Champion Minerals' January 2013 prefeasibility study for the West and East Pit deposits of the Fire Lake North iron project near Fermont, Québec, expects an average of 8.7 Mt a year of concentrate over the first 20 years.
The Preliminary Feasibility Study of the West and East Pit Deposits of the Fire Lake North Project, Fermont Area, Québec, NI 43-101 Technical Report, was prepared by BBA Inc. with P&E Mining Consultants and Rail Cantech for Champion Minerals Inc. (later Champion Iron Mines Limited), and is effective January 25, 2013. The concentrator uses a conventional gravity flowsheet typical of Labrador Trough iron operations: gyratory crushing, a single autogenous (AG) mill, three stages of spiral concentrators, and pan filtration of the concentrate. The report notes that process design and equipment sizing ran almost in parallel with the testwork. As a result, recovery and ore hardness were estimated from BBA's experience and earlier limited testwork, and the design parameters differ somewhat from the Section 13 testwork results and are to be reviewed in the next phase.
Critical Data
| Parameter | Value | Unit | Notes |
|---|---|---|---|
| Report effective date | January 25, 2013 | Not applicable | BBA Inc. for Champion Minerals Inc. |
| Mill feed | 23 | Mt/a | Plant utilization 92% |
| Head grade | 30.0% FeT average, 35.4% high grade | Not applicable | First 20 years |
| Concentrate | 65% FeT, 5% SiO2 maximum | Not applicable | Not applicable |
| Iron recovery | 82.0 West Pit, 76.5 East Pit | % | Assumed from similar operations |
| Weight recovery | 37.8 average, 44.7 high grade | % | Not applicable |
| Concentrate production | 8.7 Mt/a average; up to 10.3 Mt/a | Not applicable | Higher in the early high-grade years |
| Primary crusher | 60 x 89 inch gyratory | Not applicable | Two dump points |
| Stockpile | About 34,250 t live (12 hours) | Not applicable | Three apron feeders |
| AG mill | 11.6 x 6.6 m, 16,000 kW dual pinion | Not applicable | 2,854 t/h nominal |
| Concentrate moisture | About 3% (steam-dried in winter) | Not applicable | Pan filters |
Overview
The plant is designed around 23 Mt a year of mill feed, the rate a single AG mill can achieve at the expected ore hardness and grind size. Concentrate handling equipment is sized for the high-grade case of 10.3 Mt a year, and tailings equipment for the average case of 14.3 Mt a year of tailings, both with a 15% design margin. The report considers its relatively high 92% availability appropriate because of extra equipment: a backup pan filter, oversized classification screens, and two independent circuits downstream of the scalping screens, so the plant can run at half capacity during maintenance. The water balance shows that precipitation, runoff into the tailings pond and pits, and water in the tailings slurry can meet process needs without fresh water make-up.
Key Process Stages
Crushing and stockpiling. Mine trucks tip at one of two dump points into the 60 by 89 inch gyratory crusher. Product passes a surge pocket and apron feeder to a conveyor and a stockpile with about 34,250 t of live capacity. Three apron feeders in a reclaim tunnel feed the mill conveyor.
AG milling and screening. The 11.6 by 6.6 m AG mill, driven through dual pinions by 16,000 kW of induction motors, is designed to treat ore at the 65th percentile of hardness using 85% of its installed power. It also allows for 10% swings in hardness and 15% in throughput. Mill discharge passes primary scalping screens and secondary multi-slope banana screens. Oversize from both, and coarse middlings from the cleaner spirals, return to the mill.
Rougher spirals. Classification screen undersize feeds the rougher spirals. Their concentrate goes to the cleaner spirals and their tailings to the tailings circuit.
Cleaner and recleaner spirals. Cleaner spirals make a concentrate, fine middlings, and coarse middlings that return to the AG mill. Recleaner spirals produce the final concentrate, plus coarse middlings that return to rougher feed and fine middlings. Cleaner and recleaner fine middlings and filtrate go to dewatering cyclones, whose underflow returns to rougher feed.
Concentrate dewatering. Pan filters dewater the concentrate, with steam hoods used in winter to reach about 3% moisture and prevent freezing in transit. A conveyor takes it to the train load-out.
Tailings. Rougher tailings are cycloned. The coarse underflow goes straight to the tailings pump box, and the fine overflow is thickened. Coarse and fine tailings are pumped together to the tailings pond through a single pipeline, and thickener overflow returns to process water.
Additional Interesting Data and Summary
The report notes that the plant's conveying systems have no redundancy. The design throughput of 2,854 t/h is set by AG mill power, and the iron recovery and concentrate grade in the mass balance are based on similar regional operations.
In summary, the 2013 Fire Lake North PFS is a large, low-cost gravity iron flowsheet: one AG mill and three stages of spirals upgrading 30% iron ore to a 65% iron concentrate at 8.7 Mt a year, with its design parameters still to be reconciled with the latest testwork.
Key Processes
- Gyratory crushing and stockpile reclaim
- Single-stage autogenous milling
- Two-stage screening with oversize recirculation
- Rougher, cleaner and recleaner spiral concentration
- Middlings recycle and dewatering cyclones
- Pan filtration with winter steam drying
- Combined coarse and fine tailings pumping to a pond
Source: Preliminary Feasibility Study of the West and East Pit Deposits of the Fire Lake North Project, Fermont Area, Québec, Canada, NI 43-101 Technical Report, BBA Inc. for Champion Minerals Inc., effective January 25, 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.
Fire Lake North — 2012 Updated Preliminary Economic Assessment
This updated preliminary economic assessment for the Fire Lake North project reports conceptual study outcomes based on 2011 mineral resource estimates and metallurgical testwork.
Report context
Champion Minerals Inc. commissioned BBA Inc. to prepare a second technical report on its wholly owned Fire Lake North project in the Fermont region of Quebec, Canada. The report incorporates a mineral resource estimate completed by P&E Mining Consultants Inc. and uploaded to SEDAR on November 17, 2011, and provides information on an updated preliminary economic assessment (PEA update) based on those mineral resources. The effective date of the mineral resource estimate is September 30, 2011, and the report signing date is January 4, 2012.
Processing route
Process design basis
The process design for the PEA update assumed a single line concentrator with an annual feed rate of 23 Mtpa, based on an estimated maximum autogenous grinding (AG) mill throughput. The design was developed from general process design criteria including concentrate production and nominal and design production rates. The process flowsheet and mass and water balance were prepared as part of the study.
Crushing, conveying and storage
The process plant description includes a crushing, conveying and storage section. Run-of-mine ore is delivered to primary crushing and a crushed ROM stockpile area before being fed to the concentrator.
Grinding and screening
Grinding and screening operations were designed following the process design criteria. Primary grinding mill sizing was determined based on throughput and tonnage, with mill pinion power draw calculated accordingly. Grinding testwork completed at SGS-Lakefield provided SPI and Ci crushing and grinding results used to support mill sizing.
Gravity spiral circuit
The flowsheet incorporates a gravity spiral circuit for iron recovery. The spiral circuit receives feed from the grinding and screening section and produces concentrate and tailings streams. Particle size distributions for spiral feed, concentrate and tailings streams were determined during testwork.
Concentrate conveying and loadout
Concentrate is conveyed from the spiral circuit to a concentrate loadout area. The site plan includes a concentrate loadout area as part of the overall site infrastructure.
Tailings dewatering and pumping
Tailings from the gravity spiral circuit are dewatered and pumped to a tailings pond. Tailings disposal infrastructure was included in the project design.
Concentrate and tailings production
Simplified production rates of concentrate and tailings were estimated based on the assumed iron recovery of 82% and the weight recovery assumptions for the first five years (43.2%) and first 25 years (38%) of operation. An average production rate of 8.7 Mtpa of concentrate over the first 25 years was estimated, with an average production rate of 10 Mtpa of concentrate over the first five years.
General concentrator plant services
The concentrator plant design includes compressed air, fresh water, process water, fire protection, and steam services. A major process equipment list was compiled for the PEA update.
Historical testwork
Historical testwork on Fire Lake North material included Wilfley table tests completed in 2010 on 20 mesh material, optical microscopy of various size fractions (-28+35 mesh, -35+48 mesh, and -65+100 mesh at 10X magnification), and heavy liquid separation tests completed in 2010 on 20 mesh material.
Updated PEA testwork (2011)
Updated testwork for the PEA was conducted in two phases. An initial series of heavy liquid separation tests at 20 mesh was performed at COREM in January 2011. Further heavy liquid separation testing at various mesh sizes was completed at SGS-Lakefield. Head assays were completed for Fire Lake North samples. Liberation size determination was carried out to establish the grind size required for adequate liberation of specular hematite. Concentrate quality was assessed and expected concentrate quality was reported. Particle size distributions were determined for spiral feed, concentrate and tailings streams. Grinding testwork provided SPI and Ci results for mill sizing.
The heavy liquid separation testing indicated that a grind size of 100% passing 28 mesh (600 µm) was required in some cases to realize an acceptable iron grade greater than 65% Fe in the final concentrate. Composite samples requiring this finer grind tended to have finer-grained specularite (hematite) mineralization. The PEA update assumed a 28 mesh grind size would be required; previously, a 20 mesh grind size had been determined based on a limited number of samples. The report notes that it is still premature to provide a definitive grind size for the project, as the deposits are comprised of both coarse-grained and finer-grained specularite and their relative proportions are not yet fully understood.
Key reported parameters
| Parameter | Value | Basis |
|---|---|---|
| Annual concentrator feed rate | 23 Mtpa | Design (based on estimated maximum AG mill throughput) |
| Assumed iron recovery | 82% | Design assumption |
| Average concentrate production (first 25 years) | 8.7 Mtpa | Design estimate |
| Average concentrate production (first 5 years) | 10 Mtpa | Design estimate |
| Average head grade (first 5 years) | 34.2% Total Iron | Design estimate |
| Weight recovery (first 5 years) | 43.2% | Design estimate |
| Weight recovery (first 25 years) | 38% | Design estimate |
| Grind size (assumed for PEA) | 100% passing 28 mesh (600 µm) | Testwork (HLS at COREM and SGS-Lakefield) |
| Concentrate grade target | Greater than 65% Fe | Testwork indication |
| Stripping ratio (first 5 years) | 2.46:1 | Design estimate |
| Stripping ratio (first 25 years) | 3.8:1 | Design estimate |
| Total combined measured, indicated and inferred resources (engineered pits) | 921.8 Mt at 28.9% Fe | Mineral resource estimate |
Project website: https://iaac-aeic.gc.ca/050/evaluations/proj/80014
Technical qualifications
The report states that a preliminary economic assessment is a conceptual study in nature as it uses inferred mineral resources that are not considered to be sufficiently defined to have the economic considerations applied to them that would enable them to be categorized as mineral reserves. There is no certainty that the conclusions reached in the report will be realized. Mineral resources that are not mineral reserves do not have demonstrated economic viability.
Metallurgical testwork reliance is noted in Section 3.2 of the report. The report notes that it is still premature to provide a definitive grind size for the project, as the deposits are comprised of both coarse-grained and finer-grained specularite and their relative proportions in the deposits are not yet fully understood.
Source: Update of the Preliminary Economic Assessment On the Fire Lake North Project, Fermont Area, Quebec, Canada, NI 43-101 Technical Report, effective date November 21, 2011, signing date January 4, 2012.
