In the last twelve months, the works for the Wolf access tunnel were completed. This tunnel runs 3,600 metres deep into the mountain to a 280 m² junction chamber; from here, an access ramp leads straight to the exploratory tunnel. A further connecting tunnel will in future link the Wolf access tunnel to both the main tubes. Works on this tunnel are under way at present.
In 2015, workers excavated 2,002 metres of the Wolf access tunnel by blasting. Based on the Austrian tunnel construction method, the upper third of the tunnel (the crown or heading) was excavated first and then the middle and lower sections (the bench and the base), blasting metre by metre. On average, the miners advanced about 6 metres per day. The costs for the works were about 30 million Euro in 2015. Besides this, about 900,000 Euro were used for services, such as local construction supervision, geotechnical measurements, executive planning including the activities of a geotechnician on-site or a construction site coordinator.
Preliminary crushing of the spoil takes place inside the tunnel itself, in a special chamber. After this it is taken to the Padaster valley disposal site for further processing and the surplus material is permanently disposed of there. Using an innovative process to treat low-grade Bündner schists, BBT SE and its partners succeeded in producing a total of 136,000 tons of aggregates for concrete and 120,000 tons of drainage gravel. This means that 100% of the aggregates used in the production of concrete for the Wolf construction site over the past twelve months came from this plant. This cuts down on resource consumption, on the volume of material to be deposited and on transportation. 260,000 m³ of spoil were deposited in 2015.