I. East Africa (Mainly Gold Mining)

1. Gold Mine in the Lake Victoria Greenstone Belt, Tanzania

(High-Efficiency Wire-Line Coring Exploration)

• Project Overview:Gold deposit in the greenstone belt around Lake Victoria. Designed 7 holes with total depth of 2,500 m; actually completed 12 holes with total depth of 3,201.2 m. A single rig set a high-production record within 5 months.

• Rig & Technology:Full hydraulic wire-line coring rig (XY‑6 / ROCK series), HQ/NQ wire-line coring tools, impregnated diamond bits.

• Key Advantages:Wire-line coring without tripping drill rods; suitable for hard rock and fractured alteration zones. Core recovery rate ≥ 90%. Average monthly footage per rig exceeds 600 m, with efficiency over 40% higher than conventional drilling.

• Achievements:Multiple quartz‑vein type gold orebodies were delineated, and Class 333 gold resources were submitted, supporting subsequent development.

2. Zara Gold Mine, Eritrea

(High‑Angle Inclined Holes + Complex Formations)

• Project Overview:Located in the Sahelian mountainous area with rugged terrain and poor transportation. Designed inclined holes with dip angle of 45°–55°, hole depth 200–500 m in the main mining area, total workload 11,000 m.

• Rig & Technology:Full hydraulic wire-line coring rig, Q‑series wire-line coring system, anti-deviation drill assembly, high‑viscosity mud for wall protection.

• Technical Challenges:Deviation control in high‑angle inclined holes, “slippage” in hard rock, high temperature and drought, borehole wall collapse.

• Solutions:Optimized weight on bit / rotating speed, centralizers for anti-deviation, special mud formula, wire-line coring to reduce tripping.

• Achievements:All inclined holes completed. Core recovery rate ≥ 92%, hole deviation accurately controlled ≤ 1°/100 m. Deep blind orebodies successfully delineated.