Geological core drilling rigs
Rigs for wireline core drilling in HQ, NQ, PQ and BQ sizes.
Core rigs run at high speed with precise load control to bring up intact core. Wireline lets the inner tube be retrieved without pulling the rod string. These rigs are for companies working in mineral and construction-materials exploration, site investigation and hydrogeology.
How they differ from water-well rigs
A water-well rig is built to open a large hole quickly. A core rig's job is to cut the rock with a small-diameter diamond bit and bring up whole core. So it turns faster, controls the weight on the bit precisely and carries a dedicated winch for retrieving the inner tube.
How wireline works
The inner tube sits inside the rod string, just above the bit. When it is full, drilling stops, an overshot on a cable is lowered down the rods, latches onto the inner tube and brings it up. Once the core is removed, the empty tube is sent back down. Throughout, the rods stay in the hole and protect its walls. The whole string only has to be pulled to change the bit.
Key figures
A core rig's depth rating is given per core size: the smaller the size, the deeper it goes. An indicative example for a mid-sized rig:
| Size | Depth rating (example) |
|---|---|
| BQ | up to 1000 m |
| NQ | up to 800 m |
| HQ | up to 600 m |
| PQ | up to 350 m |
Other key figures are pull-back capacity, rotary head speed and torque, the angle range for inclined holes and the wireline winch's cable capacity.
Choosing a rig
- Depth and size. The project's deepest hole and largest core size set the rig class.
- Inclined holes. Mineral exploration often drills at an angle, so the mast must set to the angle you need.
- Terrain. Crawler or modular rigs suit mountains and remote sites; truck-mounted rigs suit jobs near roads.
- Water supply. Core drilling needs water, so haulage and recycling must be planned.
What else you need
Besides the rig, you need diamond bits, reaming shells, core barrels, an overshot, drill rods, a mud pump and core boxes, all in one size. This equipment is listed by size under “Geological equipment”.
When you get in touch, tell us the purpose of the project, the hole depths and core size, whether you need inclined holes and what the site conditions are.