 Approximately 315 meters of the tunnel's length features a continuous grouted ceiling, which was done to reduce deformation and permeability as well as a potential loss of cover.This was created by injecting a precise mixture of cement and slurry via pressurised grouting pipes across 120,000 valves; areas were tested for potential weaknesses and promptly re-grouted where appropriate.From an early stage of the project, the tunnel's opening was projected for June 2003, a date which was fulfilled on time.