The excavation, which was completed on December 15, 2022, involved the challenging task of digging through difficult geological conditions, including tectonized metamorphic formations of carbonaceous phyllites, quartzitic phyllites, and gneiss, with a maximum overburden of 1000 meters.
To ensure safety, the tunnel will be equipped with a mechanical longitudinal ventilation system and an air lock system in the escape tunnel to keep rescue passages free from smoke in the event of a fire. The main tunnel will also have an air quality measurement system to control ventilation during normal operation, and a tunnel monitoring and control system to automatically activate fire programs in the event of an accident.
