The Duparquet Gold Project Preliminary Economic Assessment describes a 15,000 t/d conventional comminution and flotation flowsheet designed to produce a gold concentrate for sale to smelters and roasters.
Report context
This Preliminary Economic Assessment (PEA) for the Duparquet Gold Project is dated October 2023. The report presents a preliminary process plant design based on previous metallurgical test work, industry standards, and conventional unit operations. The proposed plant is designed to treat gold-bearing material from an open pit and produce a gold concentrate for export.
Processing route
Primary Crushing
Mineralized material from the open pit, at an estimated maximum particle size of 610 mm, will be transported to the plant by 65-tonne high-capacity road trucks. Trucks tip directly into the Run of Mine (ROM) bin. Material is withdrawn by a variable-speed apron feeder to a vibrating grizzly with approximately 100 mm aperture size. Oversize material reports to a jaw crusher operating in open circuit. A rock breaker and a grapple assist in breaking down oversize material retained above the jaw crusher. Crushed material from the crusher discharge and grizzly undersize are withdrawn by a sacrificial conveyor fitted with a belt magnet to recover trash metal. The sacrificial conveyor feeds a stockpile feed conveyor with a weightometer to monitor primary crusher throughput. A single dust collection system with extraction hoods, ducting, and a baghouse services the crushing circuit.
Crushed Material Stockpile
Crushed material is conveyed to a stockpile with a live capacity of approximately 8,150 tonnes, equivalent to 12 hours of mill feed. Two reclaim apron feeders with variable speed drives control the reclaim rate feeding the grinding circuit.
Grinding
Reclaimed material feeds a 9.75 m diameter by 4.88 m effective grinding length SAG mill with a 9,000-kW synchronous motor and VSD. A belt-scale on the SAG feed conveyor monitors feed rate. Process water maintains a 75% slurry discharge density in the SAG mill. SAG discharge passes through a trommel screen to remove grinding media scats and some pebbles. Trommel undersize reports to the cyclone feed pump box, combining with ball mill discharge. Trommel oversize is conveyed back to the SAG mill feed conveyor.
Slurry from the cyclone feed pump box is pumped to a hydrocyclone cluster for size classification. Cyclone overflow at a target product P80 of 100 µm flows by gravity to the rougher flotation conditioning tank. Cyclone underflow feeds a 7.9 m diameter by 10.36 m EGL ball mill with a 13,000 kW fixed speed motor. Ball mill discharge passes through a trommel screen and reports to the cyclone feed pump box.
Flotation
Cyclone overflow flows by gravity to a trash screen then into a rougher flotation conditioning tank providing 5 minutes conditioning time. The rougher flotation circuit consists of a single bank of four 500 m³ mechanical tank-cells. Rougher concentrate feeds a concentrate regrind circuit. Rougher tailings are pumped to a tailings dewatering circuit.
The regrind circuit grinds concentrate to a P80 of 38 µm. Regrind product feeds the first cleaner flotation circuit consisting of a single bank of three 100 m³ tank-cells. First cleaner concentrate is pumped to the second cleaner flotation circuit. First cleaner tailings are pumped back to the rougher feed. The second cleaner circuit consists of a single bank of five 10 m³ tank-cells. Second cleaner concentrate is pumped to concentrate dewatering. Second cleaner tailings return to the first cleaner circuit.
Concentrate Dewatering
Cleaner flotation concentrate is pumped to an 8 m diameter thickener. Flocculant promotes solids settling. Thickener overflow reports to the process water tank. Thickener underflow at 60% w/w solids is pumped to a filter feed tank, then to a pressure filter producing gold concentrate at approximately 9% moisture. Filtrate returns to the concentrate filter. Dewatered concentrate is loaded by front end loader into lined containers for export.
Tailings Handling
Rougher tailings are pumped to a 32 m diameter thickener. Flocculant promotes settling. Thickener overflow reports to the process water tank. Thickener underflow at 60% w/w solids is pumped to the tailings storage facility.
Reagents
Reagents are prepared on site and distributed via handling and makeup systems. Reagents include potassium amyl xanthate (PAX) collector, R208 collector, MIBC frother, and flocculant. Reagent preparation and storage facilities are located within containment areas designed to exceed the maximum content capacity of the largest tank. Storage tanks have level indicators, instrumentation, and alarms. Ventilation, fire and safety protection, eye wash stations, showers, and MSDS stations are provided. Sumps and sump pumps control spillage. Storage tank capacity stores one day of production.
Plant Services
Blowers supply low pressure process air to flotation cells. Air compressors provide plant and instrument air, with instrument air dried before distribution. Gland seal water from the raw water tank passes through 25 µm particulate filters. Process water consists of concentrate thickener overflow, flotation tailings thickener overflow, tailings reclaim water, and fresh makeup water, stored in a process water storage tank and distributed by duty-standby pumps.
Metallurgical Accounting
Metallurgical samplers generate shift composite samples for plant metallurgical accounting. Process streams with samplers include primary cyclone overflow and flotation tailings. A weightometer on the stockpile feed conveyor measures primary crushed tonnage. A weightometer on the SAG mill feed conveyor determines mill feed tonnage. A manual belt cut sampling point on the SAG mill feed conveyor allows collection of mill feed head grade samples for cross-validation and moisture determination.
Key reported parameters
| Parameter | Unit | Value | Basis |
|---|---|---|---|
| Nominal Annual Throughput | t/y | 5,475,000 | Design |
| Nominal Daily Throughput | t/d | 15,000 | Design |
| Crusher Plant Availability | % | 75 | Design |
| Process Plant Availability | % | 92 | Design |
| Average Gold Head Grade | g/t | 1.51 | Design |
| Average Gold Recovery | % | 89.5 | Design |
| ROM Maximum Size | mm | 610 | Design |
| Crusher Circuit Product Size (P80) | mm | 130 | Design |
| Stockpile Live Capacity | h | 12 | Design |
| SMC A x b | – | 27 | Testwork |
| Bond Ball Mill Work Index | kWh/t | 18.5 | Testwork |
| Bond Rod Work Index | kWh/t | 19.1 | Testwork |
| Grinding Circuit Product Size (P80) | µm | 100 | Design |
| Rougher Flotation Retention Time | min | 70 | Design |
| Cleaner 1 Flotation Retention Time | min | 25 | Design |
| Cleaner 2 Flotation Retention Time | min | 15 | Design |
| Overall Flotation Mass Pull | % | 4.3 | Design |
| Concentrate Regrind Size (P80) | µm | 38 | Design |
| Concentrate Thickener Underflow Density | % w/w | 60 | Design |
| Concentrate Filter Press Filtration Rate | kg/h/m² | 425 | Design |
| Tailings Thickener Underflow Density | % w/w | 60 | Design |
| MIBC Frother Consumption | g/t feed | 35 | Design |
| PAX Collector Consumption | g/t feed | 151 | Design |
| R208 Collector Consumption | g/t feed | 63 | Design |
| Flocculant Consumption | g/t feed | 33 | Design |
| SAG Mill Liners | per year | 1.6 | Design |
| Ball Mill Liners | per year | 1.3 | Design |
| SAG Mill Grinding Media (150 mm) | kg/t feed | 0.67 | Design |
| Ball Mill Grinding Media (75 mm) | kg/t feed | 0.98 | Design |
| Regrind Mill Grinding Media (15 mm) | kg/t feed | 0.50 | Design |
| Raw Water Makeup Requirement | m³/h | 300 | Design |
| Average Power Demand (process plant) | MW | 15 | Design |
| Connected Power | MW | 22.7 | Design |
| Average Running Load | MW | 17.4 | Design |
| Gold Price Assumption | USD/oz | 1,800 | Assumption |
| Exchange Rate | USD:CAD | 1.33 | Assumption |
Project website: https://www.firstmininggold.com/assets/duparquet-project/
Project website: https://www.firstmininggold.com/news/first-mining-announces-positive-preliminary-economic-assessment–for-the-duparquet-gold-project-quebec-canada
Technical qualifications
The process plant design is preliminary in nature and based on previous metallurgical test work, industry standards, and conventional unit operations. The PEA states that there are no mining, concentrating, smelting, refining, transportation, handling, sales, hedging, or forward sales contracts or arrangements for the Duparquet Project, which is typical at this development stage.
The report notes that the produced concentrate will be relatively clean with a gold grade of 31.5 g/t Au, but may be subject to penalties for contaminants or impurities depending on prevailing market supply at the time of tendering. Concentrate sale is expected to include a mixture of long-term and spot contracts.
The infrastructure section indicates that demolition of existing infrastructure from the former Beattie mine will be required. Relocation of the provincial road 393, which crosses the mine property and falls within the pit footprint, will be required before Year 2. The tailings storage facility is designed with a capacity of 34.5 million cubic metres, constructed in phases without liners, leveraging favourable existing topographic and ground conditions.
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Source: Duparquet Gold Project , Preliminary Economic Assessment, October 2023, Sections 1, 17, and associated sections.
