Overview
The Madsen Mine in Ontario, Canada, operates a sophisticated gold processing plant capable of achieving 95.7% gold recovery through a combination of gravity concentration, cyanide leaching, and carbon adsorption. The facility processes 800 tonnes per day (tpd) of ore from five distinct lenses, delivering gold doré bars on-site.
Key Process Stages
- Primary Crushing: Semi-mobile jaw crusher reduces ROM feed (F100: 500 mm) to P80 of 75 mm
- Grinding: SAG mill (4.9m x 1.5m, 560 kW) and ball mill (2.9m x 4.9m, 560 kW) achieve final P80 of 75 µm
- Gravity Concentration: Two semi-continuous concentrators recover free gold from SAG/ball mill discharge
- Pre-Oxidation: Oxygen-sparged agitation tank (2-hour retention) optimizes leaching conditions
- Cyanide Leaching: Five tanks (24-hour retention) operate at 150-170 ppm NaCN and pH 11.0
- CIP Adsorption: Six-tank circuit (5-hour retention) with carbon concentration of 25-50 g/L
- Carbon Processing: Acid wash (3% HCl), pressurized elution (140°C, 450 kPa), and thermal regeneration
- Electrowinning: Dual-circuit system processes strip solution and intensive leach concentrate
- Cyanide Destruction: SO2/oxygen process reduces CNWAD to <5 mg/L in agitated tanks
Critical Data
| Parameter | Value | Source |
|---|---|---|
| Throughput | 800 tpd | SRK Mine Plan |
| Gold Recovery | 95.7% | BaseMet Testwork (BL288) |
| Bond Ball Mill Work Index | 9.7-17.1 kWh/t | BaseMet (2018, 2023) |
| Leach Retention Time | 24 hours | Operational Data |
| CIP Carbon Load | 3,310 g Au/t | Vendor Model |
| NaCN Consumption | 152 t/yr | BaseMet (2018) |
Innovations
The plant features oxygen injection in pre-oxidation and leach circuits to enhance metallurgical performance, along with a hydraulic backfill system for tailings management starting in Year 1. The carbon regeneration kiln processes 1 tpd of activated carbon with integrated heat recovery.
Based on filing data from 2024-2025.
