Gas Migration in EBS and Geosphere (GMT) - Initial Conclusions

The reporting phase of the Gas Migration Test is currently underway, once completed, copies of the GMT reports can be obtained from Nagra here.

Some initial conclusions can be drawn from the project:


  • Visual inspection shows that buffer is unaltered from construction
  • Uniform bentonite content indicates no segregation after emplacement.
  • Mineralogical content was consistent with that emplaced.
  • No dominant water flow direction was observed
  • No lateral variability in density, porosity or water content was seen in the geophysical logs.
  • Directional logging did not show any high-porosity channels.
  • Dry density typically increased indicating some small additional compaction after emplacement.
  • Concrete silo and vent showed no evidence of damage or alteration.


The GTS underground facilities are also available to interested 3rd parties for underground testing and research. The GTS offers cost-effective access to a fully developed, well characterised underground research facility with round the year logistical support - please contact Dr. Ingo Blechschmidt, Head of the Grimsel Test Site, for further details.