Overview
The Red Lake Operations in Ontario, Canada feature two sophisticated processing complexes (Red Lake and Campbell) designed to recover gold through multiple methods including gravity concentration, cyanidation, flotation, and pressure oxidation. The modernized Red Lake Complex (commissioned 2001) processes 1,250 t/d while the Campbell Complex (originally built 1949) handles 1,800 t/d of both free-milling and refractory gold ores.
Key Process Stages
- Crushing: Two-stage reduction from 30 cm to 1 cm using jaw crusher, cone crusher, and sizing screens
- Gravity Concentration: Knelson concentrators (3 units) recover coarse gold (51% of total recovery in 2010) with Diester table upgrading to 75% gold concentrate
- Cyanidation/CIP: Four-tank leach circuit with carbon adsorption, elution, and electrowinning producing cathode sludge for direct smelting
- Flotation: Outotec flotation cells (4x 30m³) recover refractory gold locked in sulphides, producing concentrate grading up to 6 oz/st Au
- Pressure Oxidation: Five-compartment autoclave (71 t/d capacity) treats refractory concentrates at 75°C with 48-hour retention
- Paste Fill: Tailings dewatered through disc filters, mixed with cement/fly ash, and pumped underground as backfill
- Effluent Treatment: Multi-stage system including polishing ponds and 16ha constructed wetland achieving 85% ammonia reduction
Critical Data
| Parameter | Value |
|---|---|
| Red Lake Throughput | 1,250 t/d (permitted) |
| Campbell Throughput | 1,800 t/d |
| Grind Size (P80) | 65-75 μm |
| Energy Consumption | 74 kWh/t |
| Gravity Recovery (2010) | 265,641 oz (51% of total) |
| Flotation Concentrate Grade | Up to 6 oz/st Au |
| Autoclave Capacity | 71 t/d concentrate |
Circuit Highlights
The integrated flowsheet handles three gold types: coarse free-milling (gravity), fine free-milling (cyanidation), and refractory (flotation+POX). The 2007 verti-mill installation increased grinding capacity, while the paste fill plant optimizes tailings management with 50% of material used as underground backfill. The Campbell autoclave (converted from roaster in 1991) achieves high recoveries through precise control of temperature (75°C), pressure (480 kPa), and acid pre-treatment (pH ≤3.0).
