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
