Over 200 kg of explosive dynamite were used Friday 21st April at the BBT construction site in Mules to break out the first 1.5 m of rock (corresponding to 120 m3 of material), thus opening the last excavation front. Starting in December of 2016, five excavation fronts had been opened as part of the Mules 2-3 construction lot:
- on December 6th, the access tunnel to the future emergency stop in Trens (3.8 km long);
- on February 13th, the exploratory tunnel northwards (14.8 km long);
- on March 13th, the main west tube towards the Brenner (15 km long);
- on March 16th, the main east tube towards the Brenner (15 km long);
- on April 3rd, the main west tube moving southwards (4.9 km long).
Including yesterday’s work, there are now six excavation fronts, four driving northwards and two southwards. The Mules 2-3 lot, which is worth 993 million Euro, includes 39.8 km of main tunnels, 14.8 km of exploratory tunnel and 10.2 km of logistics and safety tunnels, for a total of about 65 km of tunnels. So far, more than 400 m have been completed.
Excavation methods
All excavation work will be initially carried out using the “drill and blast” system, meaning with explosives and digging machines, but once driven through the important geological fault line known as the Periadriatic Fault, tunnel boring machines (TBMs) will also be used. The first should begin work towards the end of 2017. The work on this lot is expected to end in 2022, when the tunnels reach the border.
