‘Deep renovation’ of Mont Blanc tunnel to go ahead despite ‘very significant’ rockfall

According to media outlets including Italy’s press agency Agenzia Nazionale Stampa Associata (ANSA) Valle d'Aosta Governor Renzo Testolin confirmed on 30 August that plans to close the Mont Blanc tunnel between Italy and France for 15 weeks from early September for maintenance work would go ahead. Work on the tunnel will entail the complete reconstruction of two portions of the tunnel vault measuring 300m each.

The confirmation came despite concerns about the disruption and economic impact of the rock fall and landslide caused by extreme weather over the weekend.

Fréjus Tunnel operator SFTRF stated that the “very significant” rockslide had occurred in the nearby town of Freney on the afternoon of 27 August. The rockfall blocked a road and extended as far as the railway line.

France’s state owned rail network operator SNCF Reseau stated on Twitter (X) that work to repair the tracks near the Fréjus Tunnel damaged by the rockfall could not begin until the mountainside had been stabilised. Rail traffic between Saint-Jean-de-Maurienne and Modane on the French side of the border will remain suspended until further notice.

One of the suggested diversions while the Mont Blanc Tunnel is closed is to take the Fréjus Tunnel. However, thunderstorms in France on 27 August caused the temporary shutdown of the tunnel along with another key route, the Brenner tunnel, although the latter reopened on the evening of 29 August.  On 30 August it was taking over two hours to cross the Mont Blanc tunnel due to traffic jams linked to the problems created by the landslides.

The Fréjus Tunnel, which connects Modane in France to Bardonecchia in Italy, remained open to light vehicles but while authorities worked to reopen it to freight traffic, heavy goods traffic had to be diverted from the Fréjus Tunnel through the Mont Blanc Tunnel, initially casting doubt over the planned repair schedule for the Mont Blanc route.

From 4 September to mid-December 2023, over 60 years after its initial construction, the Mont Blanc Tunnel's scheduled repair work will go ahead. The complete reconstruction of two portions of the tunnel vault measuring 300m each makes it one of the first major European tunnels to undertake deep renovation work on its structure.

The project requires the total closure of the tunnel for a duration of 15 consecutive weeks. With the scheme now set to go ahead, authorities estimate the tunnel will reopen again on 18 December.

Added to northern Italy’s woes, the Gotthard Base Tunnel, a separate alpine rail route through Switzerland, has been shut since 10 August after a freight train derailed inside it.

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