Project Overview
The Papua New Guinea Bougainville Province Hydrometallurgical Leaching Plant processes secondary copper-gold ore from the Panguna mine tailings. WSHT Mining Group designed a complete hydrometallurgical facility producing LME Grade A copper cathode with gold recovery from leach residues.
Ore Characteristics
The feed material is historical mine tailings containing 0.9% Cu (oxide) and 0.4 g/t Au. Copper occurs as chrysocolla, malachite, and minor chalcocite. Gold is fine-grained and associated with iron oxide gangue. The material is free-digging and requires minimal crushing.
Process Flow
Material Handling: Historical tailings are excavated by excavator and transported by 30-t rigid haul trucks to the agglomeration plant. No primary crushing required due to fine particle size of tailings feed.
Agglomeration & Heap Leach: Tailings are mixed with cement (20 kg/t) and sulfuric acid (5 kg/t) in a rotary drum agglomerator, then stacked on a 100 m × 80 m heap pad. Leach cycle: 60 days. PLS copper concentration: 4-6 g/L Cu.
SX-EW: PLS is processed through a 2-stage mixer-settler SX circuit (LIX 984N organic). Strip solution feeds a 200-cathode EW plant. Current density: 280 A/m². Cathode purity: 99.99% Cu (LME Grade A).
Gold Recovery: Spent heap leach residue is repulped and processed through a CIL circuit (4 tanks × 80 m³) for residual gold recovery. Gold recovery from residue: 45-50%.
Key Equipment
| Equipment | Specification | Capacity |
|---|---|---|
| CAT 390F Excavator | Material handling | 300 t/h |
| 3× 30t Haul Trucks | Rigid frame, off-road | Transport |
| Rotary Agglomerator | Φ2.0×6 m, 50 t/h | Cement mixing |
| Heap Leach Pad | 100 m × 80 m, HDPE lined | 500 TPD |
| 2-Stage SX Circuit | Mixer-settlers, LIX 984N | Cu extraction |
| 200-Cell EW Plant | Stainless cathodes | Copper cathode |
| 4× CIL Tanks | 5.0 m dia × 4.5 m, 80 m³ | Gold from residue |
| Tailings Residue Dam | 50,000 m³, lined | Spent residue |
Project Highlights
- Capacity: 500 TPD tailings processing
- Copper Production: 6,000 TPA LME Grade A cathode
- Gold Recovery: 45-50% from leach residue
- Heap Area: 8,000 m² (expandable)
- Acid Consumption: 25 kg/t (cement neutralization)
- Power: 2.5 MW (diesel generators)
- Timeline: 14 months EPC delivery
- Location: Bougainville Province, PNG
