Exploratory Tunnel Višňové1998-2002

Length of the tunnel 7.48 km. The exploratory tunnel is located in the center profile of the southern tunnel tube of the main tunnel and after being perforated it will be constructed into an escape tunnel for the tunnel passing through the northern tube. From the side of the wester portal - from the village of Višňové - it was tunneled using the classic NATM method. On a 3.118 km long section 42 700 m³ of spoil were tunneled out, of which 8 200 m³ were tunneled uphill and 34 500 m³ were tunneled downhill. From the eastern side - from Dubná Skala - tunneling was carried out continuously based on the estimated geology. The tunneling was carried out using a complex mechanized tunneling device ATB 35 HA with a drilling head with the diameter of 3.5 m. On a 4.362 km long section 42 000 m³ of spoil were tunneled out.