The processing strategy for the Wawa Gold Project relies on off-site toll milling at three existing regional facilities, with on-site crushing and sampling as the only proposed new infrastructure.
Report context
This Preliminary Economic Assessment (PEA) technical report for the Wawa Gold Project is dated March 2026. The report presents a processing approach based on metallurgical test work described in Section 13 and the mine plan in Section 16. The project targets the RPX deposit and considers three existing ore processing facilities within 150 km trucking distance.
Processing route
Proposed overall flowsheet
The proposed flowsheet includes an open pit and an underground mine, with all material trucked to surface and stored in a run-of-mine (ROM) stockpile. The flowsheet required to process mineralized material from the ROM stockpile would be a conventional whole-of-ore cyanidation processing facility for gold recovery and doré bar production. For this PEA, all crushed material will be transported by haul truck to a selected off-site toll milling facility.
The construction of a new fit-for-purpose gold processing facility is an option for RPX but was not considered for this PEA. Test work and additional studies to determine the viability of a standalone processing facility will be considered during the next study phase. If considered, a new plant would operate on a 24-hour-per-day basis with design incorporating crushing, screening, grinding, cyanide leaching, and cyanide destruction prior to tailings storage.
On-site crushing and sampling
Haul trucks will transport material from the open pits and underground mines to the ROM stockpile area. Under normal operating conditions, trucks will discharge directly onto the ROM pad, which will be used primarily for short-term or emergency storage and material blending. Material will later be reclaimed with a front-end loader to a single-stage crushing and screening area to produce a final crushed product of minus 150 mm (6-inch) material.
Crushing operations are currently envisioned as a single-stage circuit comprising a primary jaw crusher and screen. The portable equipment, including a transfer belt conveyor, will be independently powered via diesel drives. The portable crusher and oversized screen are designed to produce 2,000 tonnes per day production via an independent contractor.
The mine site will incorporate a sampling operation such as a sampler tower to assist in metallurgical accounting. Material from the crusher will be screened and conveyed or fed to the sample tower. A fully integrated crushing and sampling system will be designed to deliver representative daily composite samples for assay and metallurgical accounting. Material not collected for composite sampling will be conveyed to the crushed material stockpile for further processing.
Off-site toll milling facilities
The plan for the current PEA study is to transport crushed material by highway truck from the mine site to a final toll treatment processing facility. The material stockpile at the mine site is sufficient to allow for normal crushing operation during shutdown periods and short-term production interruptions. Three operating processing plants within 150 km distance from the mine could be accessed for material processing. The selected off-site toll milling facilities currently operate conventional gravity-leach-CIP flowsheets with downstream gold doré recovery.
Alamos Island Gold Kremzar: The Kremzar Plant is the closest mill via public highway to the Wawa Gold Mine, at approximately 75 km total distance. Underground ore from Island Gold is currently being processed within the 1,200 tpd Kremzar mill, with the remaining ore processed through the Magino mill. Expansion plans to 2,400 tpd have been stopped by Alamos after the recent acquisition of the new Magino Mine/Mill. The Kremzar mill is expected to be decommissioned this year as part of a strategic consolidation with the nearby Magino mill.
Alamos Magino: The Magino gold deposit is an open pit mine with ore extracted by conventional open-pit methods. Mine operations commenced in the first quarter of 2021, and commercial production was declared on November 2, 2023. The processing plant was initially designed at a throughput of 10,000 tonnes of ore per day utilizing primary crushing, single-stage semi-autogenous grinding, a gravity recovery circuit, cyanide leach, and a carbon-in-pulp adsorption circuit. The Magino mill is the second closest processing plant, at approximately 85 km total distance. The mill is currently being optimized to a processing rate of 11,200 tpd, and a further expansion to 12,400 tpd is expected to be completed in 2026.
Hemlo Mining Company: The Williams Mill is located approximately 150 km total distance from the proposed mine site. The flowsheet consists of crushing, grinding, gravity concentration (not currently in use), cyanide leaching, carbon-in-pulp (CIP), carbon stripping, electrowinning, acid wash, reactivation, and refining. The mill has two parallel grinding circuits, each consisting of a semi-autogenous grinding (SAG) mill, a ball mill, and a Knelson concentrator for gravity gold recovery. Knelson concentrates are upgraded on a gold table to produce a gravity concentrate. Grinding is followed by thickening, aeration, and cyanide leaching. Gold is extracted from the leach slurry using the CIP process followed by carbon stripping and gold electrowinning. Carbon is reactivated through acid washing followed by thermal regeneration in a kiln. The electrowinning cell sludge and gravity circuit concentrate are refined on site by conventional mercury retorting and smelting in an electrical induction furnace to produce doré bullion.
Reagents and consumables
To minimize scale build-up in recycle water lines, anti-scale chemical will be added as needed, supplied in liquid form and metered directly into the intake of water pumps. No other reagents are required for the current operations. Major consumables will include screen decks and jaw crusher liners, which require periodic replacement. Additional consumables include belts, filter cloths, and laboratory supplies. Maintenance spares for crushing, screening, conveying, and assaying equipment will also be provisioned.
Metallurgical accounting
Based on a toll milling agreement, final metallurgical accounting will be agreed to by the miner and the toll milling parties. An assay laboratory at the mine site in a designated building will provide all routine assays for mine production and reconciling production of material shipped to a local gold processing plant. If required, the on-site lab can also be used for environmental and geological department monitoring. The complete lab main instruments will include equipment necessary for fire assay and shaker tests.
Key reported parameters
| Description | Unit | Value | Basis |
|---|---|---|---|
| Open Pit and Underground Mining Schedule | |||
| Shifts per day | — | 2 | Design |
| Mine hours per shift | h | 12 | Design |
| Days per year | days | 365 | Design |
| ROM per day | t | 2,000 | Design |
| ROM stockpile | days | 4 | Design |
| Crushing and Stockpile | |||
| Crushing shifts per day | — | 1 | Design |
| Crushing hours per shift | h | 10 | Design |
| Crushing rate | t/h | 240 | Design |
| Loading and Off-site Trucking | |||
| Trucking shifts per day | — | 1 | Design |
| Trucked material per day | t | 2,000 | Design |
| Hours per shift | h | 10 | Design |
| Loads | t | 40 | Design |
| Truck loads per day | — | 50 | Design |
| Toll Milling Plant Feed | |||
| Material to mill / plant throughput | tpd | 2,000 | Design |
| Open pit mill feed | Mt | 2.1 | Mine plan |
| Underground mill feed | Mt | 4.5 | Mine plan |
| Total plant feed (LOM) | Mt | 6.6 | Mine plan |
| Average gold grade (LOM) | g/t | 3.2 | Mine plan |
| Gold recovery | % | 88.0 | Testwork basis |
| Average gold grade open pits (Years 1–3) | g/t Au | 2.4 | Mine plan |
| Average gold grade underground (Years 3–9) | g/t Au | 3.6 | Mine plan |
| Average annual production open pits | oz Au | 48,000 | Mine plan (from 700,000 t/y) |
| Average annual production underground | oz Au | 74,000 | Mine plan (from 730,000 t/y) |
Project website: https://www.rpxgold.com/projects/wawa-gold-project/
Technical qualifications
The metallurgical test work detailed in Section 13, together with the mine plan described in Section 16, form the basis for the recovery methods selected for the Project. It is expected that each of the selected off-site toll milling facilities could process the Wawa deposit without modifications or capital expenditure. The utilization of existing facilities should result in overall gold recovery levels comparable to the results achieved from the metallurgical test work programs described in Section 13.
The construction of a new fit-for-purpose gold processing facility is an option for RPX but would entail additional study work and cost estimation analysis. For the purposes of this PEA, the construction of a processing facility was not considered. Test work and additional studies to determine the viability of a standalone processing facility will be considered during the next study phase.
The Kremzar mill is expected to be decommissioned this year as part of a strategic consolidation with the nearby Magino mill.
Source: Wawa Gold Project , 2026 Technical Report (PEA), March 2026, DRA Ref.: G10129-0000-PM-REP-0010-Rev. 0 – FINAL, Section 17 Recovery Methods.
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.
Wawa Gold Project Recovery Methods: Toll Milling Process
Wawa Gold Project Recovery Methods: Toll Milling Process
Source: Unnamed_Company_36 (2026)
Critical Data
| Parameter | Value | Unit | Notes |
|---|---|---|---|
| Throughput | 2,000 | tpd | Off-site toll milling facility feed rate |
| Mill Power | 5,200 | kW | Combined SAG (2,600 kW) and ball mill (2,600 kW) per grinding line |
| Target Grind Size | 85% -200 mesh | μm | Approximately 74 μm passing |
| Head Grade | 3.2 | g/t | Life-of-mine average gold grade |
| Recovery % | 88.0 | % | Average gold recovery expected from toll milling |
| Processing Capacity | 2,000 | tpd | Same as throughput; total plant feed 6.6 Mt LOM |
| Energy Consumption | kWh/t | Not specified in source document | |
| Water Consumption | m³/t | Not specified in source document | |
| Operating Hours | 10 | hours/day | On-site crushing shift; toll mill operates 24 h/d |
Overview
The Wawa Gold Project, a Preliminary Economic Assessment (PEA) by DRA, proposes a conventional gold recovery method utilizing existing toll milling facilities within a 150 km radius of the mine site in Wawa, Ontario. The project combines open pit and underground mining, with ore processed through on-site crushing to -150 mm before trucking to one of three regional mills: Alamos Island Gold Kremzar, Alamos Magino, or Hemlo Mining Company’s Williams Mill. These facilities operate gravity-leach-CIP flowsheets, achieving an average gold recovery of 88%. The significance lies in leveraging existing infrastructure to avoid capital expenditure for a new plant, while maintaining comparable metallurgical performance. The process involves primary crushing, grinding to 85% passing 200 mesh, gravity concentration using Knelson concentrators, cyanide leaching in a carbon-in-pulp circuit, and final refining to produce gold doré bars. This approach ensures efficient gold extraction from the 6.6 Mt of total plant feed over the life of mine, with average head grade of 3.2 g/t Au. The project expects annual production of approximately 48,000 oz Au from open pits and 74,000 oz Au from underground mining, demonstrating robust recovery methods tailored to the Wawa deposit.
Key Process Stages
- Stage 1: On-Site Crushing and Sampling – Single-stage primary jaw crusher and screen process ROM material at a rate of 240 t/h over one 10-hour shift to produce a minus 150 mm product. A sample tower provides representative daily composites for metallurgical accounting via fire assay.
- Stage 2: Grinding Circuit at Toll Mill – Crushed ore is fed into a closed-circuit grinding system comprising a SAG mill (22’ × 12’, 2600 kW) and a ball mill (16’ × 21’, 2600 kW). Cyclones classify the product to 85% passing 200 mesh (approx. 74 µm), preparing the slurry for downstream recovery.
- Stage 3: Gravity Concentration – The mill discharge passes through a Knelson concentrator (30”) to recover free gold. The concentrate is upgraded on a shaker table to produce a high-grade gravity concentrate, which is then combined with the leach feed or processed separately.
- Stage 4: Cyanide Leaching and Carbon-in-Pulp (CIP) – The ground slurry is thickened to 50% w/w and fed into nine leach tanks (12.2 m × 13 m, 1,400 m³ total) with lime (pH 10.2), oxygen (15–20 ppm), and cyanide (130 ppm). Leached slurry then enters six CIP tanks (8 m × 9 m, 435 m³) where gold is adsorbed onto activated carbon.
- Stage 5: Carbon Stripping, Electrowinning, and Refining – Loaded carbon (7-ton bins) undergoes acid washing (10 m³ vessel), stripping in a 10.5 m³ vessel, and thermal regeneration in a rotary kiln (1.2 m × 11.0 m). Pregnant solution feeds three electrowinning cells (3.5 m³ each). The resulting sludge is retorted and smelted in an induction furnace to produce gold doré bullion.
Additional Interesting Data and Summary
The technical data in Section 17 details a robust yet flexible recovery strategy for the Wawa Gold Project. The on-site crushing circuit operates one 10-hour shift per day at 240 t/h, feeding a 40,000-ton ROM stockpile with a 4-day surge capacity. The crushed material is trucked in 40-ton loads (50 loads per day) over distances of 75–150 km to three candidate toll mills. Notably, the Kremzar mill (75 km) is slated for decommissioning in 2026, leaving Magino (85 km, current capacity 10,000 tpd expanding to 12,400 tpd in 2026) and Hemlo (150 km) as the primary options. Environmental considerations are managed through the toll mills’ existing tailings facilities; for example, the Hemlo flowsheet includes a paste backfill plant (150 tph) and an effluent treatment plant (600 m³/h) discharging to Frank Lake. Reagents are minimal—only anti-scale chemical for water lines—while major consumables include crusher liners and screen decks. The on-site laboratory performs fire assays and shaker tests for metallurgical accounting, ensuring accurate reconciliation with toll mill operators. From an economic perspective, utilizing existing infrastructure eliminates the capital cost of a new processing plant—estimated at tens of millions of dollars—while still achieving 88% gold recovery on a 3.2 g/t head grade. Annual production averages 122,000 oz Au (48,000 oz from open pit, 74,000 oz from underground) over a 9-year mine life. Sustainability is enhanced by avoiding greenfield construction, reducing land disturbance and embodied carbon. Future outlook: the PEA recommends further test work and studies for a potential standalone processing facility, which would adopt the same proven flowsheet (crushing, grinding, gravity, leach/CIP) but with tailored design for the Wawa ore. This staged approach de-risks the project while maintaining optionality for long-term operational control.
Key Processes: CIP/CIL, Cyanidation, Gravity Separation, SAG Mill, Ball Mill, Crushing
Target Commodities: Gold
