In connection with the reconstruction and new building project for the Cantonal High School in Heerbrugg (St. Gallen, Switzerland) a geothermal energy probe field will come into operation. After we had the opportunity to conduct an energy simulation for the probe field in 2010, the drilling work is now (summer of 2012) in progress with 2 parallel working drilling machines. The probe field consists of 67 geothermal probes of 150 m depth and are 7 m apart. Duplex probes with a diameter of 40 mm will be used. The probes will serve as heating and cooling system for the school. As expected the bedrock runs in very alternating depths between approx. 70 and 140 m below surface.