Configuration and Set up before drilling

Drill string configuration for accurate drilling

The drill string consist of (from the bottom and upwards)

- Pilot bit, threaded into a sub containing a one-way water valve.
- Three stabilizers, after each other.
- Two drill rods, after each other.
- One stabilizer.
- Sufficient numbers of drill rods, required to complete the pilot hole.

Set up before drilling

1. A concrete slab is cast on a clean and well scaled rock surface.

2. Two foundations beams (supplied by Bergteamet) are placed and positioned on the concrete slab. Each beam is held with ten anchor bolts, diameter 25 mm with a length of 1,6 m, grouted into the solid rock.

3. The raise boring machine is transported to the drillsite by own diesel driven crawler unit or carried by wheel loader or Toro and then mounted on the beams and erected. The initial drilling direction is adjusted in one direction with help of adjustable spanners and in the other direction with help of shims placed between the foundation beams and the concrete slab.

4. Before starting the pilot hole drilling the initial drilling direction is controlled and all anchor bolts are tightened.

5. Water re-circulation dams for sedimentation of pilot hole flushing water is setup within 50 meter to the drillsite by the Client. Normal use of water is 20-40 m3 and a re-fill capacity of approximate 450 l/min. Pumps for circulation are included in our equipment at arrival to site.

6. Electrical assistance for connecting our powerpacs and surveyor to set the machine in the right dip and azimuth angles.