Project Overview
The Zimbabwe Kraton Ball Milling Processing Line is designed for gold ore processing in the Matabeleland gold belt. WSHT Mining Group delivered a robust crushing, grinding, gravity concentration, and CIL circuit optimized for remote African mining operations with limited infrastructure.
Ore Characteristics
The ore is a quartz vein-hosted gold deposit with coarse free gold (60% liberated at 150 microns) and fine disseminated gold in pyrite (40%). Average grade: 5.2 g/t Au. Ore competency is moderate (Bond Work Index 12.8 kWh/t). The high free gold content makes gravity concentration highly effective as a pre-concentration step.
Process Flow
Crushing: ROM ore (−400 mm) passes through a PE-750×1060 jaw crusher (primary, 130-250 t/h) and a HPT-300 cone crusher (secondary) to produce P80 = 12 mm product. A 2YK-1860 vibrating screen provides classification with oversize recirculation.
Grinding: Crushed ore is fed to a Φ3.2×4.5 m overflow ball mill (1,500 kW, manganese steel liners) operating in closed circuit with 6× NX300 hydrocyclones. Target grind: 80% passing 75 microns. Mill throughput: 40 t/h at 68% solids.
Gravity Concentration: Mill discharge is classified on a vibrating screen at 150 microns. Coarse fraction reports to a Falcon SB-400 centrifugal concentrator for free gold recovery. Concentrate is upgraded on a Gemini CT-1000 shaking table and smelted on-site. Gravity recovers 65-70% of coarse gold.
CIL Circuit: Fine fraction from gravity circuit reports to 6 CIL tanks (4.5 m diameter × 5.0 m height, 80 m³ each). Cyanide leaching at 250 ppm NaCN, pH 10.5. Residence time: 24 hours. Carbon loading: 15 g/L. Gold recovery: 92-94% total (gravity + CIL).
Key Equipment
| Equipment | Specification | Capacity |
|---|---|---|
| PE-750×1060 Jaw Crusher | Primary, 130-250 t/h | 130-250 t/h |
| HPT-300 Cone Crusher | Secondary, hydraulic | 80-180 t/h |
| 2YK-1860 Vibrating Screen | Double-deck, 1800×6000 | 150-300 t/h |
| Φ3.2×4.5 m Ball Mill | 1,500 kW, Mn steel liners | 40 t/h |
| 6× NX300 Hydrocyclones | Classification cluster | 40 t/h total |
| Falcon SB-400 Concentrator | Centrifugal, 100 t/h | Free gold recovery |
| Gemini CT-1000 Table | Shaking table | Concentrate upgrading |
| 6× CIL Tanks | 4.5 m dia × 5.0 m, 80 m³ | 24 h residence |
Project Highlights
- Capacity: 800 TPD (240,000 TPA) gold ore
- Total Recovery: 92-94% (gravity + CIL)
- Gravity Recovery: 65-70% of free gold
- Power: 3.5 MW (diesel generator backup)
- Water: 80% recycling, 2.5 m³/t ore
- Remote Operation: Self-sufficient camp facility
- Timeline: 14 months EPC delivery
- Location: Kraton, Matabeleland, Zimbabwe
