1M tonnes of waste reused as dredger arrives to complete tunnel’s river works

Following immersion, at the end of February, of the final tunnel element to make up the river section of the second Tyne vehicle tunnel, the dredger “Alexander von Humboldt” arrives on the Tyne today (Tuesday) to start backfilling the trench.

The huge 120m long, 24m wide trailing suction hopper dredger will remove clean material from the mouth of the Tyne and place it via pipeline into the tunnel trench between East Howdon and Jarrow helping to ensure the tunnel beneath the riverbed remains securely in place.

Backfilling is expected to take up to seven days to complete. The dredger will also be used to infill the Howdon Basin on the north bank of the Tyne and to reinstate the riverbeds either side of the river. The source of the materials used for the backfilling operations is the routine maintenance dredges of the Tyne, carried out by the Port of Tyne and normally disposed of at sea.

Trevor Jackson, Managing Director of TT2, and New Tyne Crossing’s Concessionaire, said: “The work this dredger will do represents another proud achievement for the New Tyne Crossing project. By reusing the clean, inert material from the river’s maintenance dredges we are saving about 170,000m3 of material from being disposed of at sea. This is in addition to the 400,000m3 of material that was due for disposal at sea and landfill following the excavation of the river channel last year, all of which was reused to infill Tyne Dock. This represents around one million tonnes of reused waste in total, which I consider to be a fantastic environmental saving.”

Nicolas Caille, Project Managing Director of Bouygues Travaux Publics, the design and build contractor for the project, said: “This is possibly one of the largest dredgers to work this far up the Tyne. It has a vital job to do when it gets here, helping to refill the river bed where the tunnel has been placed. Once the dredger has finished its work, the rock armour will be put into place above the tunnel to protect it, leaving us to concentrate on completing works on the inside of the tunnel.”

Paul Fenwick, Project Director for the Tyne and Wear Integrated Transport Authority, the project promoter, said: “We reached a fantastic milestone last week, as the closure joint that links the final tunnel elements together was opened up. With backfilling of the trench above the tunnel due to start, it shows that we’re moving into the final phase of work for the river section of the new tunnel.”