Geonor has carried out more than 6,000 m of horizontal boreholes dedicated to geotechnical surveys.

The evolution in the underground mining market has been the direct consequence of the recent appearance of high-power electric core recovery probes (borehole lengths between 800 and 1,000 metres).

This equipment, in addition to its usefulness in mining research, opens up a very important range of possibilities from the point of view of geotechnical research focused on underground infrastructures.

With this type of probes, which are very versatile and easy to set up in the field, it is possible to carry out horizontal or steeply inclined reconnaissance probes, which make it possible to investigate infrastructures such as tunnels, tunnels, dams, etc., which until now had been studied by means of costly geotechnical campaigns of vertical development, in which very limited information was obtained from the terrain and which were subject to interpretation.

  • The probe frame allows soundings to be carried out in any orientation and inclination (including negative inclination soundings - ascending), up to depths / lengths between 800 and 1,000 metres.
  • Borings are carried out by rotation with water circulation, with continuous core recovery and in varying diameters, generally between HQ and NQ (core diameter varying between 63.5 and 47.6 mm, respectively).
  • Both the length and the deviation of a borehole are therefore highly conditioned by the terrain to be drilled, so these lengths and deviations will be those permitted by the existing technology.
  • A REFLEX® gyroscope can be used to measure borehole deviation, which allows measurements to be taken in all types of magnetic and non-magnetic environments, even inside the drill string.

In Spain, GEONOR is the company that has carried out the greatest amount of this type of drilling in geotechnical studies and during the execution of civil works.