Ultimately Visser & Smit Hanab undertook all four drillings in this complex project. For each of the four drillings a separate hole was first drilled, parallel to the actual drilling. Here an 8" pipe was drawn down that during the drilling was also utilised as a mud return pipe. After completion it was used as a pipe sleeve for a fibreglass cable.
During the initial drillings some boulders of considerable size were encountered underground. Thanks to a stone catcher especially designed by Visser & Smit Hanab, these
stones could be scooped out of the drill hole relatively easily, and the works resumed.
In view of the soil condition and the time specifications this was an enormous challenge. In addition, a great amount of prestige was at stake. In spite of all these factors and the external pressure, the deadline was effortlessly met.