Fracht UK Projects has worked in collaboration with Partners Collett & Sons on the £100 million contract to excavate a 5 km tunnel under the River Humber to carry a replacement gas pipeline. The two had to deliver the tunnel boring machine, named Mary, from Immingham docks to Goxhill and devise a cohesive plan for delivery that would be in line with all shareholders’ requirements.

The tunnel boring machine Mary consisted of four components: 30 Tonne Cutter Head – 4.8m (L) x 4.5m (H) x 4.5m (W), 70 Tonne Shield – 4.5m (L) x 4.4m (H) x 4.5m (W), 95 Tonne Machine Can – 9.6m (L) x 4.4m (H) x 4.5m (W) and 20 Tonne Tail Shield – 3.8m (L) x 4.5m (H) x 4.6m (W).

The 27 mile journey to the Humber Gas Pipeline Project National Grid Site in Goxhill, North Lincolnshire is a route that poses several obstacles, with numerous tight bends and turns. The largest loaded component, the machine can, featured a 29 m rigid length, and utilising these dimensions allowed the Team to mimic the trailer and vehicle’s behaviour at select parts of the route to identify any amendments to the surrounding topography or manual steering requirements to ensure safe passage.

Three and a half hours after departing from the Port of Immingham the first two loads, the cutter head and the shield, completed the 27 mile journey under Humberside Police and private escort arriving safely on site by mid-afternoon.

Over three days all four cargoes were unloaded from the vessel and safely transported to the Humber Gas Pipeline Project National Grid Site in Goxhill. Once assembled, the tunnel boring machine Mary will be used to build a replacement high pressure gas pipeline from Goxhill to Paull, housed within a tunnel underneath the River Humber. The pipeline will replace the existing one which lies on the riverbed and is due for completion in 2019. After it gets built it will become the longest gas pipeline in a tunnel inserted in a single string in the world.