reduction step to remove most of the gangue material and create a smaller, higher purity material for subsequent chlorine processing.
Distillation of the anhydrous metal chloride products will produce separated high-purity niobium and tantalum chlorides. Tantalum chloride is the precursor to capacitor-grade tantalum powder and would be marketed in this form. Niobium chloride can be sold as a chemical precursor. Both tantalum and niobium chloride products can be readily converted and marketed as high-purity technical grade Ta2O5 and Nb2O5 oxides, respectively.
Comminution
The primary crushing station will be a fixed jaw crusher. Mine haul trucks will dump run-of-mine mineralized material into a ROM surface stockpile located close to the Lower Portal. Mineralized material will be fed to the crusher using an apron feeder. Crushed mineralized material will fall onto a conveyor and be fed to a fine crushing circuit at the plant site which will further reduce the material to -8 mm. The material will be stored in a fine ore silo and withdrawn by feeder into a rod mill.
Rod mill discharge will flow into the cyclone feed pumpbox, which will transfer the material to the cyclone circuit. The cyclone circuit will produce finished product in the overflow at a P80 size of 100 µm. Cyclone underflow will report to a ball mill for additional grinding, with ball mill discharge joining the rod mill discharge as feed to the cyclone pumpbox.
Key reported parameters
| Parameter | Value | Basis |
|---|---|---|
| Nominal processing capacity | 7,500 t/d | Design |
| Primary crushing equipment | Fixed jaw crusher | Design |
| ROM feed arrangement | Surface stockpile near Lower Portal, apron feeder | Design |
| Fine crushing product size | -8 mm | Design |
| Grinding circuit | Rod mill, ball mill, cyclone | Design |
| Finished product grind size (cyclone overflow) | P80 100 µm | Design |
| Concentrate production route | Flotation to bulk Ta-Nb concentrate | Design |
| Refining route | Thermal reduction, chlorine processing, distillation | Design |
| Products | High-purity Ta and Nb chlorides; convertible to Ta2O5 and Nb2O5 oxides | Design |
Technical qualifications
The report states that the information relevant to the plant design supporting the financial analysis prepared during the 2011 PEA is included in the recovery methods section and has not been updated because AMEC considers that the assumptions supporting the outcomes remain reasonable. The effective date of the 2011 PEA results remains 29 September 2011.
Source: Technical Report on Mineral Resource Update, Blue River Tantalum–Niobium Project, British Columbia, Canada, dated 22 June 2012, Section 17.0 Recovery Methods.
