This technical report dated November 5, 2025, describes proposed dry crushing and screening processing methods for producing de-icing salt from the Great Atlantic Salt Project.
Report context
The November 5, 2025, NI 43-101 technical report for Atlas Salt Inc. presents the processing route for the Great Atlantic Salt Project. Salt from the mine will be processed to produce one product only: de-icing salt conforming to the ASTM D632-12 specification for road maintenance and construction. The report describes a proposed processing plant designed to handle up to 4.0 Mtpa, with historical operating data limited to existing port facilities previously used for gypsum and base metal concentrate storage. Testwork is referenced for salt abrasivity and crusher wear characteristics.
Processing route
Product specification
The finished salt product must meet ASTM D632-12 requirements for sodium chloride content (minimum 95% NaCl ±0.5%) and size grading. The standard specifies that de-icing salt is to be delivered in free-flowing form, requiring addition of an anti-caking agent prior to shipping. Customers typically expect a minimum concentration of 50 ppm yellow prussiate of soda (YPS), the most commonly used anti-caking agent. Size grading requirements are presented in Table 17-1 of the report.
Underground processing plant
Processing will be carried out in the underground mine and will consist of conventional dry screening and crushing using double roll crushers and inclined vibrating screens. An excavation approximately 190 m long, 20 m wide, and 20 m high, located at the bottom of a conveyor incline tunnel (one of the two parallel mine access declines), will accommodate the processing plant. The plant and associated conveyors and infrastructure have been designed to process up to 4.0 Mtpa. Excess processing capacity exists due to the inclusion of a 25% design factor on all key equipment and overland transport conveyors, which will allow the processing plant to increase production during seasonal high-demand periods and allow routine maintenance to be prioritized during periods of low demand while maintaining the overall 75% annual plant availability.
Fines minimization
A key constraint during processing is the minimization of fines generation, hence the use of roll crushers and multiple crushing and screening stages to minimize the reduction ratio at each stage of crushing, and where product-size material is screened out before each stage of crushing and directed to the product stockpile. Fine screens within the processing plant will remove excess minus 600 µm material from the crushed salt if necessary.
Crushing and screening stages
Mining will be carried out by continuous miners that will produce run-of-mine material with a top size of approximately 200 mm. Material larger than 200 mm may occasionally occur due to natural breakage of the salt during mining. The ROM material will be hauled to a pass where a feeder-breaker located at the bottom of the pass will reclaim the material from a stockpile and ensure that any oversize is broken before discharging it onto a transfer conveyor. The salt will be transported to the receiving bin at the processing plant on the 240 Level by a series of transfer conveyors from the initial mining level (320 Level) and later from the second (356 Level) and subsequent mining levels. The receiving bin will have a capacity of approximately 80 t.
Salt will be withdrawn from the receiving bin by a variable speed belt feeder that will meter the salt to the crushing plant in conjunction with a belt scale on the feed conveyor. A belt magnet and metal detector will remove metal from the plant feed conveyor or stop the conveyor before metal can enter the plant.
The first step in processing will consist of a grizzly feeder that will simultaneously feed the primary crusher while removing less than 64 mm material, which will bypass the primary crusher and report to the primary screens. Undersize (less than 12 mm) from the double deck primary screens will report to the product conveyor while the oversize from the top deck (greater than 45 mm) will report to the secondary crusher and oversize from the second deck (12 mm to 45 mm) will report either to the secondary or tertiary crusher via a diverter gate. This flexibility has been allowed for so that secondary and tertiary crusher loads can be optimized during operation.
The product from the secondary crusher will feed the tertiary screen where the oversize (greater than 10 mm) will report to the tertiary crusher and the undersize (less than 10 mm) reports to the fines screen. The final crushing stage (tertiary crushing) will be in closed circuit with the two quaternary screens operating in parallel, from which undersize or product-size material (less than 12 mm) will be directed to the product conveyor and oversize material (greater than 12 mm) will be returned to the tertiary crusher.
The tertiary crushing circuit has been designed to accommodate two tertiary crushers operating in parallel to achieve the design production rate of 4.0 Mtpa. However, initially only one tertiary crusher will be installed, with the second crusher installed in Year Two of operation as the mine ramps up production. In the single tertiary crusher configuration, the processing plant is estimated to be capable of processing between 3.0 Mtpa and 3.5 Mtpa.
There is no need and no allowance for intermediate storage between crushing and screening stages. Salt will be screened and crushed as it is produced by the previous stage.
Fines rejection circuit
A fines rejection circuit will form part of the tertiary screening circuit where fine material (less than 800 µm) in the secondary crusher product may be screened out if necessary and stockpiled separately and returned to the mine and used for road surfacing. This will allow for a portion of the fines in the crushed product to be rejected to ensure that the final salt product conforms to the specification for de-icing salt, with no more than 20% passing 600 µm. Oversize from the fines screen will be directed to the product conveyor. A diverter gate on the fines screen undersize chute allows for fines to be redirected to the product conveyor should the quantity of fines in the product not exceed the allowable limit.
Product handling and anti-caking addition
The final salt product will be sampled by an automatic cross-cut sampler for regular testing to ensure that it conforms to the specification. The product conveyor will deposit the final salt product onto the approximately 1,740 m long incline conveyor that will carry the salt to the surface. Transfer conveyors on surface will carry the salt from the incline conveyor to an overland conveyor that will transport the salt to storage buildings at the port.
A small storage facility near the mine portals will allow for storage of approximately 11,700 t of salt if downstream equipment requires maintenance, as well as for loading of trucks by front end loaders to supply local customers. Anti-caking agent (YPS) in solution form will be added to salt that will be stored in the facility and intended for the local market.
The overland conveyor, approximately 2,019 m in length, will transport the salt along an existing haul road and causeway to the port at Turf Point where it will be stored prior to shipping. The conveyor will pass through the outskirts of the town of Saint George's and will pass under the main road (route 461) west of the town and then over Beach Lane. The conveyor will be covered and fenced off for the part of the route outside of the town, and enclosed and fenced off where it passes nearby residential properties.
Port storage and ship loading
The existing storage and ship loading facilities at Turf Point are currently used for shipping gypsum mined at a quarry approximately 8.5 km southwest of the port and hauled to the port by truck along the haul road and through the town. This represents historical operating data for the existing facilities. The existing storage building at Turf Point, originally built and used for base metal concentrate storage prior to shipping, and subsequently for gypsum storage, will be modified to include conveyor delivery of salt.
The existing storage building and ship loading facilities at Turf Point, and a new storage building constructed for the Project will accommodate approximately 60,000 t of salt.
Salt will be shipped by bulk carriers, and shipment sizes may range from 25,000 t to 50,000 t. Salt will be reclaimed from the storage buildings by new underground vibrating feeders and existing belt feeders and conveyors for shipping via the existing 1,000 tph ship loader. YPS will be added to the salt in solution form prior to shipping and the salt will be sampled by an automatic cross-cut sampler as it is discharged onto transfer conveyors carrying the salt to the ship loader.
Consumables and reagents
Consumables will consist mainly of crusher wear parts and screen decks, as well as conveyor parts (idlers and return rollers), and lubricants. Testwork has indicated that the salt is not abrasive or only mildly abrasive, and crusher roll segments are expected to last several years before requiring replacement. Annual allowances have been included in the operating cost estimate to account for these items.
Only one reagent, YPS, will be used in the process, and will be added to the salt prior to shipping to limit caking. A dosage rate of 75 g/t has been allowed for, slightly higher than needed to meet the generally required minimum 50 ppm concentration. YPS will be delivered in the form of a crystalline powder in 500 kg bags and will be mixed with water at a concentration of 2% by weight and applied to the salt as a spray. Two YPS make-up and addition stations will be installed, one at the intermediate storage facility near the mine portals and one at the Turf Point Port. At a dosage of 75 g/t and a salt production rate of 2.5 Mtpa, YPS consumption will be 188 tpa.
Laboratory and plant control
A small laboratory will be located at the surface complex and will be capable of conducting simple chemical analysis for NaCl and insoluble content of salt samples, and size analysis of crushed salt. The laboratory will carry out analysis of shift samples for process plant monitoring and control, shipment samples, and analysis of mine grade control samples.
The plant control system (PCS) will comprise a programmable logic controller based architecture with a fibre optic backbone and remote input/output. Independent PCS and control rooms will be provided for the mine and port facilities and networked for monitoring purposes. All material handling and processing equipment will be monitored and controlled through the PCS.
Electricity and fuel consumption
Electricity will be supplied from the grid and consumption has been estimated from the mechanical equipment list, associated electrical motor sizes, and equipment utilization requirements to achieve 4.0 Mtpa of salt production. Installed power is estimated at approximately 2,607 kW, including processing, conveying to surface, storage, reclaim, and surface conveying, and excluding the overland conveyor and port. Annual consumption is estimated to be approximately 17,500 MWh with an average equipment utilization of 71%.
Fuel will be required for a small fleet of mobile equipment including personnel transport, maintenance vehicles, front end loaders, compact wheel loader, forklift, and mobile crane. A fuel storage facility will be located adjacent to the surface facilities.
Personnel
The processing plant and conveyor transport to the port are simple operations and will be largely automated requiring minimal operator intervention. At design capacity, the plant will operate 24 hours per day, 365 days per year. Shift workers will work on a twelve-hour shift basis. The total complement (all shifts) including management and supervision, operators, maintenance personnel, and laboratory personnel has been estimated at 37. Salt storage, reclaim, and ship loading at Turf Point will be carried out by the port owner on a contract basis.
Commissioning and ramp-up
Ramp-up to steady state throughput is anticipated to be achieved within weeks of starting up due to the simplicity of the plant and the small number of different types of equipment being used. Some optimization of crusher gap settings and screen deck openings to improve efficiency and ensure that individual pieces of equipment are operating within design parameters is expected to be required and may be completed over the first year of operation. However, the actual annual production rate will be dictated by other factors, including the supply of ROM salt from the mine and market penetration rate. The mine plan allows for ramp-up to an annual production rate of 4.0 Mt by the fourth year of operations.
Key reported parameters
| Parameter | Unit | Design Value | Basis |
|---|---|---|---|
| Annual Production Rate – Finished Salt (max) | tpa | 4,000,000 | Proposed design |
| Operating Days per Year | d/a | 365 | Proposed design |
| Process Plant Availability | % | 75 | Proposed design |
| Equipment Capacity Design Factor | % | 25 | Proposed design |
| Design Throughput | tph | 761 | Proposed design |
| Salt Bulk Density | t/m3 | 1.28 | Reported parameter |
| Bond Abrasion Index (Ai, max) | g | 0.07 | Testwork |
| UCS, 75th Percentile | MPa | 28.6 | Testwork |
| ROM Moisture (max) | % | 2 | Reported parameter |
| ROM (Plant Feed) Size F100 | mm | 200 | Proposed design |
| Fines Production (max percent of feed to plant) | % | 10 | Proposed design |
| Product Sodium Chloride (min, dry basis) | % | 95 | Proposed design |
| Product Insolubles (max, dry basis) | % | 5 | Proposed design |
| Product Moisture (max) | % | 2 | Proposed design |
| Product Anti-caking Agent (min) | ppm | 50 | Design specification |
| Product Size P100 | mm | 12.5 | Proposed design |
| Installed Power (processing, conveying, storage, reclaim) | kW | 2,607 | Proposed design |
| Annual Electricity Consumption | MWh | 17,500 | Proposed design |
| YPS Dosage Rate | g/t | 75 | Proposed design |
| YPS Consumption (at 2.5 Mtpa) | tpa | 188 | Proposed design |
| Intermediate Storage Capacity (near mine portals) | t | 11,700 | Proposed design |
| Port Storage Capacity (existing and new) | t | 60,000 | Proposed design |
| Shipment Size Range | 25,000–60,000 t | Proposed design | Not stated |
Project website: https://atlassalt.com/feasibility-study/
Technical qualifications
The report describes proposed storage and shipment facilities; final operating performance is not inferred.
