TELT has gathered the main questions from the local area regarding the planned activities in the Susa Plain, particularly concerning the logistics of the construction sites and the management of excavation materials for the Mont Cenis base tunnel.
1. Where will the excavated material from the Lyon-Turin base tunnel be processed in Italy?
The primary site for the reuse and processing of excavation materials on the Italian side of the base tunnel is Salbertrand. Covering approximately 110,000 square metres and located near the A32 motorway and railway, this area had previously been used for the uncontrolled deposit of various materials, including potentially polluting waste, by companies that never arranged for their removal. TELT took on the task of resolving this long-standing issue and, in September 2024, completed the safe removal of around 222,000 tonnes of waste, including construction materials, rubble, railway sleepers, and various types of urban waste.
2. Why was Salbertrand chosen and what specifically will be done in this area?
In accordance with CIPE (Interministerial Economic Planning Committee) regulations requiring workplace safety – especially in light of challenges at the La Maddalena construction site in Chiomonte – the Salbertrand site was selected following an evaluation based on several criteria, including its distance from residential areas and its proximity to motorway and railway connections. In 2018, CIPE approved the use of this area as a materials processing site as part of the revised plan for the Italian section of the cross-border Lyon–Turin railway line.
Here, a factory for producing tunnel lining segments will be built, along with storage facilities for raw materials and segments, a reclamation plant, and a connection with the existing railway for the transport of surplus materials. These materials will be reused for the re-naturalisation of the Torrazza Piemonte and Caprie sites. All activities will take place in enclosed facilities equipped with systems to prevent the dispersion of dust. Once operations are completed, the site will be re-naturalised and returned to the local community.
3. Why is Susa being used in addition to Salbertrand?
The Lyon–Turin single construction site spans two relatively narrow valleys, where it is difficult to find large flat areas to carry out excavation, storage, and processing of extracted rock simultaneously. As a result, construction site installations have been planned in both the Susa and Maurienne valleys, turning this physical constraint into an opportunity to increase site efficiency and reduce the consumption of virgin land.
In Italy, since the 2018 Variant Project (which shifted the base tunnel excavation from Susa to Chiomonte), Susa is no longer designated to host the tunnel segment factory and related infrastructure. However, it continues to serve as a temporary storage site for materials.
TELT has created a coordinated system across three key sites: Chiomonte, where the excavation is under way using two TBMs; Salbertrand, where all the main activities of material management and processing remain, in application of the land use plan approved by the Authorities; and Susa, where the temporary deposit of aggregates is planned. At Susa, enclosed sheds will be set up and equipped with systems to control dust and noise, including washing stations for departing heavy vehicles and dust suppression systems inside the buildings. The use of the Susa site for temporary storage and Salbertrand for the processing and recycling is not an alternative but a joint project and has been approved through the necessary regulatory procedures. The areas in Susa currently used for storage are the same that will later house the international station, technical area, and related facilities.
4. What are the next operational steps for the Salbertrand and Susa sites?
The sites are currently being prepared, with initial activities beginning in the first quarter of 2025. They will become fully operational in conjunction with the start of the base tunnel excavation, planned for 2026. In the meantime, the UXT group of companies working at Chiomonte is conducting environmental characterisation surveys on the area where the tunnel boring machine (which has already been ordered and is set to arrive on-site in 2026) will start to excavate. In preparation, the group of companies will construct retaining walls, lower the level of the platform at the tunnel entrance, and begin excavation using traditional methods before the TBM is deployed.
5. Which activities will take place in Salbertrand and which in Susa?
In Salbertrand, sheds will be constructed to store materials arriving from Chiomonte, along with facilities for processing rubble and producing the tunnel lining segments. All operations will take place indoors to minimise environmental impact. In addition, non-reusable materials will be used for the re-naturalisation and environmental restoration of the disused quarries at Torrazza Piemonte and Caprie.
In Susa, by contrast, part of the pre-processed material from Salbertrand will be temporarily stored in the area of the former car-and-truck terminal and the Guida Sicura test track
6. How will the transport between the different sites be arranged?
The project provides for short-distance transport by covered trucks and medium- to long-distance transport by dedicated freight trains. Covered lorries will travel exclusively on motorways – thanks to a new junction being built in Chiomonte – in order to avoid any impact on local roads. Aggregates leaving Salbertrand for Torrazza Piemonte and Caprie will be transported along the existing railway line, then moved via conveyor belts to the two former quarries. .
7. How much excavated material will they process?
Approximately 37 million tonnes of material will be excavated during the construction of the base tunnel: 30 million tonnes on the French side and about 7 million tonnes on the Italian side. The project aims to reuse up to 60% of the excavated rock, while the remaining material will be employed in re-naturalisation and environmental restoration projects at disused sites in both the Maurienne and the Susa Valley. All excavated material is first checked and classified at the point of extraction. Geomechanical tests are then conducted to assess the material’s composition and determine how it can be reused.
8. Will there be dust posing a health risk to the public?
Dust containment will be ensured throughout the temporary storage and handling of excavated material. The storage sheds will be enclosed, and materials will be moved using covered conveyor belts. In addition, at Salbertrand, all processing activities will take place indoors to reduce emissions further. Across all construction sites, strict environmental monitoring is carried out, with parameters tailored to each site’s activities. These controls are defined in agreement with ARPA Piemonte regarding their type and frequency. Results are regularly submitted to central authorities for verification and are also published in environmental bulletins available on the TELT website.
9. What will happen to the areas used for storage once the work is completed?
When the construction work is finished, the processing plant in Salbertrand will be dismantled. The area will undergo ecological restoration and be returned to the community as a public park, with significantly improved environmental value compared to its condition before the works began. Similarly, in Susa, areas not affected by the new railway infrastructure will be re-naturalised and partly repurposed as an agri-park.
10. What does ‘Phase 2 executive project’ mean?
The cross-border section of the project was authorised by CIPE on the basis of the final project (PD/PRV). At present, for each operational site, the involved companies must develop detailed executive projects that define construction methods and choices in accordance with the approved final plan. The so-called “Phase 2” is therefore not a new project, but rather a more detailed implementation phase of the existing one.
This phased approach allows for a focus on the actual construction needs and enables progress in step with newly acquired technical and environmental data. The Phase 2 executive project includes specific operational solutions and detailed planning, such as the management of temporary storage of spoils in the Susa Plain. In the coming months, the document will be submitted to the Ministry of Transport and the Ministry of the Environment for evaluation. These authorities will verify that the proposals align with the already approved final project.
Local mobility during the construction phase
Within this context, the local transport system is being restructured to ensure continued road and rail connections to and from Susa. For rail transport, the priority is maintaining the connection between Susa and Bussoleno, which will temporarily be replaced by a bus service. TELT is coordinating with RFI and local institutions, including schools, to minimise the disruption, aiming to limit the replacement bus service to just one school year. The service will be tailored to the actual needs of students (during school hours) and other commuters from the broader region, from Avigliana to the Upper Valley.
Originally, a so-called ‘diversion’ solution had been studied, which during the works in the Susa Plain, would have allowed trains to continue travelling between Bussoleno and Susa. This involved creating a diversion of over 1 km from the historic line, which would have been built and then dismantled at the end of the Lyon-Turin works. However, in 2023, local authorities opted against this solution to avoid the environmental and logistical impact of an additional construction site in an urban area. For this reason it was agreed to organise a temporary bus service to assure the connection between the two towns. If you have any further questions, please write to us here: TELT Lyon Turin • Contacts
