Overview
The Panuco processing plant is designed to treat mineralized material through a phased approach, initially employing whole ore cyanide leaching (Years 1-3) before transitioning to bulk flotation with concentrate regrind and leaching (Year 4+). The plant operates with two 12-hour shifts daily at 92% availability for most circuits, processing 1.2 Mt/a in Phase 1 and expanding to 1.5 Mt/a in Phase 2.
Key Process Stages
- Phase 1 (Years 1-3): Three-stage crushing → Ball milling → Whole ore cyanide leaching → Merrill Crowe recovery
- Phase 2 (Year 4+): Bulk flotation added → Concentrate regrind → Separate concentrate and tailings leaching circuits
- Crushing: ROM feed (F80 265mm) reduced to P80 9mm via jaw crusher + two cone crushers
- Grinding: Ball mill in closed circuit with cyclones producing P80 70µm
- Leaching: 96-hour residence for whole ore (Phase 1), 48-hour for concentrate + 72-hour for tailings (Phase 2)
- Gold Recovery: Merrill Crowe zinc precipitation producing doré bars
- Tailings: Cyanide detoxification (SO2/air process) followed by thickening for TSF or paste backfill
Critical Data
| Parameter | Phase 1 | Phase 2 |
|---|---|---|
| Throughput | 1.2 Mt/a | 1.5 Mt/a |
| Crushing Availability | 65% | 65% |
| Grinding P80 | 70 µm | 70 µm |
| Bond Ball Mill Work Index | 18.3 kWh/t | 18.3 kWh/t |
| Leach Residence Time | 96 hours | 48h concentrate + 72h tailings |
| Installed Power | 5.4 MW | 6.1 MW |
| Annual Lime Consumption | 2,020 t | 2,152 t |
| Annual Cyanide Consumption | 1,200 t | 1,295 t |
Circuit Components
Crushing
- Vibrating grizzly + static screen
- Primary jaw crusher
- Secondary & tertiary cone crushers
- 9mm product sizing
Grinding
- Ball mill with cyclone classification
- 400% circulating load
- 35% solids in cyclone overflow
Leaching
- Oxygen sparging system
- Lime for pH control (target pH 10.5-11)
- 5-stage CCD washing circuit
Reagents
- Collector: Potassium amyl xanthate (PAX)
- Frother: Methyl isobutyl carbinol (MIBC)
- Cyanide destruction: SO2/air with Cu catalyst
Based on filing data from 2024-2025.
