 The slight slope towards the Italian side favoured a frequent infill with debris carried by the thaw, but this was remedied by the recent installation of an anti-avalanche structure at the French entrance.The technical difficulties of the work were remarkable.It is necessary to consider that at an altitude of 2,882 metres the snow cover is present for about eight months a year, therefore the working times were necessarily concentrated in the summer, but then violent meteorological events may occur.