Overview
The McIlvenna Bay Project features a conventional copper-zinc processing plant designed to treat 4,900 tonnes per day (1.789 million tonnes annually) of blended ore from the CS and MS mineralization zones. The plant incorporates crushing, grinding, sequential copper-zinc flotation with concentrate regrind, and comprehensive dewatering circuits to produce saleable copper and zinc concentrates while managing tailings through pyrite flotation and paste backfill systems.
Key Process Stages
- Primary Crushing: ROM ore crushed to 100% passing 245 mm (80% passing 125 mm) using FJ 1000 jaw crusher
- Grinding Circuit: SAG mill (7.32m × 3.38m EGL, 3,500 kW) with pebble crusher in closed circuit with ball mill (5.03m × 7.85m EGL, 3,500 kW) producing P80 of 75 µm
- Copper Flotation: Four 50 m³ rougher cells followed by regrind (M1000 IsaMill to P80 25 µm) and three-stage cleaning
- Zinc Flotation: Four 50 m³ rougher cells with regrind (dual M1000 IsaMills to P80 20 µm) and three-stage cleaning
- Pyrite Flotation: Jameson cell followed by three 50 m³ conventional cells for tailings desulphurization
- Concentrate Dewatering: High-rate thickeners (6m for copper, 7m for zinc) producing 55% solids underflow filtered to 9% moisture cake
- Tailings Management: Thickened to 55% solids, filtered to 15% moisture for dry stacking; pyrite concentrate used for paste backfill
Critical Data
| Parameter | Value |
|---|---|
| Nominal Throughput | 4,900 tpd (1.789 Mtpa) |
| Crushing Availability | 60% |
| Grinding Availability | 92% |
| Bond Work Index (Blended) | 14.7 kWh/t (Rod Mill), 16.5 kWh/t (Ball Mill) |
| Plant Feed Grades | 1.27% Cu, 3.64% Zn, 0.56 g/t Au, 18.45 g/t Ag |
| Energy Consumption | 18.4 MW average demand |
| Water Requirement | 42 m³/h raw water |
| Grinding Media Consumption | 0.53 kg/t (SAG), 0.66 kg/t (Ball Mill) |
| Major Reagent Consumption | 93 g/t MIBC, 2,229 g/t Quicklime, 350 g/t Na₂S₂O₅ |
Special Features
The plant incorporates several advanced features including horizontal IsaMills for concentrate regrinding, automated reagent dosing systems, comprehensive water recycling (with 60% solids tailings thickener underflow), and integrated paste backfill production from pyrite concentrate. The metallurgical accounting system includes online stream analyzers (OSA) for real-time process control.
Technical report and processing history
The following archived source profiles have been consolidated here to preserve the project’s processing history and study context.
2025 Technical Report — McIlvenna Bay Project
2025 Technical Report — McIlvenna Bay Project
| Company | Foran Mining |
| Mine | McIlvenna Bay Project |
| Date | 2025 |
| Region | Saskatchewan, Canada |
| Commodities | Copper, Zinc, Gold, Silver |
| Mine Type | Underground |
| Throughput | 4,900 tpd |
| Mine Life | 18 years |
| Annual Production | 1,788,500 dmtpa |
| Status | Under Construction |
Executive Summary
The McIlvenna Bay Project is an underground base and precious metals mine currently under construction in east-central Saskatchewan, Canada. The project is designed to treat copper-zinc sulphide ore with a nominal daily throughput of 4,900 tonnes, targeting an annual production of approximately 1.79 million tonnes over an 18-year mine life. The operation will produce saleable copper and zinc concentrates, with recoverable gold and silver credits, utilizing a conventional metallurgical flowsheet based on extensive test work and industry standards.
The processing plant features a comminution circuit comprising a primary jaw crusher, SAG mill, and ball mill in a closed circuit with cyclone classification. This is followed by sequential copper and zinc flotation circuits, utilizing tank cells for rougher and cleaner duties and horizontal IsaMills for concentrate regrinding. Final concentrates are dewatered using thickeners and horizontal pressure filters to produce filter cakes suitable for transport to toll smelters.
Tailings management involves a desulphurization circuit to produce pyrite concentrate for underground paste backfill, while non-sulphide tailings are filtered and dry-stacked in a Filtered Tailings Storage Facility (FTSF). The project infrastructure includes a compact site layout with a 324-person camp, on-site power generation transitioning to a provincial transmission line, and a comprehensive water management system to ensure environmental compliance and operational efficiency.
Reports
- entities/McIlvenna_Bay_Mine
- entities/Foran_Mining
Concepts
- concepts/Jaw_Crushing
- concepts/SAG_Milling
- concepts/Ball_Milling
- concepts/Flotation
- concepts/Pressure_Filtration
- concepts/Paste_Backfill
Website: https://www.eldoradogold.com/
Report Date: 2025
Region: Saskatchewan, Canada
Project Status: Under Construction
Commodity: Copper, Zinc, Gold, Silver
Throughput: 4,900 tpd
Mine Life: 18 years
Mine Type: Underground
Ore type: Sulphide (Copper-Zinc)
McIlvenna Bay Project — 2025 Technical Report
McIlvenna Bay Project — 2025 Technical Report
| Company | Foran Mining |
| Date | 2025 |
| Region | Saskatchewan, Canada |
| Commodities | Copper, Zinc, Gold, Silver |
| Mine Type | Underground |
| Throughput | 4,900 tpd |
| Mine Life | 18 years |
| Status | Under Construction |
Executive Summary
The McIlvenna Bay Project is an underground base and precious metals mine located in east-central Saskatchewan, approximately 375 km northeast of Saskatoon. Currently under construction, the project is designed to treat copper-zinc sulphide ore with a nominal annual throughput of 1.789 million tonnes per annum (4,900 tpd). The mine is expected to operate for 18 years, producing copper and zinc concentrates along with payable gold and silver credits. The site benefits from existing infrastructure developed during the ADEX program, including access roads and power connections, with plans to transition to a grid-connected transmission line in Phase 2.
The process plant design utilizes a conventional metallurgical flowsheet featuring a comminution circuit followed by sequential copper and zinc flotation. Ore is crushed via a jaw crusher and ground in a SAG and ball mill circuit to a P80 of 75 µm. Concentrates are reground using horizontal IsaMills to fine particle sizes before flotation. The plant includes a pyrite flotation circuit for desulphurization, with pyrite concentrate used for underground paste backfill and non-sulphide tailings stored in a Filtered Tailings Storage Facility (FTSF).
Infrastructure development includes a compact site layout with a 324-person camp, administration offices, and a paste plant integrated with the process building. Power supply will initially rely on onsite LNG generation supplemented by the existing grid, transitioning to a 110/138 kV transmission line from SaskPower. Environmental management focuses on water conservation, contact water treatment, and progressive reclamation of the tailings facility.
Reports
- reports/2025_Foran_McIlvenna_Bay
Website: https://www.eldoradogold.com/
Report Date: 2025
Region: Saskatchewan, Canada
Project Status: Under Construction
Commodity: Copper, Zinc, Gold, Silver
Throughput: 4,900 tpd
Mine Life: 18 years
Mine Type: Underground
Ore type:
McIlvenna Bay Project — 2014 PEA Technical Report
McIlvenna Bay Project — 2014 PEA Technical Report
| Company | Not Specified |
| Date | December 22, 2014 |
| Commodities | Copper, Zinc |
| Throughput | 5,000 tpd |
| Status | PEA (Pre-Feasibility Study) |
Executive Summary
The McIlvenna Bay Project Pre-Feasibility Study outlines a metallurgical processing plant designed to treat copper and zinc bearing material from three distinct mineralization zones (CSZ, L2MS, UWMS). The plant is designed for a throughput of 5,000 tonnes per day (1,825,000 tonnes per annum) and operates on a continuous basis with two 12-hour shifts per day. The flowsheet is engineered to produce copper concentrate, zinc concentrate, or a bulk concentrate depending on the feed mineralization type.
Processing involves conventional crushing followed by a semi-autogenous mill with a pebble crushing circuit and a ball mill grinding circuit. A unique talc pre-flotation step is included to remove detrimental talc prior to the main copper, zinc, and bulk flotation circuits. The flotation process utilizes rougher and scavenger cells for zinc, while copper and bulk circuits use rougher cells only. All ore types require regrinding prior to cleaning, followed by three stages of cleaning to achieve final concentrate grades.
Concentrates are thickened and filtered using dedicated thickeners and filter presses for each product type. Tailings from the talc pre-float and zinc flotation circuits are directed to a common paste backfill system, with thickener underflow sent to the tailings management facility. Process water is recycled from tailings thickening and the management facility, supplemented by fresh water from a lake for gland service and reagent preparation.
Reports
Website: https://www.eldoradogold.com/
Report Date: December 22, 2014
Region:
Project Status: PEA (Pre-Feasibility Study)
Commodity: Copper, Zinc
Throughput: 5,000 tpd
Mine Life:
Mine Type:
Ore type:
