Source: GOLD X2 MINING INC (2026)
Website: https://goldx2.com/moss-gold-project/
Critical Data
| Parameter | Value | Unit | Notes |
|---|---|---|---|
| Throughput | 11 | Mtpa | Nominal fresh rock processing capacity |
| Target Grind Size | 55 | μm | Primary grind P80; concentrate regrind to 15 μm |
| Concentrate Regrind Size | 15 | μm | P80 for flotation concentrate prior to CIL |
| Residence Time (Concentrate CIL) | 48 | hours | Cyanide leaching and carbon adsorption duration for concentrate |
| Residence Time (Tailings CIL) | 24 | hours | Cyanide leaching for combined flotation and concentrate CIL tailings |
| WAD Cyanide Limit | <1 | ppm | Weak acid dissociable cyanide after destruction using SO₂/air process |
Overview
The Moss Gold Project, located near Thunder Bay, Ontario, is a significant gold development owned and operated by Gold X2 Mining Inc. The project’s Preliminary Economic Assessment (PEA), effective January 26, 2026, outlines a robust gold recovery flowsheet based on conventional flotation and cyanide leaching via carbon-in-leach (CIL) technology. Designed to process 11 million tonnes per annum (Mtpa) of fresh rock, the plant will produce doré bars through a series of integrated unit operations. The significance of this project lies in its ability to achieve high gold recoveries by combining flotation to concentrate the gold-bearing material and CIL for intensive leaching and adsorption. The process begins with two-stage crushing and semi-autogenous grinding (SAG) and ball mills, reducing ore to a target P80 of 55 µm. Rougher flotation then upgrades the feed, with the concentrate reground to 15 µm before entering a dedicated CIL circuit with 48 hours residence time. Tailings from flotation and concentrate CIL undergo a separate 24-hour CIL circuit, ensuring maximum gold extraction. Cyanide destruction using the SO₂/air process reduces weak acid dissociable (WAD) cyanide to below 1 ppm, meeting strict environmental standards. This integrated approach positions the Moss Gold Project as a technically sound and environmentally responsible gold recovery operation, supporting Ontario’s mining sector.
Key Process Stages
- Stage 1: Comminution – Two-stage crushing followed by a SAG mill and ball mills in closed circuit with hydrocyclones produces a final grind size of P80 55 µm, ensuring optimal liberation for flotation.
- Stage 2: Rougher Flotation – The ground slurry undergoes rougher flotation to concentrate gold-bearing sulfides, rejecting barren gangue and reducing the mass flow to downstream leaching circuits.
- Stage 3: Concentrate Regrind – Flotation concentrate is reground to a target P80 of 15 µm using an IsaMill or similar technology, increasing surface area for efficient cyanide leaching.
- Stage 4: Concentrate Carbon-in-Leach (CIL) – The reground concentrate is thickened and then leached with cyanide in a CIL circuit with 48 hours residence time. Gold is adsorbed onto activated carbon, followed by carbon elution via a 6-tonne split pressure Zadra circuit, electrowinning, and smelting to produce doré.
- Stage 5: Tailings CIL and Cyanide Destruction – Combined flotation tailings and concentrate CIL tailings undergo a secondary 24-hour CIL circuit for residual gold recovery. The final tailings are treated in a cyanide destruction circuit using the SO₂/air process to reduce WAD cyanide below 1 ppm before pumping to a tailings storage facility.
Additional Interesting Data and Summary
The remaining technical data for the Moss Gold Project’s recovery methods emphasizes a holistic and environmentally conscious design. The process plant incorporates a 6-tonne split pressure Zadra circuit for carbon elution, ensuring efficient gold stripping from loaded carbon. Carbon handling and regeneration circuits extend carbon life, reducing operating costs. Electrowinning and smelting convert the gold-silver sludge into high-purity doré bars. A critical environmental feature is the cyanide destruction circuit, which employs the SO₂/air process to lower WAD cyanide to less than 1 ppm, exceeding typical regulatory requirements and mitigating long-term tailings management risks. The plant layout prioritizes operator safety and maintenance access, with sufficient automation to minimize continuous operator interface while allowing manual override. Equipment selection focuses on reliability and ease of maintenance, supporting the 11 Mtpa nominal throughput. Although specific energy and water consumption figures are not provided in the PEA, the flowsheet is designed with closed-loop water systems (potable, raw, gland seal, and process water) to minimize freshwater intake. The air and oxygen circuits support the leaching and cyanide destruction processes. Economically, this PEA-stage project demonstrates a technically robust gold recovery approach that leverages proven unit operations—flotation and CIL—adapted to the Moss deposit’s mineralogy. The combination of a coarse primary grind (55 µm) with fine regrind (15 µm) optimizes both liberation and leaching kinetics. Future outlook includes potential process optimization through piloting and detailed engineering, aiming to maximize recovery rates beyond the baseline design. The significance of this facility lies in its ability to process a large tonnage with low environmental impact, positioning Gold X2 Mining Inc. as a responsible developer in Ontario’s Thunder Bay mining district. Sustainability initiatives are embedded in the flowsheet, particularly the cyanide destruction step and water recycling, aligning with industry best practices for green mining.
Key Processes: Flotation, CIP/CIL, Cyanidation, SAG Mill, Ball Mill, Crushing
Target Commodities: Gold
Technical report and processing history
The following archived source profiles have been consolidated here to preserve the project’s processing history and study context.
Moss Gold Project — 2026 Preliminary Economic Assessment
Moss Gold Project — 2026 Preliminary Economic Assessment
| Company | GMS |
| Date | 2026 |
| Region | Unknown |
| Commodities | Gold |
| Mine Type | Open Pit |
| Throughput | 11 Mtpa (30,140 t/d) |
| Status | Development |
Executive Summary
This Preliminary Economic Assessment NI 43-101 Technical Report outlines the proposed process plant design for the Moss Gold Project. The facility is designed to treat 11 million tonnes per annum (Mtpa) of fresh rock to produce doré. The flowsheet is based on metallurgical testwork, industry standards, and conventional unit operations, focusing on a flotation and leaching circuit to maximize gold recovery while minimizing operating costs.
The process plant includes a two-stage crushing circuit feeding a comminution section consisting of a semi-autogenous (SAG) mill and ball mills with hydrocyclones. The ground material undergoes rougher flotation, with the concentrate undergoing regrind before entering a Carbon-in-Leach (CIL) circuit. Flotation tailings are also treated in a separate CIL circuit. The design targets an overall gold recovery of 91.9% with a head grade of 0.89 g/t.
Final gold recovery involves carbon elution via a pressure Zadra circuit, electrowinning, and smelting. The plant includes a cyanide destruction circuit using the SO2/Air process to treat CIL tailings before disposal to a tailings storage facility. The design emphasizes reliability, maintainability, and process control to minimize operator intervention while ensuring safety and environmental compliance.
Reports
Website: https://goldx2.com/moss-gold-project/
Report Date: 2026
Region: Unknown
Project Status: Development
Commodity: Gold
Throughput: 11 Mtpa (30,140 t/d)
Mine Life:
Mine Type: Open Pit
Ore type:
Moss Lake Deposit — 43-101 Technical Report
This report presents the proposed process plant design for the Moss Lake gold deposit based on conventional gravity and carbon-in-leach technology.
Report context
This technical report and mineral resource estimate for the Moss Lake Deposit was prepared in support of a 43-101 disclosure. The processing chapter (Section 17 – Recovery Methods) describes a proposed plant design intended to treat 14.0 million tonnes per annum of mineralized material using established Gravity/CIL technology.
Processing route
Crushing and stockpiling
The primary crushing plant is designed to treat 2,131 tonnes per hour for 18 hours per day. The run-of-mine (ROM) bin has a capacity of 200 m³ and is equipped with a 700 x 700 mm static grizzly. Oversize material will be broken by a mechanical rock breaker. An apron feeder withdraws material at a controlled rate onto a vibrating grizzly feeder; undersize at -150 mm joins the crusher discharge conveyor. The single-stage gyratory cone crusher operates at a closed side setting of 150 mm to produce 80% passing 150 mm. Crushed product is conveyed to a 15,000-tonne live conical stockpile. Dust suppression uses conveyor skirting and atomized water sprays.
Milling and classification
Reclaim from the stockpile is via long variable speed pan feeders, each sized for 550 tph. The milling circuit comprises a grate discharge SAG mill and an overflow discharge ball mill, capable of treating 1,700 tph of hard rock. The SAG mill operates at a ball load of 8% by volume up to a maximum 15% and has a variable speed drive. A pebble crusher with a closed side setting of 12 mm reduces pebbles from the SAG mill trommel (12 mm slotted apertures) before recirculation. An over-band electro-magnet and metal detector protect the pebble crusher.
The SAG mill discharge at P80 of 750 μm and 65% solids by weight passes over the trommel screen. Trommel undersize combines with ball mill discharge in a cyclone feed sump, diluted to 58-60% solids, and pumped to a hydrocyclone cluster. Cyclone overflow at P80 of 106 μm at approximately 40% solids by weight gravitates to a linear screen for trash removal. Underflow returns to the ball mill. A facility to bleed part of the cyclone underflow to the SAG mill is provided. A bypass conveyor allows material to feed directly to the ball mill during SAG mill maintenance.
Lime is dosed into the SAG mill with an option to bypass to the ball mill and additional lime added to the pre-leach tank as required.
Gravity recovery and intensive cyanidation
A portion of the cyclone underflow is bled to a scalping screen to remove +2 mm material. Screen undersize at approximately 47% solids feeds a centrifugal concentrator for free gold recovery. Concentrates are discharged into a Gekko ILR feed cone and leached batch-wise for 14-16 hours using an In-line Leach Reactor. Pregnant solution from the gravity circuit is pumped to a dedicated electrowinning cell with stainless steel wire mesh cathodes. The gravity tailings gravitate to the cyclone feed sump.
Pre-leach and carbon-in-leach (CIL)
Cyclone overflow after trash removal gravitates to a pre-leach/CIL circuit comprising ten tanks: two pre-leach tanks and six CIL tanks. Total effective residence time is 48 hours. Slurry flows through interconnecting launders. Each CIL tank is equipped with an inter-stage wedge wire cylindrical pumping screen to prevent carbon migration. Cyanide is dosed into the second pre-leach tank via a ring main; an automatic cyanide analyzer controls addition. Loaded carbon from CIL Tank 1 (or Tank 2 if Tank 1 is on bypass) is pumped to a loaded carbon screen; underflow returns to the CIL tank. Recessed impeller vertical spindle pumps transfer carbon upstream at intermittent intervals between CIL Tanks 2 to 6. Eluted or regenerated carbon is added to the last CIL tank.
Detoxification
CIL tailings slurry passes through a carbon safety screen to recover escaped carbon. Screen underflow gravitates to the detoxification circuit of three tanks. Free cyanide and weakly bound metal cyanide complexes are oxidized by addition of sulphur dioxide (supplied as sodium metabisulphite) and oxygen. A copper catalyst at approximately 50 mg/l is added as copper sulphate solution. Lime slurry neutralizes acid formed during the reaction.
Tailings disposal and water return
Slurry from the third detoxification tank gravitates to a final tails sump and is pumped to the tailings disposal and storage facilities. Process water from the tailings dam returns to a return water pond and is pumped via pontoon pumps to a return water tank, then to the plant process water tank.
Carbon regeneration and gold recovery
Loaded carbon is acid washed in a 2-tonne batch cone using dilute hydrochloric acid (~3% HCl) at 2 bed volumes per hour for 1 hour, then rinsed. Elution uses the pressurized Zadra method with cyanide-caustic solution at 2 bed volumes per hour, heated to 120°C via primary and secondary heat exchangers using thermic oil. The column operates at 300 to 350 kPa. The elution cycle runs approximately 14 hours. Pregnant eluate is directed to double sludging electrowinning cells. Spent electrolyte returns to the eluant tank in closed circuit.
Carbon is regenerated in an electric fired inclined kiln at 600 kg/hr, quenched, and screened before returning to the CIL circuit. A virgin carbon conditioning facility removes fines.
Gold smelting
Gold sludge from electrowinning is dried in calcining ovens at 800°C. Dried sludge is mixed with fluxes and smelted in an induction furnace at 1,200 to 1,400°C. Molten gold is poured into cascading bullion moulds; slag collects in a separate crucible. Gold bars are cleaned, stamped, and stored prior to dispatch.
Consumables and services
Grinding media: 100 mm balls for SAG mill and 65 mm balls for ball mill. Sodium cyanide delivered in 1-tonne bulk bags, dissolved batch-wise to 25% by weight. Caustic soda delivered in 25 kg bags, dissolved to 20% by weight. Quicklime delivered in 1-tonne bags, slaked in a detention lime slaker to produce lime slurry. Sodium metabisulphite delivered in 1-tonne bulk bags, dissolved to 25% by weight. Copper sulphate delivered in 25 kg bags on pallets, dissolved to 15% by weight. Carbon delivered in 500 kg bulk bags. Hydrochloric acid delivered in 290 kg (210 litre) drums at 33% concentration.
Compressed air: two compressors (one duty, one standby) provide 2,000 Nm³/hr at 750 kPa for process uses plus a dedicated instrument air compressor.
Water services: a pontoon with centrifugal pumps draws raw water from a storage facility. Return water from tailings and raw water top-up constitute process water. Dedicated pumps supply mill cooling, gravity concentrator fluidising water, dust suppression, reagent make-up, potable water, gland water, and fire water systems. Fire water includes electric and diesel driven pumps plus a jockey pump.
Key reported parameters
| Parameter | Value | Unit | Basis |
|---|---|---|---|
| Plant throughput | 14.0 | million tonnes per annum | Proposed design |
| Primary crushing rate | 2,131 | tonnes per hour | Proposed design |
| Primary crusher product size | 80% passing 150 | mm | Proposed design |
| Stockpile live capacity | 15,000 | tonnes | Proposed design |
| Milling rate (hard rock) | 1,700 | tonnes per hour | Proposed design |
| SAG mill ball load | 8% to maximum 15% | % by volume | Proposed design |
| SAG mill discharge P80 | 750 | μm | Proposed design |
| SAG mill discharge density | 65 | % solids by weight | Proposed design |
| Cyclone feed density | 58-60 | % solids by weight | Proposed design |
| Cyclone overflow P80 | 106 | μm | Proposed design |
| Cyclone overflow density | ~40 | % solids by weight | Proposed design |
| Gravity feed density | ~47 | % solids by weight | Proposed design |
| Gravity leach residence time | 14-16 | hours | Proposed design |
| Pre-leach/CIL tanks | 2 pre-leach + 6 CIL | tanks | Proposed design |
| CIL total residence time | 48 | hours | Proposed design |
| Detoxification tanks | 3 | tanks | Proposed design |
| Copper catalyst concentration | ~50 | mg/l | Proposed design |
| Acid wash rate | 2 | bed volumes per hour | Proposed design |
| Acid wash duration | 1 | hour | Proposed design |
| Elution flow rate | 2 | bed volumes per hour | Proposed design |
| Elution temperature | 120 | °C | Proposed design |
| Elution pressure | 300 to 350 | kPa | Proposed design |
| Elution cycle duration | ~14 | hours | Proposed design |
| Carbon regeneration rate | 600 | kg/hr | Proposed design |
| Calcining oven temperature | 800 | °C | Proposed design |
| Smelting furnace temperature | 1,200 to 1,400 | °C | Proposed design |
| Compressed air capacity | 2,000 | Nm³/hr | Proposed design |
| Compressed air pressure | 750 | kPa | Proposed design |
| Cyanide solution concentration | 25 | % by weight | Proposed design |
| Caustic soda solution concentration | 20 | % by weight | Proposed design |
| Sodium metabisulphite concentration | 25 | % by weight | Proposed design |
| Copper sulphate concentration | 15 | % by weight | Proposed design |
| Hydrochloric acid concentration | 33 | % | Proposed design |
Project website: https://www.newswire.ca/news-releases/moss-lake-announces-preliminary-economic-analysis-results-512756691.html
Technical qualifications
This report presents a proposed process plant design only. No historical operating data from a Moss Lake plant is presented. The report notes that laboratory tests on some mineralized material samples displayed high cyanide consumptions. No testwork results, metallurgical recoveries, or throughput performance data from pilot-scale or demonstration-scale operations are provided. The design basis and parameters described are those selected for the proposed plant and do not represent actual operating data.
Source: 43-101 Technical Report and Mineral Resource Estimate – Moss Lake Deposit, Section 17 – Recovery Methods, document dated as referenced in the original report.
