Overview
Stage | Preliminary Economic Assessment |
Mine Type | Open Pit |
Commodities |
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Mining Method |
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Mine Life | 15.9 years (as of Jan 1, 2024) |
The PEA is a standalone mine plan that has been undertaken to evaluate the conceptual expansion of the open pit below the base of the permafrost.
The 2024 PEA assumes the 2024 PFS has been completely mined out prior to PEA mining activities.
The PEA does not include any Mineral Resources from the Walsh Lake deposit. The Mineral Resources used in the 2024 PEA mine plan are exclusive of the pits mined out in the 2024 PFS plan and the associated Mineral Reserves or Mineral Resources inside of those pits.
The 2024 PEA mine plan includes Inferred Resources. |
Source:
p. 1
Seabridge Gold announced the results of an updated Preliminary Feasibility Study (the “2024 PFS”) for its 100%-owned Courageous Lake project located in Canada’s Northwest Territories.
Contractors
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Deposit Type
- Orogenic
- Vein / narrow vein
Summary:
Walsh Lake Mineralization
The Walsh Lake target is 10 km south of the FAT deposit, adjacent and south of the historical Tundra Gold Mine that was abandoned in 1999. The north part of this target area is connected by a road network that links to the FAT deposit. Walsh Lake is interpreted to be a series of structural zones, parts of which are on strike with the deposits exploited in the Tundra Gold Mine.
The Walsh Lake target area stretches one and a half kilometer south from the former mine. This area has undergone several generations of exploration, including some limited past drilling campaigns showing these gold occurrences were located near a regional stratigraphic contact, which could provide significant strike potential. Gold-bearing quartz veins are hosted in sheared rocks near the contact between metamorphosed graywacke and mafic volcanic rocks.
The metagraywacke units are fine to coarse sand size material with well preserved, laterally discontinuous, fining upward sequence of graded beds. This turbidite section is distinguished by the absence of volcanic and chemical sedimentary rocks intercalated in the Bouma beds. Metamorphosed mafic volcanic rocks are black to green-black, dense, finegrained, and typically show fragmental textures. These rocks are principally made up of fine hornblende and plagioclase laths, with localized irregular and fractured dark garnet crystals.
Drilling on the Walsh Lake contact zone consistently encou ........
Summary:
Pit Phase Design
The open pit development is designed as a conventional truck-shovel operation with 227-t autonomous trucks with 16 m3 and 12 m3 shovels. The mine design includes two nested pit phases to balance stripping requirements while satisfying the process plant requirements. The design parameters include:
• ramp width of 36 m
• maximum road grades of 10%
• bench heights of 10 m
• safety bench interval of 20 m
• variable slope angles by sector.
A minimum mining width between pit phases is allocated to maintain a suitable mining platform for efficient mining operations. This is established based on equipment size and operating characteristics. For this study, the minimum mining width generally conforms to 50 m, which provides sufficient room for two-sided truck loading, but where phases merge, it is sometimes less.
Open Pit Major Equipment Selection
The mine load and haul fleet will use diesel hydraulic excavators (22m3 bucket for waste and 12 m3 for mill feed) matched with autonomous 227-t trucks. Smaller excavators are used for mill feed to increase the mining selectivity and therefore mill feed recovery; these unit sizes are proven in operating mines around the world. All equipment is diesel powered.
Suitable drill sizes (228 mm hole size) are selected to match the size of truck/shovel equipment. Diesel hydraulic percussive drills with a hole size of 6.5 inches (165 mm) will be used for contr ........
Flow Sheet:
Primary Crushing
Run-of-mine material is hauled from the mine and stockpiled or directly tipped into the run-of-mine feed hopper. Material from the hopper is discharged by gravity to a vibrating grizzly screen where oversize is discharged into the primary jaw crusher. This oversize material is crushed, a modular rock breaker is included to manage large rocks that may exceed the crusher cavity size.
The primary crusher is designed to reduce material size to an 80% passing product size (P80) of 94 mm. A magnet is installed to remove any foreign metallic bodies from the crushed material prior to feeding it to the secondary screen. The primary crushing circuit has 60% operating availability and the design capacity of 481 t/h. Major equipment in this area includes the following:
• ROM hopper
• vibrating grizzly feeder
• rock breaker
• primary jaw crusher (110 kW)
• secondary screen feed conveyor
Secondary and Tertiary Crushing
The primary crusher discharge and vibrating grizzly undersize is transferred to the secondary screen by the crusher discharge conveyor. The conveyor is equipped with a belt magnet as well as a metal detector to remove any remaining metallic foreign bodies from the material. Screen oversize material is gravity fed into the secondary cone crusher. Crusher discharge and secondary screen undersize is conveyed to the tertiary screen. Both secondary and tertiary crushers are located in the same building for optimal site layout and efficient performance of dust collection system.
Tertiary crusher discharge combined with secondary screen undersize material and secondary crusher product istransferred to the tertiary screen by the same conveyor. Oversize from the tertiary screen is conveyed to the tertiary crusher surge bin which ensures the crusher is choke fed. Material that passes through the tertiary screen discharges onto the fine ore transfer conveyor which will deliver material to the stockpile. The material crushed by the tertiary crusher is reduced to an 80% passing product size (P80) of 9 mm at the screen undersize. Major equipment in this area includes the following:
• secondary screen (2 decks)
• secondary cone crusher (335 kW)
• tertiary screen (2 decks)
• tertiary crusher surge bin
• tertiary cone crusher (480 kW)
• crusher discharge conveyor
• fine material transfer conveyor
• fine material stockpile (12 hour live capacity).
Primary Grinding and Classification
Reclaim belt feeder transfers fine material from the stockpile onto the ball mill feed conveyor which feeds the ball mill. The grinding circuit is designed for an annual operating time of 7,884 h or 90% availability and a nominal throughput of 347 t/h. The circuit is sized based on a grinding circuit feed size (F80) of 9 mm and a circuit product size (P80) of 106 µm. Process water is added to the ball mill feed to maintain the mill discharge slurry density at 70% solids. The ball mill product slurry will discharge onto a rubber-lined trommel screen, and the oversize is screened out and discharged to a scats bin, whereas the trommel undersize flows by gravity into the cyclone feed pumpbox, where the material is pumped to the cyclone cluster.
Promoter and copper sulphate are added to the cyclone feed pumpbox to activate gold-bearing sulphides for downstream flotation. Cyclone overflow at a nominal solids content of 35% w/w reports to the flotation circuit. To feed the ball mill grinding media, FELs feed balls from a storage bunker to charging kibbles. Each kibble opens into feed bins. Mobile feeders receive the grinding media from the openings at the bottom of the ball feed bins and transfer the balls into the ball mill feed box. Major equipment in this area includes the following:
• ball mill feed conveyor
• ball mill (6.5 MW)
• primary cyclone cluster.
Flow Sheet:
Summary:
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Source:
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Reserves at January 5, 2024:
base case cut-off grade of 0.8 g/t
Category | Tonnage | Commodity | Grade | Contained Metal |
Indicated
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44,737 kt
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Gold
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2.67 g/t
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3,841 koz
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