Overview
The Casa Berardi Mine operates a gold processing facility using a Carbon-in-Leach (CIL) circuit to counteract preg-robbing effects from graphitic carbon in the ore. The plant, operational since 2019, integrates crushing, grinding, gravity concentration, and cyanide leaching to achieve an average gold recovery of 86.7%.
Key Process Stages
- Crushing: Ore passes through a grizzly screen, jaw crusher (762mm x 1400mm), and 3,000-tonne storage bin.
- Grinding: SAG mill (5.5m x 2.7m, 1,130 kW) and ball mill (4.0m x 5.3m, 1,325 kW) achieve a P80 of 91.5 µm.
- Gravity Circuit: Two Knelson concentrators (762mm) recover 36.5% of gold, with concentrate processed in an intensive leach reactor (Gekko ILR).
- CIL Circuit: Seven 700m³ tanks with 20-hour residence time, 24 g/L carbon concentration, and 450 ppm NaCN.
- Elution & Electrowinning: ZADRA process at 135°C/380 kPa produces gold sludge smelted into doré bars.
Critical Data
| Parameter | Value | Unit |
|---|---|---|
| Throughput | 1.4 | Mt/a |
| Feed Grade | 2.8 | g/t Au |
| Grinding P80 | 91.5 | µm |
| Cyanide Consumption | 0.55 | kg/t |
| Carbon Concentration | 24 | g/L |
Recent Upgrades
Key 2017-2018 optimizations included SAG mill liner redesign, ball size adjustments (125mm), and increased discharge grate area (4.0%). These raised throughput from 1.2 Mt/a (2015) to 1.4 Mt/a (2019).
