Overview
The Hope Bay processing facility utilizes a complex circuit combining gravity concentration, flotation, and cyanide leaching to recover gold from sulphide ore. The plant originally operated with one concentrating line (CL1) and was later expanded to include CL2, achieving a blended throughput of 51.1 t/h in 2019.
Key Process Stages
- Crushing Circuit: Three-stage crushing with Metso Nordberg C100 primary jaw crusher (P95 125mm), Metso C80 secondary crusher, and Remco 1530 VSI tertiary crushers
- Gravity Concentration: Falcon SB1350B batch concentrators (200G force) and Falcon C2000 continuous concentrators recovering 60-70% of gold
- Grinding: Outotec 15-04 ball mill (2.7m x 4.88m EGL, 450kW) in closed circuit with Cavex 250CVX20 cyclones (P80 150µm target)
- Flotation: Nine 5m³ Metso RCS-5 cells with PAX collector, achieving 15% mass pull at 90% recovery
- Intensive Leaching: Gekko ILR 2000 batch reactors (12-16hr cycles) with 98.5% recovery at 20% CN- concentration
- Continuous Leaching: Six horizontal CILR vessels with 30hr retention time at 5,000-6,000 mg/L CN-
- Resin Adsorption: G-Rex columns with AuRIX®100 or Purogold™ MTA9920 resin achieving 2,100-2,800 mg/L loading
Critical Data
| Parameter | Design | 2019 Actual |
|---|---|---|
| Throughput (t/h) | 55 (Doris), 43 (Naartok) | 51.1 (blended) |
| Overall Recovery | 96.8% | 81.6-84.7% |
| Gravity Recovery | 69.4% | 60-65% |
| Flotation Tail Grade | 0.36 g/t | 0.93 g/t |
| Leach Residue Grade | 6.9 g/t | 9.3 g/t |
| Ore SG | 2.8 | |
Madrid Expansion
The new Madrid plant (2020) features a 4,000 t/d SABC circuit with:
- Single-stage primary crushing to P80 100mm
- Gravity concentration and intensive cyanidation
- 30-hour CIL circuit with carousel operation
- 88% projected LOM recovery
- 1,460,000 t/a capacity
