A processing rate of 25,000 tonnes per day at 92.2% overall gold recovery is proposed based on metallurgical testwork confirming the amenability of mineralization to cyanidation.
Report context
This technical report is dated July 30, 2025, and constitutes an Independent Preliminary Economic Assessment for the Rogue Project, located in Yukon, Canada, on behalf of Snowline Gold Corp. The report was prepared by SRK Consulting (Canada) Inc. The processing sections describe a proposed conventional gold recovery circuit incorporating grinding, gravity recovery, carbon-in-leach recovery, and cyanide detoxification.
Processing route
Primary Crushing
Run-of-mine ore with an estimated 80% passing size of 360 mm will be fed to a primary gyratory crusher. The crusher will reduce the ore to a product with an 80% passing size of 150 mm, which will be conveyed to a covered coarse ore stockpile with an approximate 24-hour live capacity and 75,000 tonne total capacity. A dust collection and control system will capture fugitive dust from transfer points within the crushing circuit.
Grinding
A coarse ore reclaim system will feed a semi-autogenous grinding (SAG) mill operating with a mixed 100 mm and 125 mm diameter forged steel ball charge at 68 to 74% of critical speed. SAG mill discharge will pass through grates with 19 to 32 mm slotted openings and a trommel screen. Trommel oversize will report to a double-deck vibrating screen; material below 10 mm will be transferred to a secondary ball mill, and material above 10 mm will be returned to a pebble crusher.
The ball mill circuit will receive material with an 80% passing size of 10 mm or less. Cyclone underflow at approximately 72% solids will feed the ball mill, which will operate with a 63 to 75 mm diameter forged steel ball charge at 74 to 78% of critical speed. The cyclone overflow target is 28 to 32% solids with a grinding circuit product 80% passing size of 75 microns.
Gravity Concentration
A portion of the cyclone underflow will be fed to high-speed centrifugal concentrators. Gravity concentrate will be directed to an automated high-intensity cyanidation circuit to dissolve gravity-recoverable gold for direct electrowinning in the refinery. Gravity circuit tailings will return to the cyclone feed pumpbox.
Pre-Leach Thickener
Secondary cyclone underflow will flow by gravity to a pre-leach thickener for dewatering to 45% solids. Thickener overflow will provide recycled make-up water to the grinding circuit.
Pre-Aeration, Cyanidation and Carbon-In-Leach Circuit
A single pre-aeration tank will adjust feed slurry to pH 10.5 prior to cyanide addition and control slurry density to 42% solids. Slurry will then feed a single cyanidation tank operated without carbon addition, intended to achieve approximately 80 to 90% dissolution of gold values before the CIL circuit.
Five stages of carbon-in-leach will follow, with in-tank carbon concentration of 10 to 15 g/L. Barren stripped carbon will be introduced into CIL tank #5 and loaded carbon will be removed from CIL tank #1. The outflow from CIL tank #5 will flow by gravity to a carbon safety screen.
Carbon Management and ADR Circuit
Loaded carbon will be rinsed, acid washed with dilute nitric acid, and pressure stripped using the conventional Zadra method at 125°C and 350 kPa. Loaded eluate will be circulated through electrowinning cells. Barren carbon will undergo thermal regeneration and screening before return to the CIL circuit.
Electrowinning and Gold Refinery
Electrowinning cell sludge will be filtered and transferred to a retort to dry the precipitate and capture any potential mercury content prior to refining in an induction furnace. Doré bullion will be shipped as 1,000 oz bars.
Cyanide Destruction Circuit
CIL tailings slurry will be treated with SO₂/air cyanide destruction using sodium metabisulphite in combination with soluble copper and air. Treated solution low in cyanide concentration will be recycled within the process plant.
Water Management Systems
Water management will include reclaim water recycled from the tailings storage facility, internal recycle of process water from the grinding circuit thickener, distribution of fresh water for fire water, and fresh water make-up as required.
Reagents and Consumable Handling
A covered and contained reagent storage area will accommodate steel grinding media, lime, sodium cyanide, flocculant, sodium metabisulphite, copper sulphate, nitric acid, anti-scalant, activated carbon, silica flour, soda ash, sodium nitrate, and borax.
Energy
An estimated energy demand of 30 to 35 MW is associated with the process facility. Energy supply will consider diesel generated power, with further study required on the practicality and financial viability of a power transmission line to site.
Key reported parameters
| Parameter | Value | Basis |
|---|---|---|
| Processing rate | 25,000 tonnes/day | Initial project definition |
| Overall gold recovery | 92.2% | Initial project definition |
| Primary crusher product (P80) | 150 mm | Proposed design |
| Grinding circuit product (P80) | 75 microns | Proposed design target |
| Pre-leach thickener underflow density | 45% solids | Proposed design |
| CIL slurry density | 42% solids w/w | Proposed design |
| CIL carbon concentration | 10 to 15 g/L | Proposed design |
| Pre-aeration target pH | 10.5 | Proposed design |
| Cyanidation tank gold dissolution | 80 to 90% | Proposed design assumption |
| Zadra strip temperature | 125°C | Proposed design |
| Zadra strip pressure | 350 kPa | Proposed design |
| Ball mill ball charge volume | 38% | Proposed design |
| SAG mill ball charge volume | 10% | Proposed design |
| Estimated energy demand | 30 to 35 MW | Preliminary estimate |
Project website: https://www.snowlinegold.com/rogue
Technical qualifications
This technical report constitutes a Preliminary Economic Assessment and is preliminary in nature. Metallurgical testwork has confirmed the amenability of mineralization to cyanidation, supporting the proposed conventional circuit. Equipment sizing and selection will follow as an outcome of basic and detailed engineering. Alternative pebble crushing arrangements are to be studied. Additional study is required to confirm specifics for connected load, duty and demand factor. The practicality and financial viability of a power transmission line to site is subject to further study.
*Source: Rogue Project , 2025 Technical Report, Section 17, Recovery Methods, SRK Consulting (Canada) Inc., July 30, 2025*
