Borehole Drilling
Modern drilling equipment and experienced crews delivering quality boreholes for domestic, commercial, and industrial water supply needs.
DTH Drilling Rig
Drilling Expertise
Unihydro Limited utilizes modern Down-The-Hole (DTH) drilling machines capable of penetrating various geological formations. Our drilling methodology ensures borehole stability, optimal water yield, and long-term sustainability.
We conduct both Direct Rotary Air drilling and Mud drilling, selecting the most appropriate method based on geological conditions and project requirements.
Drilling Methods
Direct Rotary Air Drilling
Uses compressed air to remove cuttings and cool the bit. Ideal for hard rock formations and consolidated materials.
- • Fast penetration in hard rock
- • Excellent sample quality
- • Good for deep boreholes
- • Minimal formation damage
Mud Rotary Drilling
Uses drilling fluid (mud) to stabilize the borehole and remove cuttings. Suitable for unconsolidated formations and loose soils.
- • Borehole stability in loose soils
- • Prevents caving in unconsolidated layers
- • Good for alluvial deposits
- • Enables continuous sampling
Borehole Specifications
8"
Drilled Diameter
203.2 mm
Sufficient annulus for gravel pack
6"
Casing Diameter
152.4 mm
uPVC Class E / Black Steel Class B
Depth Capability
Our equipment can drill to depths of up to 350 meters, depending on geological conditions.
- • Standard depth: 50-150m
- • Deep boreholes: 150-300m
- • Maximum: 350m
Screen Specifications
- • Slot size: 0.5mm
- • Minimum open area: 12.5%
- • Material: Stainless steel / uPVC
- • Length: 6m sections standard
- • Connections: Flush welded/threaded
Quality Control Procedures
Formation Sampling
Samples collected every 2 meters or at every change of formation. Additional samples taken at water strikes and significant geological changes.
Water Strike Recording
Upon encountering water, drilling ceases for 30 minutes to record static water level. Yield estimates conducted every 10m.
Daily Reporting
Comprehensive daily logs including depth, penetration rate, water levels, samples taken, and equipment used.
Casing Installation
Casings pass easily into borehole under their own weight. No force used. Reaming conducted if necessary at contractor expense.
Filter Gravel Pack
We use high-quality quartzitic/silica gravel pack material (0.6-1.4mm grade) installed via tremie pipe to ensure proper formation stabilization.
- ✓ 90%+ siliceous materials
- ✓ No clay, organics, or shale
- ✓ Naturally rounded particles
- ✓ 6m coverage above top screen
- ✓ 1m sand seal above gravel
- ✓ 2m bentonite clay seal
Borehole Construction Layers
Borehole Construction Details
Ready to Drill?
Contact us for a quotation. We provide complete drilling services from site preparation to borehole completion and handover.
Request Quote