London’s Crossrail project has signed an agreement to lease land at Lafarge’s former cement works at Northfleet as a temporary logistics facility. The site will receive all the excavated material from Crossrail’s western tunnels that run from Royal Oak to Farringdon. The site will receive excavated material by rail and briefly store it before loading it onto ships for delivery to regeneration sites for reuse.
Rob Holden, Crossrail Chief Executive said, “The Northfleet site will enable Crossrail to move over 90% of the excavated material coming out of Royal Oak Portal from the western tunnels and stations by rail and water due to its strategic location on the banks of the Thames Estuary and dedicated links to the rail network. This will greatly assist in reducing the level of Crossrail lorry movements in central London.”
A total of 21km of twin-bore tunnel is required to be constructed for Crossrail. Construction of the first six tunnel TBMs is underway at Herrenknecht in Germany. The first TBM is due to arrive in London in early 2012 with tunnelling commencing in spring 2012.
During the delivery of Crossrail, a total of over 6Mm³ of material will be excavated. Close to 100% of the excavated material is expected to be clean and uncontaminated and reusable elsewhere.
It is critically important that Crossrail’s impact on central London is kept to a minimum. Crossrail changed the tunnelling strategy on the western tunnelled section to build tunnels first and then excavate the stations. This significant change enables excavated material to travel through the new tunnels and emerge at the Royal Oak Portal rather than be transported by lorries through the busy streets of London.
Northfleet has been chosen because it is located on the River Thames with deep-water wharfage and links to the National Rail network, offering Crossrail the ability to transport excavated material from the new tunnels by rail and then transfer onto barge. Reinstatement of the freight rail link into the Northfleet site from the North Kent Line is now underway. The length of the rail link is around 2.25km and in total 4.75km of new track will be provided.
Kent County Council has recently granted planning approval for the Northfleet site to be used as a temporary excavated material logistics facility. The site also has planning permission to serve as a concrete tunnel segment manufacturing facility should the need arise.
Excavated material from the eastern tunnels (running from Limmo Peninsula to Farringdon and Stepney Green to Pudding Mill Lane) will emerge from the Limmo shaft and be brought by conveyor to Instone Wharf for loading onto barges bound for Kent. Excavated material from the Pudding Mill Lane Portal will be brought to Northfleet.
For the Thames Tunnel which will be constructed between Plumstead and North Woolwich, the excavated slurry material will emerge at the Plumstead Portal, where it will be filter pressed to reduce its water content before transportation for reuse.