Project Overview
The Cambodia Mondulkiri Mine Heap Leaching & Tailing Project processes gold oxide ore (1.8 g/t Au) from the Cardamom Mountains through conventional heap leach technology. WSHT Mining Group designed the complete facility including heap leach pad, solution management, ADR gold recovery, and engineered tailings storage facility (TSF).
Ore Characteristics
The oxide ore is weathered laterite capping overlying primary sulfide mineralization. Gold occurs as fine free particles (60%) and colloidal gold adsorbed on iron oxides (40%). The ore is soft (Bond Work Index 8.5 kWh/t) and amenable to run-of-mine or crush-only heap leaching with 80% passing 25 mm.
Process Flow
Crushing: ROM ore is scalped at 500 mm and fed to a C100 jaw crusher via a vibrating grizzly. Product (−100 mm) is conveyored to the heap leach pad. Two-stage crushing (jaw + cone) produces −25 mm material for improved leach kinetics. Total crushing capacity: 80 t/h.
Heap Leach Pad: A 120 m × 80 m heap leach pad is constructed with double-lined HDPE geomembrane (1.5 mm + 1.0 mm) over compacted clay. Crushed ore is stacked in 8 m lifts by a CAT 980F wheel loader. Cyanide solution (0.05% NaCN, pH 10.5) is irrigulated at 10 L/m²/h through drip emitters. Leach cycle: 90 days per lift.
Gold Recovery: Pregnant leach solution (PLS, 2-4 g/m³ Au) is pumped to a three-stage carbon adsorption circuit (3× Φ2.5×5 m columns, 40 m³ each). Loaded carbon is stripped in a 3-stage ADR elution circuit, electrowon, and smelted to doré bars.
Tailings: Spent ore is rehandled to an engineered TSF with 100,000 m³ design capacity. The TSF features HDPE liner, decant tower, and return water collection system.
Key Equipment
| Equipment | Specification | Capacity |
|---|---|---|
| C100 Jaw Crusher | 1000×650 mm feed opening | 80-150 t/h |
| HP200 Cone Crusher | Secondary crushing | 50-100 t/h |
| Heap Leach Pad | 120 m × 80 m, double-lined | 500 TPD |
| 3× Carbon Columns | Φ2.5×5 m, 40 m³ each | PLS adsorption |
| ADR Elution Circuit | 3-stage, Zadra process | 10 t carbon |
| Electrowinning Cell | 12 cathodes, stainless | 25 kg Au/day |
| TSF | 100,000 m³, HDPE lined | Tailings storage |
| Drip Irrigation System | Pressure-compensating | 10 L/m²/h |
Project Highlights
- Capacity: 500 TPD heap leach (150,000 TPA)
- Gold Recovery: 75-80% from oxide ore
- Pad Area: 9,600 m² (expandable to 25,000 m²)
- Heap Height: 8 m per lift, 3 lifts planned
- Cyanide Consumption: 0.3 kg/t ore
- Water Balance: 60% evaporation loss makeup
- Timeline: 12 months EPC delivery
- Location: Mondulkiri Province, Cambodia
