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*
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.
Inside Snowline Gold's Rogue Project: A Deep Dive into the 25,000 TPD Gold Processing Circuit
Overview
Nestled in the mineral-rich terrain of Canada’s Yukon Territory, the Rogue Project represents a significant and highly anticipated development in the North American gold mining landscape. Operated by Snowline Gold Corp., a Vancouver-based exploration and development company, this advanced-stage project is poised to become a major producer in a region renowned for its vast mineral potential. Located in the often-challenging but prospectively rewarding Yukon, the project is the focus of a comprehensive Preliminary Economic Assessment (PEA) that outlines a robust, modern mineral processing operation. The primary commodity of interest is gold, with the metallurgical testwork confirming the ore’s strong amenability to conventional cyanidation processes. The proposed facility is designed for a substantial throughput of 25,000 tonnes per day (tpd), targeting an impressive overall gold recovery rate of 92.2%. This project is not just another mine; it is a testament to modern mining engineering, designed with efficiency, recovery optimization, and environmental stewardship at its core. The development of the Rogue Project is a critical step for Snowline Gold Corp. as it advances from an exploration company to a potential producer, highlighting the economic significance and technical viability of Yukon’s gold resources.
Key Process Stages
The Rogue Project’s processing circuit is a classic example of a modern, integrated gold recovery plant, designed to handle a massive throughput efficiently. It incorporates best practices in comminution, concentration, and leaching to maximize gold extraction from the ore. The flow sheet is a detailed sequence of unit operations, each critical to the overall success of the metallurgical process, from the moment run-of-mine (RoM) ore is delivered to the primary crusher until doré gold bars are poured for shipment.
- Stage 1: Primary Crushing – RoM ore with a top size of 80% passing 360 mm (P80) is fed by haul trucks into a primary gyratory crusher. The crusher reduces the ore to a P80 of 150 mm (6 inches). The crushed product is conveyed to a covered coarse ore stockpile with a 75,000-tonne total capacity, providing a crucial 72-hour buffer. The circuit includes dust collection systems, belt magnets for scrap metal removal, and belt weigh scales for accurate tonnage tracking.
- Stage 2: Grinding (SAG and Ball Mill) – Reclaimed crushed ore is fed into a Semi-Autogenous Grinding (SAG) mill operating at 68-74% of critical speed with a 100/125 mm forged steel ball charge. The SAG mill discharge is classified by a trommel and vibrating screens; +10 mm pebbles are recirculated through a pebble crusher. The sub-10 mm material is pumped to a cyclopack cluster. The cyclone underflow (72% solids) feeds a secondary ball mill charged with 63-75 mm balls, operating at 74-78% of critical speed. The circuit is closed with cyclones to achieve a final grind target of P80 75 microns in the overflow.
- Stage 3: Gravity Concentration & Intensive Leach – A portion of the ball mill discharge is diverted to self-cleaning centrifugal concentrators to recover any coarse, free-milling Gravity-Recoverable Gold (GRG). The high-grade gravity concentrate is not smelted directly but is instead fed to an automated, high-intensity cyanidation circuit. This step dissolves the gold for direct electrowinning, providing early gold recovery and a valuable sample point for metallurgical accounting.
- Stage 4: Pre-Leach Thickening & CIL Circuit – The main ore stream (cyclone overflow) is thickened in a pre-leach thickener to 45% solids. Lime is added in a pre-aeration tank to achieve a pH of 10.5 and pre-oxidize mineral surfaces. Slurry then enters a single cyanidation tank (without carbon) for initial gold dissolution, followed by a five-stage Carbon-In-Leach (CIL) circuit. Each CIL tank maintains a carbon concentration of 10-15 g/L, with carbon moving counter-current to the slurry flow for efficient gold adsorption.
- Stage 5: Carbon Management, Elution & Refining – Loaded carbon from the first CIL tank is acid-washed, pressure-stripped (Zadra process) at 125°C, and thermally regenerated. The gold-rich eluate is processed in an electrowinning cell to produce a gold-rich sludge. This sludge is filtered, and the cake is retorted to remove mercury before being smelted in an induction furnace with fluxes (silica flour, soda ash, etc.) to produce 1,000 oz doré bars.
- Stage 6: Cyanide Destruction & Tailings Management – CIL tailings pass through a carbon safety screen and then undergo a copper-catalyzed SO2/air cyanide destruction process using sodium metabisulphite. This critical environmental control step oxidizes free cyanide to less harmful cyanate before the tailings slurry is pumped to the Tailings Storage Facility (TSF). Water is reclaimed from the TSF and recycled back into the process plant.
Critical Data
The following table summarizes the key technical and operational parameters that define the scale and efficiency of the Rogue Project’s processing circuit, as outlined in the PEA.
| Parameter | Value | Unit | Notes |
|---|---|---|---|
| Design Throughput | 25,000 | tpd | Nominal daily processing rate |
| Overall Gold Recovery | 92.2 | % | Target recovery across the entire circuit |
| Primary Crusher Product Size (P80) | 150 | mm | Reduced from a RoM P80 of 360 mm |
| Final Grind Size (P80) | 75 | μm | Target size for leaching, achieved by SAG/Ball Mill circuit |
| Pre-Leach Thickener Density | 45 | % solids | Slurry density after thickening, before leaching |
| CIL Circuit Density | 42 | % solids | Target slurry density in leach tanks |
| Number of CIL Tanks | 5 | – | Five stages of adsorption for high recovery |
| Estimated Energy Demand | 30-35 | MW | Total connected load for the process facility |
Additional Interesting Data and Summary
Beyond the core process stages, the Rogue Project’s PEA reveals a operation designed with a strong emphasis on environmental management, operational flexibility, and long-term sustainability. The estimated energy demand of 30-35 MW is significant, and the PEA notes that further study is required to finalize the power supply strategy. While diesel generation is a baseline option, the viability of connecting to a regional power grid via a transmission line is under consideration, which could substantially reduce the project’s carbon footprint and operating costs. The comprehensive water management system is a cornerstone of the project’s environmental strategy. It relies heavily on the recirculation of water reclaimed from the Tailings Storage Facility (TSF), minimizing freshwater consumption and ensuring that process water is contained and treated, aligning with strict Yukon environmental regulations.
The reagent handling plan underscores a commitment to safety and containment. Sodium cyanide, a key reagent, will be stored in secure, 1,000 kg semi-bulk bags within wooden crates in a covered and contained storage area. Other consumables, from grinding media to flocculants and smelting fluxes, have dedicated, ventilated mixing and distribution systems. From an economic perspective, the 92.2% recovery rate is a robust figure that significantly enhances the project’s economics, ensuring maximum value is extracted from the mined ore. The inclusion of a gravity circuit with intensive leaching is a particularly savvy design choice, as it allows for the rapid recovery of a portion of the gold early in the process, improving cash flow. The Rogue Project exemplifies modern mineral processing: a large-scale, technically sophisticated operation that balances high recovery efficiency with proactive environmental and safety measures. It stands as a promising development for Snowline Gold Corp., the Yukon Territory, and the Canadian mining industry as a whole.
Source: Preliminary Economic Assessment | Project: Independent Preliminary Economic Assessment for the Rogue Project | Date: APR 2025
