Principle and application
Where SPT percussion stops, rotary drilling carries on. It penetrates rock and very hard soils, recovering the continuous core that reveals fractures, rock mass quality and the founding level for foundations.
The test, step by step
Rotary drilling
The string rotates with a diamond bit, cutting the rock by abrasion under water circulation.
Core recovery
The core barrel recovers the continuous core of the rock mass on every run.
Logging and RQD
Recovery and RQD are measured, both indicators of rock quality.
Core storage
The core is arranged in boxes labelled by depth.
The test in the field
What rotary drilling measures
| Core | Continuous sample of rock or hard soil |
|---|---|
| RQD | Rock quality designation index |
| Recovery | Percentage recovered per run |
| Fracturing | Degree and orientation of discontinuities |
Quality and field operation
Data quality
- Bits and core barrels suited to the rock mass.
- Recovery and RQD control on every run.
- Core photographed and boxes labelled.
- Geological description by a qualified professional.
Safety and operation
- Ready for high-demand environments: mining, industry and ports.
- Organised, signed work front with an HSE procedure in place.
- Own crews and fleet, including night shifts.
The deliverable
| Drilling log | Profile with recovery, RQD and rock mass description |
|---|---|
| Core boxes | Arranged and photographed by depth |
| Founding level | Indication of rock head or hard layer |
| Typical turnaround | According to depth and hardness of the rock mass |
Sectors and project types
Frequently asked questions about the Rotary core drilling
What is rotary core drilling in rock for?
Where SPT percussion stops, rotary drilling carries on. It penetrates rock and very hard soils, recovering the continuous core that reveals fractures, rock mass quality and the founding level for foundations.
What is RQD?
Rock Quality Designation: the sum of the core pieces longer than 10 cm, divided by the length drilled. It is the classic indicator of rock mass quality.
Are rotary core drilling and composite drilling the same thing?
No. Composite drilling starts with percussion (SPT) in the soil and switches to rotary drilling when it reaches rock, combining both methods in the same borehole. Rotary drilling is the phase that drills and recovers core from the rock.
Rotary core drilling in rock for your project
Tell us the project context, we will put together the investigation plan and the quote.