Clay core sampling

Many experiments have been installed in HADES to investigate the behaviour and properties of Boom Clay. In order to install these experiments, EURIDICE technicians make a cylindrical borehole in the clay into which researchers place measuring instruments. To make this opening, the relatively soft clay is crushed into small pieces by a drill head with a series of teeth. In this way, boreholes with a diameter of fifteen centimetres are made in the clay, sometimes up to 40 metres deep.

However, an important part of the research takes place in above-ground laboratories. Scientists of SCK CEN or other research institutes study the mechanical behaviour of clay in specially designed test set-ups or measure the migration rate of radionuclides in clay in a more controlled environment. For these above-ground tests, Boom Clay samples are needed that are disturbed as little as possible. EURIDICE's technical team takes these samples by means of so-called “core drillings”.  

Drill head Drill head core sampling

Drill head for making boreholes

Drill head for core drillings

A “core drilling” is intended to extract undisturbed, cylindrical cores from clay. In this case, the technicians use a hollow, double-walled drill rod. The outer wall is equipped with teeth that leave a clay core. The inner wall slides systematically over the intact clay core until the clay core has a length of about 1 metre. The double-walled drill rod with the clay core is then removed from the borehole. The metal inner wall is opened, the core is removed and packed airtight to protect the clay from oxidation.


Watch the movie below about clay core extraction in HADES!