Source: Seabridge Gold Inc (2026)
Website: https://www.newsfilecorp.com/release/301656/Valor-Gold-Announces-Exploration-Plans-for-the-Courageous-Lake-Project
Critical Data
| Parameter | Value | Unit | Notes |
|---|---|---|---|
| Throughput | 7,500 | t/d | Design throughput; 2.74 Mt/a |
| Mill Power | 6.5 | MW | Primary ball mill installed power |
| Target Grind Size | 106 | µm (P80) | Grinding circuit product size |
| Head Grade | 5.65 | g/t | Gold head grade, design |
| Recovery % | 88 | % | Overall Au recovery to concentrate |
| Processing Capacity | 7,500 | t/d | Same as throughput; design capacity |
| Energy Consumption | 16.5 | kWh/t | Bond ball mill work index (BWi), design |
| Water Consumption | N/A | m³/t | Not provided in source |
| Operating Hours | 7,884 | hours/year | 90% mill availability |
Overview
The Courageous Lake Project, owned by Valor Gold Corp and located in Canada, employs a sophisticated, multi-stage gold recovery process designed to handle variable mineralogy and refractory ore. The flowsheet was selected based on extensive metallurgical testwork and economic modelling, combining standard technologies with a complex pressure oxidation (POX) circuit to achieve high gold and silver extraction. The process begins with three-stage crushing followed by ball mill grinding to a P80 of 106 µm. Rougher and cleaner flotation upgrade the gold-bearing sulphides, producing a concentrate that undergoes acidulation and POX at 200°C to liberate encapsulated gold. The oxidized slurry is washed in a three-stage CCD circuit and then leached with cyanide for 12 hours. Pregnant solution is processed via Merrill-Crowe precipitation, where zinc dust cements gold and silver, which are smelted into doré bars. Tailings are detoxified using the SO₂/air process before disposal. With a design throughput of 7,500 t/d and a gold head grade of 5.65 g/t, the recovery methods at Courageous Lake are optimized for both refractory and free-milling ore fractions, making it a significant gold project in Canada. The plant achieves 88% gold recovery to concentrate and 97% leach circuit extraction, underscoring the effectiveness of the integrated flowsheet. This comprehensive gold recovery process reflects the project’s commitment to technical robustness and environmental responsibility.
Key Process Stages
- Stage 1: Crushing and Grinding – Run-of-mine ore is reduced through a primary jaw crusher (110 kW), secondary cone crusher (335 kW), and tertiary cone crusher (480 kW) to a P80 of 9 mm. Crushed material is stockpiled and fed to a 6.5 MW ball mill operating in closed circuit with cyclones, producing a grinding circuit product P80 of 106 µm. Process water is added to maintain mill discharge at 70% solids.
- Stage 2: Rougher and Cleaner Flotation – Cyclone overflow at 35% solids reports to five rougher flotation cells (58 m³ each) using PAX, CuSO₄, and MIBC. Rougher concentrate (max 11% mass pull) is upgraded in four cleaner cells (12 m³ each) to a maximum of 4.2% mass pull, achieving 88% Au and 85% Ag recovery to concentrate. Cleaner concentrate is reground in a 100 kW ball mill to a P80 of 43 µm.
- Stage 3: Concentrate Acidulation and Pressure Oxidation – Reground concentrate at 50% solids is acidulated with sulfuric acid at 50°C for 1 hour to decompose carbonates, then fed to a horizontal autoclave operating at 200°C and 2,150 kPa with 90 minutes residence time. Oxygen sparging maintains 690 kPa partial pressure. Oxidized slurry is flashed to atmospheric pressure and washed in a three-stage CCD circuit.
- Stage 4: Cyanide Leaching and CCD – Neutralized solids (pH 10.5–11) are leached in three agitated tanks with cyanide and oxygen for 12 hours. Leach extraction is 97% Au and 69% Ag. A six-stage CCD circuit washes the leach residue with a 5:1 wash ratio, achieving >99% washing efficiency. Pregnant solution is clarified before Merrill-Crowe.
- Stage 5: Merrill-Crowe Precipitation and Refining – Clarified pregnant solution is de-aerated in a tower and mixed with zinc dust, lead nitrate, and cyanide to precipitate gold and silver. Precipitation efficiency exceeds 99%. The precipitate is filtered, dried, and smelted in an induction furnace to produce gold-silver doré bars. Barren solution is recycled to the CCD circuit.
Additional Interesting Data and Summary
The Courageous Lake Project recovery methods incorporate extensive technical data to ensure robust performance across variable ore types. Key design parameters include a Bond crusher work index of 24 kWh/t, a Bond rod mill work index of 18.1 kWh/t, and a Bond abrasion index of 0.19. The regrind mill specific energy is 9.2 kWh/t, and the oxidation circuit operates at 200°C with a design pressure of 2,580 kPag. The POX circuit has a residence time of 90 minutes, followed by a three-stage CCD with a 3:1 wash ratio. Cyanide leaching residence time is 12 hours, and the Merrill-Crowe circuit achieves >99% precipitation efficiency using zinc dust and lead nitrate. The cyanide destruction system, employing the SO₂/air process, reduces WAD cyanide to <25 mg/L in tailings before disposal to the Leach Residue Tailings Facility (LRTF). Reagent handling and storage are designed for 12-month supply via winter road deliveries, with lime, copper sulphate, PAX, MIBC, flocculant, and sodium cyanide stored on site. Annual reagent consumption is summarized in the report but not detailed here. Environmental considerations are integrated throughout: acidic solutions from POX are neutralized with lime and flotation tailings to pH 8.5–10.5, and the plant includes dust collection and HCN gas detection systems. Economically, the project is based on a 12.6-year mine life at 2.74 Mt/a throughput, with processing costs optimized through trade-off studies. Sustainability initiatives include high water recycling via CCD circuits and detoxification of tailings. Future outlook, as noted in Section 25.3.2.3, identifies opportunities for further optimization based on 2023 testwork, potentially improving recovery and reducing costs. The facility’s design emphasizes operational reliability with 90% availability for grinding and oxidation circuits, and a plant layout that minimizes footprint while enabling safe, efficient maintenance. This gold recovery process sets a benchmark for refractory ore treatment in northern Canada, balancing technical complexity with environmental stewardship and economic viability.
Key Processes: Flotation, Cyanidation, Gravity Separation, Ball Mill, Crushing
Target Commodities: Gold, Silver, Copper, Zinc, Lead
Technical report and processing history
The following archived source profiles have been consolidated here to preserve the project’s processing history and study context.
Courageous Lake Gold Recovery: POX & Merrill-Crowe Process
Courageous Lake Gold Recovery: POX & Merrill-Crowe Process
Source: Unnamed_Company_16 (2026)
Website: https://www.newsfilecorp.com/release/301656/Valor-Gold-Announces-Exploration-Plans-for-the-Courageous-Lake-Project
Critical Data
| Parameter | Value | Unit | Notes |
|---|---|---|---|
| Throughput | 7,500 | tpd | Design throughput per day |
| Mill Power | 6.5 | MW | Primary ball mill installed power |
| Target Grind Size | 106 | μm (P80) | Primary grinding circuit product size |
| Head Grade | 5.65 | g/t | Gold feed grade design |
| Recovery % | 88 | % | Overall gold recovery to flotation concentrate |
| Processing Capacity | 2.74 | Mt/a | Annual plant throughput |
| Energy Consumption | 9.2 | kWh/t | Regrind mill specific energy |
| Water Consumption | Not provided | m³/t | Water usage data not available in source |
| Operating Hours | 21.6 | hours/day | Derived from 90% availability (7,884 h/year) |
Overview
Valor Gold Corp’s Courageous Lake Project employs a comprehensive gold recovery flowsheet designed to process refractory sulfide ore at a design throughput of 7,500 tonnes per day. The project, supported by a pre-feasibility study effective January 2024 and amended in March 2026, is situated in Canada and leverages a three-stage crushing circuit, primary ball mill grinding, sequential rougher and cleaner flotation, pressure oxidation (POX), cyanide leaching, and Merrill-Crowe precipitation to produce gold-silver doré bars. The flowsheet was selected based on extensive metallurgical testwork from programs conducted by SGS (2003, 2011), G&T (2007), and ALS (2023), addressing variable mineralogy, feed grades, and rock hardness. The process begins with run-of-mine material crushed to a P80 of 9 mm, followed by grinding to 106 µm with a 6.5 MW ball mill. Flotation concentrates gold-bearing sulfides, achieving 88% recovery to concentrate, which is then reground to 43 µm and acidulated before entering the POX autoclave (200°C, 2,150 kPa, 90-minute residence). Oxidized slurry is washed via three-stage counter-current decantation (CCD), neutralized, and leached with cyanide for 12 hours, achieving 97% gold extraction. The pregnant solution undergoes Merrill-Crowe zinc cementation (>99% efficiency), and the precipitate is smelted into doré bars. The facility includes robust reagent handling with on-site storage for 12 months, a cyanide destruction circuit using the SO2/air process to reduce WAD cyanide below 25 mg/L, and comprehensive environmental controls. This integrated gold recovery methods approach represents a technologically advanced solution for refractory gold deposits, with optimization opportunities identified for future implementation.
Key Process Stages
- Stage 1: Crushing and Stockpiling – Run-of-mine material feeds a primary jaw crusher (110 kW) via a vibrating grizzly, with oversize reduced to a P80 of 94 mm. Secondary and tertiary cone crushers (335 kW and 480 kW respectively) further reduce the material to a final product P80 of 9 mm. A fine ore stockpile with 12-hour live capacity ensures consistent feed to the grinding circuit. Belt magnets and metal detectors remove tramp metal throughout the crushing stages.
- Stage 2: Primary Grinding and Classification – Reclaimed material is fed to a 6.5 MW ball mill operating in closed circuit with a cyclone cluster. Process water maintains mill discharge at 70% solids, and the circuit is designed for 347 t/h throughput at 90% availability. Cyclone overflow at 35% w/w solids reports to flotation with a target P80 of 106 µm. Copper sulphate and promoter are added to the cyclone feed pumpbox to activate gold-bearing sulfides.
- Stage 3: Flotation (Rougher and Cleaner with Regrind) – Rougher flotation uses five 58 m³ cells with PAX collector, copper sulphate activator, and MIBC frother to produce a concentrate at 25% w/w solids. Rougher tailings combine with cleaner tailings for thickening. Cleaner flotation (four 12 m³ cells) upgrades the rougher concentrate, which is then reground in a 100 kW ball mill in closed circuit with cyclones to achieve a product P80 of 43 µm. Cleaner mass pull is limited to 4.2% of overall circuit feed.
- Stage 4: Pressure Oxidation and CCD – Reground concentrate slurry (50% w/w solids) is acidulated with sulfuric acid at 50°C in two agitated tanks (1-hour residence) to remove carbonates, reducing CO₂ generation in the autoclave. The acidulated slurry is fed to a horizontal autoclave with four compartments, operating at 200°C and 2,150 kPa (oxygen partial pressure 690 kPa) for 90 minutes. Oxidation autogenously maintains temperature. Oxidized slurry is flashed to atmospheric pressure and washed in a three-stage CCD circuit (3:1 wash ratio) to remove acid. A portion of the acidic overflow is recycled to pre-acidulation; the remainder is neutralized with lime and flotation tailings.
- Stage 5: Cyanide Leaching and Merrill-Crowe – Neutralized oxidized slurry (pH 10.5–11, 40% solids) undergoes cyanide leaching in three agitated tanks with oxygen sparging (20 ppm DO) for 12 hours, targeting 97% Au and 69% Ag extraction. The leached slurry is washed in a six-stage CCD circuit (5:1 wash ratio, >99% washing efficiency). Pregnant solution is clarified and deoxygenated, then mixed with zinc dust, lead nitrate, and cyanide in the Merrill-Crowe circuit (>99% precipitation efficiency). Precipitate is filtered and smelted in an induction furnace to produce gold-silver doré bars. Barren solution is recycled to CCD washing. Cyanide destruction using the SO₂/air process (1.5 hours residence) reduces WAD cyanide to <25 mg/L before tailings disposal.
Additional Interesting Data and Summary
The Courageous Lake Project’s gold recovery methods are underpinned by extensive design criteria summarized in Table 17-1. Key metallurgical parameters include head grades for gold (5.65 g/t), silver (0.8 g/t), sulfur (0.48%), arsenic (0.3%), and iron (2.3%). The flotation circuit achieves 85% silver recovery to concentrate, while the leach circuit extracts 97% gold and 69% silver. The POX autoclave operates at 90-minute residence time, 200°C, and 2,150 kPa, with oxygen partial pressure of 690 kPa. The three-stage CCD after POX uses a 3:1 wash ratio, and the six-stage CCD after leaching uses a 5:1 wash ratio to achieve >99% washing efficiency. The Merrill-Crowe circuit demonstrates >99% precipitation efficiency for both gold and silver. Cyanide destruction via the SO₂/air process treats leach residue in two parallel tanks (90 minutes residence) to reduce WAD cyanide below 25 mg/L. Reagent handling includes 12-month on-site storage for all consumables delivered via winter road. Key reagents include quicklime (slaked on site), copper sulphate (15% solution), PAX collector, Aero 208 promoter, MIBC frother, flocculant, and sodium cyanide. Environmental controls are integrated throughout: acidic solutions from POX are neutralized with lime and flotation tailings to pH 8.5 (solution) and pH 10.5–11 (solids) prior to leaching or disposal. The plant layout ensures dust collection, HCN gas detection, and secure gold room facilities. Economically, the pre-feasibility study and preliminary economic assessment (PEA) formed the basis for flowsheet selection, minimizing capital and operating costs without compromising functionality. The 2023 ALS testwork confirmed design parameters and identified optimization opportunities (see Section 25.3.2.3) for future implementation, such as potential improvements in reagent consumption or circuit configuration. The facility’s 12.6-year mine life at 2.74 Mt/a throughput underscores the project’s long-term significance in processing refractory gold ore. Forward-looking statements include continued refinement of the flowsheet to enhance gold recovery methods for this complex sulfide deposit.
Key Processes: Flotation, Cyanidation, Gravity Separation, Ball Mill, Crushing
Target Commodities: Gold, Silver, Copper, Zinc, Lead
Courageous Lake Project — 2024 Pre-feasibility Study
This technical report presents the proposed mineral processing flowsheet for the Courageous Lake Project, based on 2024 pre-feasibility study metallurgical testwork and historical data.
Report context
The Courageous Lake Pre-feasibility Study and Preliminary Economic Assessment NI 43-101 Technical Report, effective January 5, 2024, was prepared for Seabridge Gold Inc. by Ausenco Engineering Canada ULC and Ausenco Sustainability ULC, with contributions from ERM Consultants Canada Ltd., Moose Mountain Technical Services Ltd., WN Brazier Associates Inc., Tetra Tech Canada Inc., and SRK Consulting (Canada) Inc. This report includes summary information for the overall project, with detailed processing information in sections 1.9, 1.13, 1.14.2, 1.14.3.2, 13, 17, 18.1-2, 18.3.4-6, 18.4.3-4, 18.5, 18.6.2-4, 19, 21.1, 21.2.1-2, 21.2.4-5, 21.2.6.1-2, 21.2.6.4, 21.2.7-10, 21.3.1-2, 21.3.4-5, 22, 24.1.1, 24.1.4, 24.1.5.1, 24.1.5.3.2-3, 24.1.6, 24.1.8-9, 25.1.1, 25.1.5, 25.1.8, 25.1.9.1-2, 25.1.9.3.2, 25.1.11-13, 25.2.1, 25.2.3, 25.2.4.1, 25.2.5, and 25.3.1.1. This article summarizes the proposed recovery methods as described in the original report.
Processing route
Metallurgical Testwork Programs
Metallurgical testwork for the Courageous Lake Project was conducted in multiple phases. SGS-Lakefield completed a program in 2010/2011, and ALS completed a program in 2023. Earlier testwork included SGS programs from 2003/2004, a G&T program from 2007, and an SGS program for the Walsh Lake Deposit in 2013. Sample selection for these programs is described in the original report section 13.2.
Head Assays
Head assays were completed for the SGS-Lakefield program (2010/2011) and the ALS program (2023), as detailed in section 13.3 of the original report.
Mineralogy
Mineralogical studies were completed during the SGS program (2003/2004), the G&T program (2007), and the ALS program (2023). These studies are described in original report section 13.4.
Comminution Testing
Comminution testing was completed as part of the metallurgical testwork programs, as referenced in section 13.5 of the original report.
Pre-concentration (Ore Sorting)
Ore sorting testwork was conducted as part of the metallurgical evaluation, as described in section 13.6 of the original report.
Gravity Concentration
Gravity concentration testwork was conducted and is described in section 13.7 of the original report.
Rougher Flotation
Rougher flotation testwork was completed during the SGS (2011) program and the ALS (2023) program. Results from these programs are detailed in sections 13.8.1 and 13.8.2 of the original report.
Cleaner Flotation
Cleaner flotation testwork was completed during the SGS (2003), SGS (2011), and ALS (2023) programs. Results from these programs are detailed in sections 13.9.1, 13.9.2, and 13.9.3 of the original report.
Direct Cyanidation
Direct cyanidation testwork was performed, including cyanide leach of flotation tail, as described in sections 13.10 and 13.10.1 of the original report.
Pressure Oxidation
Pressure oxidation (POX) testwork was completed and is described in section 13.11 of the original report.
Cyanide Destruction Testwork
Cyanide destruction testwork was performed and is described in section 13.12 of the original report.
Solid Liquid Separation
Solid liquid separation testwork was completed and is described in section 13.13 of the original report.
Recovery Estimate
Recovery modelling was conducted and is described in sections 13.14 and 13.14.1 of the original report.
Deleterious Elements
Deleterious elements were evaluated as part of the metallurgical testwork, as described in section 13.15 of the original report.
Walsh Lake Deposit Metallurgy
Metallurgical testwork for the Walsh Lake Deposit was completed by SGS in 2013. This included head assay analysis (section 13.16.1), direct cyanidation testwork (section 13.16.2), and flotation testwork (section 13.16.3).
Process Flow Sheet
The proposed process flow sheet for the Courageous Lake Project is described in section 17.2 of the original report. The flowsheet includes crushing and stockpiling, primary grinding and classification, flotation, concentrate acidulation, pressure oxidation (POX), POX counter current decantation (CCD), POX acidic solution neutralization, POX solids neutralization, cyanide leach, counter current decantation (CCD), Merrill-Crowe precipitation circuit, refining circuit, and cyanide destruction and neutralized tailings disposal.
Plant Design
Crushing and Stockpiling
The crushing and stockpiling circuit design is described in section 17.3.1 of the original report.
Primary Grinding and Classification
The primary grinding and classification circuit design is described in section 17.3.2 of the original report.
Flotation
The flotation circuit design is described in section 17.3.3 of the original report.
Concentrate Acidulation
The concentrate acidulation circuit design is described in section 17.3.4 of the original report.
Pressure Oxidation (POX)
The pressure oxidation circuit design is described in section 17.3.5 of the original report.
POX Counter Current Decantation (CCD)
The POX counter current decantation circuit design is described in section 17.3.6 of the original report.
POX Acidic Solution Neutralization
The POX acidic solution neutralization circuit design is described in section 17.3.7 of the original report.
POX Solids Neutralization
The POX solids neutralization circuit design is described in section 17.3.8 of the original report.
Cyanide Leach
The cyanide leach circuit design is described in section 17.3.9 of the original report.
Counter Current Decantation (CCD)
The counter current decantation circuit design is described in section 17.3.10 of the original report.
Merrill-Crowe Precipitation Circuit
The Merrill-Crowe precipitation circuit design is described in section 17.3.11 of the original report.
Refining Circuit
The refining circuit design is described in section 17.3.12 of the original report.
Cyanide Destruction and Neutralized Tailings Disposal
The cyanide destruction and neutralized tailings disposal circuit design is described in section 17.3.13 of the original report.
Reagent Handling and Storage
Reagent handling and storage systems are described in section 17.4 of the original report for lime, activators, collectors, promoter, frother, flocculant, sodium cyanide, sodium metabisulphite, sulfuric acid, zinc powder, lead nitrate, diatomaceous earth, and oxygen.
Plant Services
Plant services are described in section 17.5 of the original report for process water, raw water, potable water, and power.
Key reported parameters
| Parameter | Unit | Value | Basis |
|---|---|---|---|
| Metallurgical testwork programs | , | SGS-Lakefield (2010/2011), ALS (2023) | Testwork |
| Additional testwork | , | SGS (2003/2004), G&T (2007), SGS (2013 Walsh Lake) | Testwork |
| Comminution testing | , | Completed | Testwork |
| Pre-concentration (ore sorting) testwork | , | Completed | Testwork |
| Gravity concentration testwork | , | Completed | Testwork |
| Rougher flotation testwork | , | SGS (2011), ALS (2023) | Testwork |
| Cleaner flotation testwork | , | SGS (2003), SGS (2011), ALS (2023) | Testwork |
| Direct cyanidation testwork | , | Completed | Testwork |
| Pressure oxidation testwork | , | Completed | Testwork |
| Cyanide destruction testwork | , | Completed | Testwork |
| Solid liquid separation testwork | , | Completed | Testwork |
| Recovery modelling | , | Completed | Testwork |
| Deleterious elements evaluation | , | Completed | Testwork |
| Proposed process flowsheet | , | Crushing, grinding, flotation, acidulation, POX, CCD, neutralization, cyanide leach, Merrill-Crowe, refining, cyanide destruction | Proposed design |
| Walsh Lake deposit testwork | , | SGS (2013): head assay, direct cyanidation, flotation | Testwork |
Project website: https://www.rcaanc-cirnac.gc.ca/eng/1292948193972/1543262085000
Technical qualifications
This article is a summary of a NI 43-101 Technical Report with an effective date of January 5, 2024. The original report was prepared for Seabridge Gold Inc. by multiple consulting firms, and the qualified persons responsible for the processing sections did not all conduct site visits. Kevin Murray, P. Eng., responsible for sections including 13 (Mineral Processing and Metallurgical Testing) and 17 (Recovery Methods), did not visit the Courageous Lake Project. The report notes that certain sections were prepared by qualified persons with relevant experience, and the information, conclusions, and estimates contained in the report are based on information available at the time of preparation, data supplied by outside sources, and the assumptions, conditions, and qualifications set forth in the report. Specific processing parameters such as throughput rates, metallurgical recoveries, reagent consumptions, and capital and operating costs are not included in this summary article as they are not explicitly provided in the processing sections of the original report markdown provided.
Source: Courageous Lake Pre-feasibility Study and Preliminary Economic Assessment NI 43-101 Technical Report, effective date January 5, 2024, sections 1.9, 1.13, 13, 17, 18.1-2, 18.3.4-6, 18.4.3-4, 18.5, 18.6.2-4, 19, 21, 22, 24, 25.
