Overview
La Colorada is an open pit gold-silver mine in Sonora, Mexico featuring a 12,000 t/d heap leach operation with carbon adsorption recovery. The facility processes ore through three-stage crushing, heap leaching, and a carbon-in-column adsorption circuit to produce doré bars.
Key Process Stages
- Crushing Circuit: Three-stage crushing to P80 9.5 mm (3/8″)
- Primary: 44″ x 50″ jaw crusher reduces ROM to -250 mm
- Secondary: Two standard cone crushers at 25 mm CSS
- Tertiary: Four short head cone crushers in closed circuit
- Heap Leaching:
- 10m lifts leached for 90 days with 450 ppm NaCN solution
- 10 L/h/m² application rate via drip irrigation
- Lime addition (2-3 kg/t) maintains pH at 10.5
- Double-lined HDPE leach pad with leak detection
- Carbon Adsorption:
- 750 m³/hr cascade carbon-in-column circuit (5 columns)
- Carbon loads to ~5,000 g/t Au+Ag
- Metal Recovery:
- Pressure Zadra stripping at 135°C/450 kPa
- Electro-winning with two electrolytic cells
- Carbon regenerated every 3 cycles at 750°C
- Separate circuit processes carbon from El Castillo/San Agustin mines
Critical Data
| Parameter | Value |
|---|---|
| Throughput | 12,000 t/d |
| Crushing Product Size | P80 9.5 mm |
| Leach Cycle | 90 days |
| Gold Recovery | 67.6% (historical) |
| Silver Recovery | 10.6% (historical) |
| Carbon Loading | ~5,000 g/t Au+Ag |
| ADS Flowrate | 750 m³/hr |
| Cyanide Consumption | 0.5-0.6 kg/t |
| Lime Consumption | 2-3.4 kg/t |
Operational Notes
The facility maintains approximately 15,166 oz Au in inventory (heap, carbon, and solutions). Recent processing of high-grade El Crestón ore (>5 g/t Au) showed slower recovery rates potentially due to coarse gold and electrum presence. The operation includes a mercury retort system for processing San Agustin carbon.
