Overview
The Rainy River Mine processing plant is a conventional gold and silver recovery facility that began operations in September 2017. The plant achieved commercial production in October 2017 and processed 8.99 million tonnes in 2024, averaging 24,563 tonnes per day (tpd) with metallurgical recoveries of 91.8% gold and 61.1% silver. The circuit features crushing, grinding, gravity concentration, leaching, carbon adsorption, and electrowinning.
Key Process Stages
- Crushing: Primary crushing via a 1,400 × 2,100 mm gyratory crusher (600 kW) with a P80 product size of 120 mm. Ore is stockpiled in an 85,690-tonne coarse ore stockpile.
- Grinding: SAG mill (11.0 m × 6.1 m, 15,000 kW) with pebble crushing (Raptor L500 cone crusher, 447 kW). Ball mill (7.9 m × 12.3 m, 15,000 kW) targets a P80 of 80 µm.
- Gravity Concentration: Two 48-inch Knelson concentrators (600 tph combined) recover free gold, with concentrate processed in an Acacia intensive cyanide leach circuit.
- Leaching & CIP: Eight 18 m-diameter leach tanks (24-hour retention) and seven 7 m-diameter CIP tanks (1.5-hour retention) for gold adsorption.
- Carbon Stripping: Zadra process (high-pressure, high-temperature) with two 10-tonne stripping vessels. Reactivation in a 750°C rotary kiln.
- Electrowinning: Three parallel trains (two cells each) recover gold/silver sludge, which is smelted into doré bars.
- Tailings: Cyanide destruction (SO₂/lime) before pumping to the Tailings Management Area (TMA) via 550 kW centrifugal pumps.
Critical Data
| Parameter | Value |
|---|---|
| Throughput (2024) | 8.99 Mt (24,563 tpd) |
| Gold Recovery | 91.8% |
| Silver Recovery | 61.1% |
| SAG Mill Energy | 8.8 kWh/t |
| Ball Mill Energy | 13 kWh/t |
| Total Site Energy | 34.5 kWh/t |
| Reagent Consumption (kg/t) | Sodium Cyanide: 0.21, Lime: 0.72, Activated Carbon: 0.027 |
| Water Storage (TMA) | 11.6 million m³ |
Based on filing data from 2024-2025.
Technical report and processing history
The following archived source profiles have been consolidated here to preserve the project’s processing history and study context.
Rainy River Mine — 2022 Technical Report
Rainy River Mine — 2022 Technical Report
| Company | New Gold |
| Date | 2022 |
| Region | Ontario, Canada |
| Commodities | Gold, Silver |
| Mine Type | Open Pit and Underground |
| Throughput | 27,000 tpd (LOM) |
| Mine Life | LOM (Years not specified) |
| Status | Operating |
Executive Summary
The Rainy River processing plant was originally designed to process 7.7 Mtpa (21,000 tpd) from open pit and underground mines. Commercial production commenced in mid-October 2017, and the plant has consistently increased throughput, reaching 25,341 tpd in 2021. The program aims to achieve approximately 26,550 tpd in 2022, with a Life of Mine (LOM) throughput averaging approximately 27,000 tpd.
The processing flowsheet includes primary gyratory crushing, SAG and ball milling, gravity concentration using Knelson concentrators, and gold recovery via intensive cyanide leaching and Carbon-in-Pulp (CIP). Gravity concentrate is treated in an Acacia reactor, while the main slurry undergoes cyanide leaching followed by CIP. Gold and silver are recovered via electrowinning and smelted into doré bars. Cyanide destruction is performed using the sulphur dioxide-air process.
Recent studies by Halyard investigated reducing plant throughput to 4-5 ktpd to accommodate underground-only mining after open pit depletion. Option 2b, involving a turn-down of the SAG and ball mill for warm weather operation, was recommended as the preferred option due to lower capital costs and operational advantages over year-round stop/start operations.
Processing Profile
- Crushing: Gyratory Crusher (1,400 mm x 2,100 mm)
- Milling: 11.0 m SAG Mill, 7.9 m Ball Mill
- Gravity: Knelson Centrifugal Concentrators
- Leaching: Cyanide Leaching, CIP Circuit, Acacia Reactor
- Carbon: Zadra Process, Regeneration Kiln
- Cyanide Destruction: SO2/Air Process
Reports
Website: https://rainyriver.newgold.com/
Report Date: 2022
Region: Ontario, Canada
Project Status: Operating
Commodity: Gold, Silver
Throughput: 27,000 tpd (LOM)
Mine Life: LOM (Years not specified)
Mine Type: Open Pit and Underground
Ore type:
NI 43-101 Technical Report for the Rainy River Mine
NI 43-101 Technical Report for the Rainy River Mine
| Company | New Gold Inc. |
| Date | 2019 |
| Region | Ontario, Canada |
| Commodities | Gold, Silver |
Executive Summary
The Rainy River process plant commenced ore processing in September 2017 and commercial production in mid-October 2017. The plant achieved daily throughputs in the 22,000 tpd – 24,000 tpd range in 2019, with a programmed target of 25,300 tpd in 2020 and a Life of Mine (LOM) average of approximately 25,800 tpd. The mine operates primarily as an open pit with planned underground mining from 2022 through Q1-2028, integrating low-grade stockpiles and underground ore for economic processing.
The processing flowsheet includes a gyratory crusher, SAG mill, and ball mill for comminution, followed by gravity concentration using Knelson centrifuges. The gravity concentrate undergoes intensive cyanide leaching in an Acacia reactor, while the main slurry proceeds to a Carbon-in-Pulp (CIP) circuit. Gold and silver are recovered via electrowinning and cast into doré bars. Cyanide destruction is performed using the sulphur dioxide-air process to meet environmental standards.
Future plant debottlenecking projects include improvements to the pre-leach thickener, dust suppression on the crushed ore stockpile, and a booster pump station for tailings pumping to sustain 27,000 tpd nominal throughput. Comminution simulations by OMC suggest potential throughput increases through SAG mill speed optimization and grate configuration changes.
Website: https://rainyriver.newgold.com/
Report Date: 2019
Region: Ontario, Canada
Project Status:
Commodity: Gold, Silver
Throughput:
Mine Life:
Mine Type:
Ore type:
Rainy River Mine — 2018 Technical Report
Rainy River Mine — 2018 Technical Report
| Company | New Gold Inc. |
| Date | 2018 |
| Region | Ontario, Canada |
| Commodities | Gold, Silver |
| Mine Type | Open Pit, Underground |
| Throughput | 21,000 tpd (Design), 27,000 tpd (Target 2021) |
| Mine Life | 8.5 years |
| Status | Operating |
Executive Summary
The Rainy River Mine processing facilities were designed to process 21,000 tpd from open pit and underground mines, with a target production of 19,500 tpd from the open pit and 1,500 tpd from the underground mine. The plant was commissioned in September 2017 and has been working through initial operating and maintenance issues. An expansion plan was identified to increase plant throughput to 24,000 tpd in 2019 and 2020, followed by a ramp-up to 27,000 tpd in 2021 for the remainder of the mine life.
The process flowsheet consists of primary gyratory crushing, SAG mill grinding, pebble crushing, secondary ball mill grinding, gravity concentration using centrifugal concentrators, intensive cyanide leaching of the gravity concentrate, and cyanide leaching using eight tanks in series. Gold recovery is achieved using Carbon in Pulp (CIP) with seven tanks in series, followed by carbon stripping using the Zadra process, acid washing, and electrowinning of the carbon eluent and gravity concentrate leach solution. Gold and silver bars are cast in an induction furnace.
Performance statistics indicate that production rates are approaching the targeted 21,000 tpd, however, plant availability has been lower than projected. Key operating parameters include a primary crusher availability of 65% and process plant availability of 92%. The study identified sections of the plant, including the carbon elution and cyanide destruction circuits, that require modification to achieve required performance. A debottlenecking feasibility study was performed to review the elution circuit and prepare recommendations for plant improvement.
Processing Overview
- Crushing: Primary Gyratory Crusher (1,400 mm x 2,100 mm)
- Milling: SAG Mill (11.0 m diameter), Ball Mill (7.9 m diameter)
- Gravity: Knelson Centrifugal Concentrators
- Leaching: Cyanide Leaching (8 tanks), Carbon in Pulp (CIP) (7 tanks)
- Elution: Zadra Process
- Refining: Electrowinning, Induction Furnace
- Cyanide Destruction: SO2-Air Process
Website: https://rainyriver.newgold.com/
Report Date: 2018
Region: Ontario, Canada
Project Status: Operating
Commodity: Gold, Silver
Throughput: 21,000 tpd (Design), 27,000 tpd (Target 2021)
Mine Life: 8.5 years
Mine Type: Open Pit, Underground
Ore type:
Rainy River Project — Feasibility Study Technical Report
Rainy River Project — Feasibility Study Technical Report
| Company | Not Specified in Text |
| Mine | Rainy River Project |
| Date | 2018 |
| Region | Not Specified in Text |
| Commodities | Gold, Silver |
| Mine Type | Open Pit and Underground |
| Throughput | 21,000 tpd |
| Mine Life | 13.6 years |
| Status | Feasibility Study |
Executive Summary
This NI 43-101 Technical Report presents the Feasibility Study for the Rainy River Project, outlining a comprehensive process flowsheet developed based on metallurgical testwork conducted at SGS Lakefield and BBA’s experience. The proposed flowsheet includes crushing, grinding, gravity recovery, cyanide leaching, carbon-in-pulp circuit, electrowinning, and refining. The design and sizing of equipment were based on a total process plant throughput of 21,000 tpd, or 7.7 Mtpa, which includes 1,500 tpd from the underground mine starting in Year 3.
The plant design features a primary gyratory crusher, a single SAG mill, and a single ball mill in a closed-circuit grinding configuration. The ore is processed through a gravity recovery circuit before entering the cyanide leaching circuit, which utilizes eight agitated leach tanks with a 30-hour retention time. The leached slurry is then treated in a carousel-style Carbon-in-Pulp (CIP) circuit consisting of seven tanks to recover gold and silver.
The study details the operational parameters for the entire processing plant, including reagent consumption, energy requirements, and tailings management. The cyanide destruction circuit employs a conventional liquid SO2/air process to ensure safe discharge into the tailings pond. The project demonstrates a robust design for processing blended open pit and underground ore with an average feed grade of 1.48 g/t Au and 3.13 g/t Ag over the first 8.5 years of operation.
Reports
Website: https://rainyriver.newgold.com/
Report Date: 2018
Region: Not Specified in Text
Project Status: Feasibility Study
Commodity: Gold, Silver
Throughput: 21,000 tpd
Mine Life: 13.6 years
Mine Type: Open Pit and Underground
Ore type:
Rainy River Gold Project — 2012 Technical Report
Rainy River Gold Project — 2012 Technical Report
| Company | Rainy River Resources Ltd |
| Date | 2012-04-09 |
| Region | Ontario, Canada |
| Commodities | Gold, Silver |
Executive Summary
The 2012 Technical Report for the Rainy River Gold Project presents a Preliminary Economic Assessment (PEA) developed by BBA. The study evaluates a proposed process flowsheet based on testwork by SGS, comparing a whole rock leach option against a flotation concentrate leach option. The flotation concentrate leach was selected as the more favourable flowsheet due to lower operating costs despite slightly lower overall gold recovery compared to the whole rock option. The plant is designed for a throughput of 32,000 tonnes per day (tpd) with a mine life of 13.4 years, utilizing a combination of open pit and underground mining sources.
The processing circuit includes primary crushing via a gyratory crusher, followed by SAG and ball milling. The ore undergoes rougher and cleaner flotation to produce a concentrate, which is then reground using Tower and Stirred Mills to a fine particle size. The concentrate is subjected to cyanide leaching followed by a Carbon-in-Pulp (CIP) circuit for gold recovery, with final product refined into doré bars via electrowinning and smelting. The study also assessed the integration of a gravity circuit but concluded it offered no significant economic benefit.
The project is located in Ontario, Canada, and targets Gold and Silver commodities. The ore is treated as sulphide, with tailings managed in separate Non-Acid Generating (NAG) and Potentially Acid Generating (PAG) ponds. Reagent consumption includes lime, cyanide, oxygen, and flotation collectors, with specific attention paid to cyanide destruction to meet regulatory standards. The design accounts for a total power demand of approximately 46.3 MW during peak operational years.
Reports
Entities
Website: https://rainyriver.newgold.com/
Report Date: 2012-04-09
Region: Ontario, Canada
Project Status:
Commodity: Gold, Silver
Throughput:
Mine Life:
Mine Type:
Ore type:
Rainy River Gold Project — 2012 Resource Update Technical Report
Rainy River Gold Project — 2012 Resource Update Technical Report
| Company | Rainy River Resources Ltd. |
| Date | 2012-04-09 |
| Region | Ontario, Canada |
| Commodities | Gold, Silver |
Executive Summary
This technical report details the recovery methods for the Rainy River Gold Project, based on a Preliminary Economic Assessment (PEA) conducted by BBA. The selected flowsheet utilizes a flotation concentrate leach option, determined to be more favorable than whole rock leach due to lower operating costs despite slightly lower overall gold recovery. The plant is designed for a throughput of 32,000 tpd, processing material from both open pit and underground sources over a mine life of 13.4 years. Key processing steps include gyratory crushing, SAG and ball milling, flotation, regrinding, cyanide leaching, and carbon-in-pulp recovery.
The study evaluated multiple flowsheets including gravity recovery circuits, concluding that integration of a gravity circuit was not beneficial due to increased operating costs negating recovery gains. The process plant layout allows for future integration if required. The design accounts for three main mineral processing buildings: primary crushing, pebble crushing, and the main process plant. Tailings management involves separate Non-Acid Generating and Potentially Acid Generating ponds with cyanide destruction circuits to meet regulatory standards.
Reports
Website: https://rainyriver.newgold.com/
Report Date: 2012-04-09
Region: Ontario, Canada
Project Status:
Commodity: Gold, Silver
Throughput:
Mine Life:
Mine Type:
Ore type:
PEA of the Rainy River Gold Project — 2012 Technical Report
PEA of the Rainy River Gold Project — 2012 Technical Report
| Company | Agnico Eagle Mines |
| Mine | Rainy River Gold Project |
| Date | 2012 |
| Region | Ontario, Canada |
| Commodities | Gold, Silver |
| Mine Type | Open Pit and Underground |
| Throughput | 20,000 tpd |
| Mine Life | 16 years |
| Status | Development |
Executive Summary
This NI 43-101 Technical Report presents the Preliminary Economic Assessment (PEA) for the Rainy River Gold Project. The report details the proposed process flowsheet selected after a trade-off study between a whole rock leach (WRL) option and a flotation concentrate leach option. The WRL option was chosen due to higher overall gold recovery (92.0% vs 87.5%), similar capital costs, and significantly higher IRR and NPV compared to the flotation option. The design is based on metallurgical testwork conducted at SGS Lakefield and equipment supplier data.
The process plant is designed for a throughput of 20,000 tonnes per day (tpd), or 7.3 million tonnes per annum (Mtpa), with a mine life of 16 years. The flowsheet includes primary crushing via a gyratory crusher, grinding using a SAG mill and ball mill circuit, gravity recovery, cyanide leaching, carbon-in-pulp (CIP) recovery, and electrowinning. Reagent requirements include lime, sodium cyanide, oxygen, and caustic soda, with specific consumption rates detailed for the plant design.
Processing Profile
- Crushing: Primary Gyratory Crusher
- Milling: 13,000 kW SAG Mill, 13,000 kW Ball Mill
- Leaching: Whole Rock Cyanide Leach (WRL)
- Recovery: Carbon-in-Pulp (CIP), Gravity Concentrators
- Refining: Electrowinning, Induction Furnace
Reports
Website: https://www.juniorminingnetwork.com/junior-miner-news/press-releases/2816-tsx-venture/qgr/175280-q-gold-plans-exploration-program-at-its-mine-centre-project.html
Report Date: 2012
Region: Ontario, Canada
Project Status: Development
Commodity: Gold, Silver
Throughput: 20,000 tpd
Mine Life: 16 years
Mine Type: Open Pit and Underground
Ore type:
