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.
