Source: Equinox Gold Corp (2026)
Website: https://www.equinoxgold.com/our-mines/greenstone-gold-mine/
Critical Data
| Parameter | Value | Unit | Notes |
|---|---|---|---|
| Throughput | 27,000 | tpd | Nameplate capacity; achieved peak of 24,000 tpd in 2025 |
| Mill Power | 10,500 | kW | Per ball mill; two mills (21,000 kW total) plus HPGR 2 × 2,580 kW |
| Target Grind Size | 90 | µm | P80 for leach circuit feed |
| Head Grade | 1.08 | g/t | 2025 average feed grade for gold |
| Recovery % | 84 | % | 2025 overall gold recovery; improved from 82.1% in 2024 |
| Processing Capacity | 27,000 | tpd | Design nameplate; ramp-up ongoing |
| Energy Consumption | N/A | Not specified in report; power from on-site natural gas turbines | |
| Water Consumption | N/A | Not specified; bulk water from thickener overflow and TMF reclaim | |
| Operating Hours | 24 | hours/day | Continuous operation inferred from process design |
Overview
Equinox Gold Corp. operates the Greenstone gold mine in Ontario, Canada, using a conventional gravity-cyanidation flowsheet with a nameplate capacity of 27,000 tonnes per day (t/d). Construction began in Q4 2021, with commissioning in Q1 2024. First gold was poured on May 22, 2024, and commercial production was reached on November 6, 2024. The plant processes run-of-mine ore through primary and secondary crushing, followed by a high-pressure grinding roll (HPGR) and ball mill comminution circuit. A gravity circuit captures coarse gold, while gravity tailings undergo leaching and carbon-in-pulp (CIP) adsorption. Loaded carbon is stripped via a Pressure Zadra system, and gold is recovered through electrowinning and smelting into doré bars. Cyanide destruction using the SO₂/O₂ process treats CIP tailings before storage in the tailings management facility. In 2025, the plant processed 7,777 kt of ore at an average head grade of 1.08 g/t Au, achieving an 84% gold recovery rate and producing 224,000 ounces of gold. The plant’s performance reflects a successful ramp-up towards nameplate capacity, with a peak daily throughput of 24 kt/d in 2025.
Key Process Stages
- Stage 1: Primary and Secondary Crushing – Run-of-mine ore is fed into a 1.3 m x 1.8 m gyratory crusher (450 kW) to achieve a P80 of 120–160 mm. Oversize screened material is further crushed by an MP1250 cone crusher to a P80 of 50–70 mm. Screen undersize at P80 35 mm is conveyed to a 57 kt crushed ore stockpile providing 16 hours of live storage.
- Stage 2: HPGR and Grinding with Gravity Recovery – Reclaimed ore passes through a 2.2 m x 2.0 m HPGR (2 × 2,580 kW) to produce a P80 of 25 mm. Screen undersize feeds two parallel ball mills (each 6.7 m diameter, 12.2 m EGL, 10,500 kW) in closed circuit with cyclones for a target grind of P80 90 µm. A gravity concentrator per line recovers coarse gold, feeding a single intensive leach reactor; gravity leach tailings return to the mill.
- Stage 3: Pre-Leach Thickening and Cyanidation – Cyclone overflow (P80 90 µm) flows to a 50 m diameter pre-leach thickener where flocculant increases slurry density to 55% solids. The thickened underflow enters a leach circuit comprising one pre-aeration tank and seven agitated leach tanks (each 18.6 m diameter × 23.5 m high, total residence time 30 h). Sodium cyanide and oxygen are added to dissolve gold, with lime maintaining pH 10–11.
- Stage 4: Carbon-in-Pulp – Leached slurry passes through seven CIP tanks (7 m diameter × 12 m high) in a carousel arrangement, each containing 18 tonnes of activated carbon at 50 g/L concentration. Gold cyanide complexes adsorb onto carbon over the counter-current flow. Once daily, loaded carbon (1 batch per tank) is pumped to the strip circuit via a loaded carbon screen; slurry returns to the CIP circuit.
- Stage 5: Carbon Elution, Regeneration, and Cyanide Destruction – Loaded carbon undergoes acid wash (HCl) to remove foulants, then elution in a 12-tonne Pressure Zadra system at 130°C and 450 kPa using a barren solution of 2% NaOH and 0.2% NaCN. Stripped carbon is regenerated in a 750 kg/h natural gas kiln. CIP tailings are treated in two 1,600 m³ agitated tanks via the SO₂/O₂ process (2 h retention, pH 8.5, copper sulphate catalyst) reducing CNWAD to 30 mg/L before pumping to the TMF.
Additional Interesting Data and Summary
The Greenstone process plant employs a comprehensive suite of reagents including sodium cyanide (briquette form, 18-tonne ISO containers), sodium hydroxide (50% liquid, 20-tonne tankers), quicklime (bulk silo, slaked to 23% slurry), flocculant (dry polymer), hydrochloric acid (33% solution, 22-tonne tankers), copper sulphate pentahydrate (1,250 kg bags), and liquid sulphur dioxide (two 80-tonne pressure vessels). Oxygen for leaching and cyanide destruction is supplied by an on-site vacuum-pressure swing-adsorption plant, backed by two liquid oxygen tanks. Power is generated by on-site natural gas turbines. Water supply includes process water (thickener overflow and TMF reclaim), treated water (from effluent treatment plant for strip circuit, ILR, gland seals, and reagent dilution), and potable water for safety showers and admin areas. The cyanide destruction process (SO₂/O₂) ensures environmental compliance by reducing weak acid dissociable cyanide to 30 mg/L. Economically, the mine produced 224,000 oz of gold in 2025, a significant increase from 112,000 oz in 2024, reflecting the ramp-up to nameplate throughput. Sustainability initiatives include reclaim water from the TMF, use of a carbon regeneration kiln to reduce fresh carbon consumption, and a carbon safety screen to capture fine carbon and recover residual gold. Future outlook involves continued optimization to reach consistent 27 kt/d throughput and further improve gold recovery beyond 84%. The facility is a modern, large-scale gold operation with a proven gravity-cyanidation flowsheet, representing a key asset for Equinox Gold Corp. in Ontario’s mining landscape.
Key Processes: CIP/CIL, Cyanidation, Gravity Separation, Ball Mill, Crushing
Target Commodities: Gold, Copper
Technical report and processing history
The following archived source profiles have been consolidated here to preserve the project’s processing history and study context.
Greenstone Property — 2026 Technical Report
Greenstone Property — 2026 Technical Report
| Company | Equinox Gold Corp. |
| Mine | Greenstone Property |
| Date | 2026-03-30 |
| Region | Not Specified |
| Commodities | Gold |
Executive Summary
The Greenstone process plant treats ore via a conventional gravity-cyanidation flowsheet with a nameplate capacity of 27 kt/d. Construction commenced in Q4 2021 and was substantially complete by the end of Q4 2023. Commissioning activities occurred from Q1 2024 through Q3 2024, with ore introduction on April 6, 2024, and the first gold pour achieved on May 22, 2024. Commercial production was officially achieved on November 6, 2024.
Process plant performance over the last two years indicates successful ramp-up to nameplate capacity. In 2024, the plant milled 3,687 kt of ore with an average feed grade of 1.22 g/t Au and achieved 82.1% gold recovery, producing 112 Koz of gold. During 2025, the plant continued to ramp up, achieving a peak production of 24 kt/d, milling 7,777 kt of ore with an average feed grade of 1.08 g/t Au and 84% gold recovery, resulting in 224 Koz of gold produced.
The processing circuit includes primary and secondary crushing, HPGR and ball mill comminution, a gravity circuit with an intensive leach reactor, and a leach-carbon-in-pulp (CIP) circuit. Tailings are treated via a cyanide destruction process prior to storage in the tailings management facility. The plant utilizes an onsite oxygen plant and natural gas turbines for power, with reagents including sodium cyanide, lime, and hydrochloric acid managed on-site.
Website: https://www.equinoxgold.com/our-mines/greenstone-gold-mine/
Report Date: 2026-03-30
Region: Not Specified
Project Status:
Commodity: Gold
Throughput:
Mine Life:
Mine Type:
Ore type:
Technical Analysis of the Greenstone Gold Mine: Advanced Mineral Processing and HPGR Integration
Overview
The Greenstone Gold Mine, situated in the historic Geraldton-Beardmore Greenstone Belt of Northern Ontario, Canada, represents one of the most significant open-pit gold developments in North America. Managed by Greenstone Gold Mines (GGM)—a 100% owned subsidiary of Equinox Gold Corp. following its full acquisition in mid-2024—the project is a revitalization of the historic Hardrock, MacLeod-Cockshutt, and Mosher mines. Located approximately 275 kilometers northeast of Thunder Bay, the mine sits at the strategic junction of Highway 11 and Highway 584, a location that required the massive undertaking of relocating a portion of the Trans-Canada Highway to facilitate the open-pit expansion.
The significance of the Greenstone Mine extends beyond its impressive gold reserves, which are estimated at over 5 million ounces. It serves as a flagship for modern, large-scale mining in a tier-one jurisdiction. The project’s economic impact is substantial, providing long-term employment and infrastructure development in the Greenstone region. From a technical perspective, the mine is a showcase for energy-efficient comminution, utilizing High-Pressure Grinding Rolls (HPGR) technology instead of a traditional Semi-Autogenous Grinding (SAG) circuit. This design choice was driven by the competency and hardness of the Archean-aged ore, ensuring the facility can maintain its massive design throughput of 27,000 tonnes per day (tpd) while optimizing operational costs and energy consumption. As the project moved into commercial production in early 2024, it transitioned from a multi-year construction phase into a premier gold-producing asset, expected to average over 400,000 ounces of gold annually for the first five years of its 15-year initial mine life.
Key Process Stages
The mineral processing plant at Greenstone is designed for maximum availability and metallurgical efficiency. The circuit utilizes a multi-stage comminution approach followed by a conventional gravity-leach-CIP (Carbon-in-Pulp) recovery process. The primary stages include:
- Primary Crushing: Run-of-Mine (ROM) ore is delivered by 227-tonne haul trucks to a large-scale Gyratory Crusher. This stage reduces the ore to a size manageable for the secondary crushing circuit.
- Secondary Crushing: The primary crushed product is further reduced in size through a secondary cone crushing circuit. This stage is critical for preparing a consistent feed for the HPGR units, ensuring that the feed size distribution is optimized for the rolls.
- High-Pressure Grinding Rolls (HPGR): Instead of a SAG mill, Greenstone employs two parallel HPGR units. This tertiary crushing/grinding stage uses high pressure to create micro-fractures in the ore particles, which significantly reduces the energy required in the subsequent ball milling stage.
- Ball Milling and Classification: The HPGR product is fed into two parallel Ball Mills operating in a closed circuit with hydrocyclones. The target grind size is approximately 80% passing 75 microns, ensuring adequate liberation of gold particles from the host silicate and sulfide minerals.
- Gravity Recovery: A portion of the cyclone underflow is diverted to a gravity concentration circuit. Centrifugal concentrators (such as Knelson or Falcon units) are used to recover coarse free gold, which is then treated in an intensive cyanidation reactor (e.g., Acacia or Gekko) to produce high-grade gold solution.
- Pre-Leach Thickening: The cyclone overflow is thickened to increase the solids concentration to approximately 50%, which optimizes the residence time and chemical concentration in the leaching circuit.
- Leaching and Adsorption (CIP): The thickened slurry enters a series of leach tanks where sodium cyanide is added to dissolve the gold. Following leaching, the slurry moves through a Carbon-in-Pulp (CIP) circuit where gold is adsorbed onto activated carbon.
- ADR and Refinery: The gold-bearing carbon is processed in an Adsorption, Desorption, and Recovery (ADR) plant. This involves elution (stripping the gold from the carbon), electrowinning to plate the gold onto cathodes, and finally smelting in an induction furnace to produce gold doré bars.
Critical Data
The following table outlines the key technical parameters and performance metrics for the Greenstone Gold Mine processing plant at steady-state operation.
| Parameter | Value | Unit |
|---|---|---|
| Design Throughput | 27,000 | Tonnes per Day (tpd) |
| Annual Ore Processed | 9,855,000 | Tonnes per Annum (tpa) |
| Average Head Grade (LOM) | 1.27 | Grams per Tonne (g/t Au) |
| Target Grind Size (P80) | 75 | Microns (µm) |
| Estimated Gold Recovery | 90.5 – 91.2 | Percent (%) |
| Gravity Recovery Component | 25 – 30 | Percent (%) |
| Ball Mill Power (Installed) | ~14,000 | Kilowatts (kW) |
| HPGR Motor Power | ~3,700 (per unit) | Kilowatts (kW) |
| Leach Residence Time | 30 – 36 | Hours |
Technical Details and Sustainability
One of the most defining technical features of the Greenstone Gold Mine is the implementation of HPGR technology. Traditional gold processing in Canada often relies on SAG mills, but the ore at Greenstone is characterized by high competency and a relatively high Bond Work Index (BWI). HPGR units are more efficient than SAG mills for this specific ore type because they apply “inter-particle comminution,” which uses the pressure between the rocks themselves to cause breakage. This not only consumes less electricity—an important factor in reducing the mine’s carbon footprint—but also produces a “micro-cracked” product that enhances the kinetics of the subsequent cyanide leaching process. By creating these micro-fractures, the cyanide solution can penetrate the particles more effectively, potentially leading to higher gold recoveries compared to traditionally ground ore.
Environmental stewardship and sustainability were integrated into the project’s design from the feasibility stage. The mine’s Tailings Management Facility (TMF) is designed with a focus on long-term stability and water management. Greenstone utilizes a sophisticated water treatment plant to ensure that all discharge meets or exceeds provincial and federal environmental standards. Furthermore, the relocation of a 4.5-kilometer section of Highway 11 was conducted with extensive community consultation and environmental oversight, ensuring that the local infrastructure remained robust while allowing access to the ore body beneath the former roadbed. The project also emphasizes biodiversity, with progressive reclamation plans in place to restore the landscape as mining phases are completed.
The social license to operate has been a cornerstone of the Greenstone development. The mine operates under several Impact Benefit Agreements (IBAs) with local Indigenous communities, including the Animbiigoo Zaagi’igan Anishinaabek, Aroland First Nation, Ginoogaming First Nation, Long Lake #58 First Nation, and the Métis Nation of Ontario. These agreements ensure that the benefits of the mine—ranging from employment and training to business opportunities—are shared equitably. Looking forward, the Greenstone Mine is expected to be a pillar of the Ontario mining industry for decades. With a large mineral resource base and the potential for underground expansion in the future, the processing facility has been designed with flexibility in mind. The current 27,000 tpd throughput is a baseline that the team aims to optimize, leveraging the modular nature of the crushing and grinding circuits to maximize gold output and maintain low all-in sustaining costs (AISC). The successful ramp-up of this facility serves as a blueprint for other large-scale, low-grade gold deposits globally, demonstrating that technological innovation and social responsibility can drive economic success in the modern mining era.
Source: Greenstone
Source: NI 43-101 Technical Report
This article provides an overview of mineral processing developments based on publicly available technical reports and industry analysis.
