This feasibility study for the BlackRock Metals Southwest Pit project describes the process flowsheet and design criteria for an open-pit mine, a magnetite beneficiation plant, and an integrated metallurgical complex producing high purity pig iron, titanium slag, and vanadium slag in the Chibougamau region of Québec.
The Southwest Pit feasibility study, dated March 2024, presents the process design for a fully integrated operation, from open-pit mining through to value-added metal production. The flowsheet was developed by integrating laboratory data, pilot plant results, and process design criteria. Recovery testwork was conducted at COREM in Québec City, with pilot-scale work using drill core selected from within the proposed pit design at the time of testing. The beneficiated product is a magnetite concentrate which, after dewatering, is transported to a downstream metallurgical plant located near Port Saguenay. The metallurgical complex will transform the vanadium-bearing titanium magnetite (VTM) concentrate into high purity merchant pig iron, titanium slag, and vanadium slag using a direct reduction and smelting route. The generalized process flowsheet is designed to depict the process simply, without necessarily showing the proper number of pumps, conveyors, and auxiliary systems.
Critical Data
| Parameter | Value | Unit | Notes |
|---|---|---|---|
| Annual Throughput (average) | 3.13 | Mtpy | Southwest Pit |
| Operating hours | 8,000 | h/y | Design value throughout |
| Pellet plant nominal production | 904,000 | t/y | Fired screened pellets |
| Fired pellet basicity | 0.6 | – | Design specification |
| Pellet plant operating hours | 8,000 | h/y | Not stated |
| VTM concentrate blaine surface area | 1200–1400 | cm²/gm | Design specification |
| DRI feed temperature | 600 | °C | To smelting furnace |
| DRI metallization | 94 | % | Design specification |
| DRI carbon content | 4.3 | % | Design specification |
| DRI nominal hourly capacity | 88.9 | t/h | Hot DRI |
| DRI nominal annual capacity | 711,245 | t/y | Hot DRI |
| Smelting operating hours | 8,000 | h/y | Design value |
| Smelting availability | 91.3 | % | Design value |
| Smelting utilization | 95 | % | Design value |
| Smelting operating factor | 86.8 | % | Design value |
| Process air pressure | 45 | psi | 510 SCFM per compressor |
| Plant air pressure | 125 | psi | 589 CFM per compressor |
| Cooling water inlet temperature | 30 | °C | Constant design value |
| Grinding power (ball mill) | 9,000 | kW | Per unit |
| DRI operating hours | 8,000 | h/y | Direct reduction plant |
Overview
The project comprises a magnetic separation beneficiation plant and an integrated metallurgical facility. The concentrator is designed around conventional crushing, grinding, and magnetic separation to produce a magnetite concentrate. The metallurgical plant, located near Port Saguenay, will use the concentrate as feed for pelletizing, direct reduction, and smelting. The iron ore reduction process was selected based on comparisons relevant to energy requirements, environmental impact, plant size, infrastructure, and reference plants. The final process selection resulted in the use of the Energiron direct reduction process, followed by an Open Slag Bath Furnace (OSBF) for smelting. The principal energy source for the overall project is electricity, with the exceptions of diesel for mine equipment and natural gas for the pelletizing and direct reduction plants.
Key Process Stages
The process flowsheet begins with crushing of run-of-mine ore. The primary crushing circuit consists of a grizzly feeder with an opening of 75 mm to 100 mm, allowing fine material to bypass the jaw crusher. Oversized material is fed to the jaw crusher, which is designed for a maximum rock size of 1.5 m. Crushed rock and bypassed fines are combined downstream. Grinding is achieved in a ball mill with an expected volumetric load between 30% and 35%, operating at 60% to 75% of critical speed. Upgrading occurs in a secondary magnetic separation stage, with cleaning and re-cleaning taking place in the same unit. The concentrate is dewatered using disc filters and stored on stockpiles managed by front end loaders.
Reagent and water systems are integrated, with solids density controlled at 50% solids (w/w) before final tailings are pumped to the tailings pond. The majority of process water requirements are fulfilled by recycling process water via the tailings thickener, which also serves as the source of process make-up water. Air generation for the process is provided by two operating compressors and one standby, each supplying 510 SCFM at 45 psi. Plant and instrument air is supplied by two operating and one standby compressor, each providing 589 CFM at 125 psi. The cooling system is a closed-circuit water loop with all process equipment connected in parallel, maintaining a constant inlet temperature of 30°C and constant volume flow.
At the pelletizing plant, the key design parameters include a nominal production of 904,000 tonnes per year of fired screened pellets. The fired pellet basicity is specified at 0.6. The VTM concentrate blaine surface area is between 1200 and 1400 cm²/gm. The straight grate process was selected; currently, all pellets produced in Canada of both blast furnace and direct reduction grade use this technology. Testwork has confirmed particle size distribution, typically 100% passing 200 mesh (74 μm), fired pellet chemistry, physical and metallurgical properties, and additive feed rates. Recycled dust is precisely metered, though its inclusion in additive feed rate determination is not required. If the direct reduction feed bins are full, pellets can be diverted to an 8,000-ton storage pile, equivalent to three days of storage.
The direct reduction plant is designed around the Energiron process, producing hot DRI. The reactor has a nominal hourly capacity of 88.9 tonnes per hour, feeding the smelting furnace. Testwork confirmed a metallization of 94% and carbon content of 4.3%. Direct reduction plant availability is designed for 91.3%, with an operating factor of 86.8%. The metallurgical plant layout was defined in cooperation with Tenova, with the heaviest equipment located on areas where bedrock is closest to the surface, requiring some additional cut and fill to level the site to 140 m above sea level.
The smelting plant consists of the smelter and a ladle furnace. The furnace design is based on 95% utilization, corresponding to industry norms. The OSBF operates using DRI as the raw material, anthracite as reductant, and immersed electrodes in the slag. The average reactor capacity of 113 t/h of hot DRI feeds the furnace. Refined hot metal is fed to a pig caster to produce High Purity Pig Iron or Nodular Pig Iron (HPPI/NPI), following a 2.5-hour tapping sequence. The vanadium slag is sent to a third-party transformation plant for vanadium extraction and ferrovanadium production.
Additional Interesting Data and Summary
Energy consumption is distributed across the process areas. Natural gas is the main fuel for the pelletizing plant at approximately 0.1 Gcal per tonne of pellets, and is also the fuel source for the direct reduction plant. The power consumption design value for the direct reduction area is 5.6 MW. Grinding circuits represent 60% of the total operating energy demand for the concentrator. Most of the energy supplied to the direct reduction process is taken by the product, with minimum energy losses to the environment.
The smelting furnace was designed based on a DRI feed temperature of 600°C and a utilization of 95%. The furnace operating hours are 8,000 per year, with an availability of 91.3%. The design basis for the smelting plant electrical power includes the total transformer capacity. The molten metal temperature is critical to the process, particularly for the tapping sequence and subsequent casting.
Key Processes
- Open-pit mining with conventional drilling and blasting, constrained by a 1.5 m maximum crusher feed size
- Primary crushing via grizzly feeder (75–100 mm opening) and jaw crusher
- Ball milling at 9,000 kW per unit with 30–35% volumetric load at 60–75% critical speed
- Magnetic separation with in-unit cleaning and re-cleaning stages
- Disc filter dewatering of magnetite concentrate
- Straight grate pelletizing producing 904,000 t/y of basicity 0.6 pellets
- Energiron direct reduction producing 94% metallized hot DRI at 88.9 t/h
- Open Slag Bath Furnace smelting of hot DRI at 600°C feed temperature
- Pig casting producing high purity pig iron and nodular pig iron
- Vanadium slag production for third-party ferrovanadium processing
Source: Feasibility Study of the Southwest Pit , 2024 Technical Report, March 2024.
Project website: Feasibility Study of the Southwest Pit, 2024 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.
Feasibility Study of the Southwest and Armitage Pits — 2014 Technical Report
This NI 43-101 technical report, dated June 2014, describes the proposed mineral processing flowsheet for the recovery of magnetite and ilmenite concentrates from the Southwest and Armitage pits.
Report context
The June 2014 NI 43-101 Technical Report presents the feasibility study for the Southwest and Armitage pits, detailing the proposed processing route for run-of-mine ore. The report includes results from testwork performed at COREM in Québec City and at SGS in Lakefield, Ontario, which supported the selection of a beneficiation process flowsheet. The process flowsheets were designed by combining information from laboratory and pilot plant experiments, engineering experience on similar projects, and supplier input.
Processing route
Crushing and Ore Handling
Run-of-mine ore will be delivered by trucks with a 226-tonne capacity to two dump points located at a 54” x 75” gyratory crusher. The crusher was sized with a utilization of 65%, having a 2,335 tph (dry) instantaneous capacity. A hydraulic rock breaker will be installed adjacent to the crusher, and the crusher will be equipped with a main shaft positioning system. Crushed rocks, ranging from 0–12” in size, will pass through a surge pocket with a minimum 2-truck capacity. Crushed rock will be reclaimed by an 84” wide apron feeder directing material to a belt conveyor approximately 200 m long sized to handle 2,350 tph.
A stage of secondary crushing is necessary to maximize SAG mill throughput. A 1,000 HP cone crusher will reduce incoming oversize particles from the classification screen from a P80 of approximately 190 mm to 50 mm. The transfer conveyor from the gyratory crusher will feed a storage bin with 10 minutes of live retention time. A vibrating feeder will feed a double-deck screen with openings of 180 mm and 50 mm. A bypass chute allows tramp metal to bypass the screen and also allows bypass of the secondary crusher during maintenance. Screen undersize falls onto a crushed ore collecting conveyor; screen oversize is directed to the cone crusher feed.
The crushed ore will be transported via belt conveyor to a stockpile measuring 46 m by 115 m with a live storage capacity of approximately 9 hours. Five belt feeders will reclaim the crushed material, each capable of providing half of the full 1,576 tph feed (dry basis) to the reclaim belt conveyor.
Primary Grinding (SAG Circuit)
The SAG mill will be 36 ft in diameter x 17.25 ft long (flange to flange) with a total installed power of 15,000 kW. Forged steel balls, 5 inches in diameter at a total ball charge of 11–14% (v/v), will be used for grinding. A variable frequency drive (VFD) will be used for grinding control.
SAG discharge will be sent to a scalping screen; oversize goes to the recycle conveyor. Scalping screen undersize will be pumped to multi-slope screens. Multi-slope classification screen undersize will report to a pump-box and be pumped to magnetic cobbing; oversize is recycled to the SAG mill. A density meter will control process water addition to the pump-box feeding the magnetic separators, ensuring 40% (w/w) slurry density. An eight-way distributor will feed each magnetic separator feed box.
Primary Magnetic Separation (Cobbing)
Eight single-drum counter-rotation wet low intensity magnetic separators (diameter x width = 1,219 x 3,810 mm) will treat a design rate of 1,686 tph of ground ore at -3.0 mm (D100). Non-magnetic tailings will be collected in a large launder. The cobber tails will be separated into coarse and fine fractions using hydrocyclones. The magnetic concentrate will be sent by gravity to the ball mill discharge slurry pump-box.
Secondary Grinding
The cobber magnetic concentrate, along with ball mill discharge, will pass through a cyclone cluster. Overflow will continue to a second stage of magnetic separation. Underflow (U/F) at 75–80% (w/w) solids will be returned to the ball mill feed chute. The recirculating load in the ball mill closed circuit is taken to be 250%. The cyclone cluster, with 800 mm diameter cyclones, was designed with two spare cyclones per four operating cyclones to handle a potential 350% recirculating load.
A ball mill sized at 21 ft in diameter x 35 ft long (flange to flange) will achieve the desired re-grind size of P80 = 75 µm. The ball mill was sized to handle a design tonnage where 50% of the cobber feed reports to the ball mill. Nominally, 39% weight recovery from cobbing to the ball mill would be expected. The ball mill will have an installed power of 8,950 kW (12,000 HP) and will be equipped with a VFD.
Cleaning Magnetic Separation
Overflow from the ball mill circuit cyclones will be pumped to an eight-way distributor (2 blanks) feeding the secondary magnetic separation stage. Six double-drum, counter-current type, wet low intensity magnetic separators (diameter x width = 1,219 x 3,810 mm) will clean the cobber magnetic concentrate. The cleaning stage consists of two drums: a cleaner and a re-cleaner. Secondary magnetic separation tailings will be sent to the Fe non-mag SMS fines pump-box.
Magnetite Concentrate Desulfurization
The secondary magnetic separator concentrate will be fed to a flotation circuit consisting of six tank cells arranged in a 2-2-2 series configuration. A collector (PAX) and a frother will be added in a pre-conditioning tank. The sulphide flotation product will overflow into launders and be sent to the tailings thickener pump-box. The flotation underflow is the upgraded, desulfurized magnetic concentrate.
Magnetite Concentrate Dewatering
The upgraded magnetite concentrate will be fed to a 22 m diameter insulated concentrate thickener located outside the plant. The thickener will also receive filtrate from the drum filters and will be equipped with an auto-dilution system to dilute feed concentration to 17–19% solids by weight. The thickener underflow will have a 65–75% (w/w) solid maximum (design at 75%) and will be pumped to a filter feed agitated slurry tank.
From the filter feed agitated slurry tank, slurry will be pumped by four VFD slurry pumps, each feeding a drum filter with 80 m² of filtration area. Four drum filters will be required with steam addition to obtain a filter cake with 5.5% moisture. Each filter unit was designed to handle approximately 110 tph of filter cake at the targeted maximum moisture. Four vacuum pumps connected to a common header will produce the required vacuum.
Ilmenite Beneficiation
The tailings from the magnetite beneficiation circuit will be separated into fine (-106 µm) and coarse (+106 µm) material. The coarse fraction will pass through multi-stage gravity separation via spirals. The gravity concentrate will then be ground via ball mill in closed circuit with hydrocyclone classification. The fine material from the magnetite circuit will be dewatered and sent to a multi-stage gravity spiral circuit. The concentrate from the fine gravity circuit will be combined with the hydrocyclone overflow from the coarse concentrate regrind. The combined flow will pass through multi-stage magnetic separation before being sent to multi-stage flotation.
The froth from the flotation circuit will be dewatered via a thickener and drum filtration. Acidified tailings from flotation stages will be neutralized prior to being combined with non-acidified tailings. Coarse and fine tailings will both be pumped to treatment ponds.
Cobber Tailings Cyclone
Cobber non-magnetic tailings will be collected in a pump-box before being pumped to a single cluster of cyclones. The cyclones will separate material into +106 µm particles (underflow) and -106 µm particles (overflow). Coarse underflow will be sent to the coarse spirals circuit. Fine overflow will be sent to the SMS tailings pump-box and combined with non-magnetic fines from the SMS stage. The cyclone cluster includes three operating cyclones under nominal flow conditions with a fourth cyclone serving as a spare.
Coarse Tailings Gravity Circuit
Coarse tailings from the magnetite beneficiation plant will be pumped to a multi-stage spiral separation circuit. Incoming solids will be diluted, and wash water will be added to each spiral as per conditions determined in the spiral selection study performed at COREM. Tailings will be sent to a pump-box, then to coarse tailings cyclones, before being sent to a coarse tailings basin. Concentrate will be directed to a regrind circuit.
Fine Tailings Gravity Circuit
Fine non-magnetic tailings from the magnetite beneficiation plant will first be sent to a stage of dewatering cyclones to reach the target slurry density as per spiral selection studies performed at COREM. Four clusters of cyclones will each house 32 operating cyclones with four spares and eight blanked-off spots. The 150 mm diameter cyclones will dewater the incoming fine tailings and produce an underflow with most of the +20 µm solids.
Key reported parameters
| Parameter | Value | Basis |
|---|---|---|
| Gyratory crusher instantaneous capacity | 2,335 tph (dry) | Design |
| Gyratory crusher utilization | 65% | Design |
| SAG mill dimensions | 36 ft diameter x 17.25 ft long | Design |
| SAG mill installed power | 15,000 kW | Design |
| SAG mill ball charge | 11–14% (v/v), 5-inch forged steel balls | Design |
| Reclaim belt conveyor feed rate | 1,576 tph (dry basis) | Design |
| Crushed ore stockpile live capacity | Approximately 9 hours | Design |
| Cobbing magnetic separators | 8 units, single-drum, 1,219 x 3,810 mm | Design |
| Cobber design feed rate | 1,686 tph at -3.0 mm (D100) | Design |
| SAG mill feed slurry density | 40% (w/w) | Design |
| Ball mill dimensions | 21 ft diameter x 35 ft long | Design |
| Ball mill installed power | 8,950 kW (12,000 HP) | Design |
| Ball mill product size | P80 = 75 µm | Design |
| Ball mill recirculating load | 250% (design), 350% (capacity) | Design |
| Weight recovery from cobbing to ball mill | 39% (nominal) | Design expectation |
| Secondary magnetic separators | 6 units, double-drum, 1,219 x 3,810 mm | Design |
| Flotation cells | 6 tank cells in 2-2-2 configuration | Design |
| Concentrate thickener diameter | 22 m | Design |
| Thickener underflow solids | 65–75% (w/w) maximum (design at 75%) | Design |
| Thickener feed dilution | 17–19% solids by weight | Design |
| Drum filter area per unit | 80 m² | Design |
| Drum filter production per unit | Approximately 110 tph filter cake | Design |
| Filter cake moisture target | 5.5% (with steam addition) | Design |
| Cobber tailings cyclone split | +106 µm (coarse), -106 µm (fine) | Design |
| Fine tailings dewatering cyclones | 4 clusters, 32 operating + 4 spare + 8 blanked per cluster | Design |
| Fine tailings cyclone diameter | 150 mm | Design |
Technical qualifications
The report states that the process flowsheets were designed by combining information collected during laboratory and pilot plant experiments, BBA’s experience on similar projects, and supplier input. The ball mill was sized in order to handle a design tonnage where 50% of the cobber feed reports to the ball mill; fluctuations in Satmagan and potential poor-liberation could lead to higher ball mill tonnages. The recirculating load in the ball mill closed circuit is taken to be 250%, but the cyclone cluster was designed to handle a potential 350% recirculating load under nominal conditions. The report notes that three drum filters could handle the design tonnage but would require increased steam to reduce residual moisture to 5.5%. The 20% excess capacity designed into the ilmenite plant serves to handle daily fluctuations in feed due to the incoming feed being a tailings stream and higher tonnages in low grade years.
Source: NI 43-101 Technical Report, Feasibility Study of the Southwest and Armitage Pits, June 2014, Sections 1.18 and 17.
