The assembly of Tideway’s two largest Tunnel Boring Machines has reached a key milestone with their most important components now attached, as the start of tunnelling on London’s new super sewer edges closer.

The two TBMs, Millicent and Ursula, will be used to dig the central section of the Thames Tideway Tunnel, a 25km super sewer tunnel being constructed to tackle the problem of sewage pollution in the River Thames.

The machines have had their cutter heads attached, a radial assortment of metal teeth on the front of the machine which rotate allowing them to grind through the ground to create the tunnel.

At 9 metres in diameter – almost the length of a London bus – and weighing in at 110 tonnes each, the cutter heads are the largest pieces of the machines.

Chris Darton, Delivery Manager at Tideway, says, “It is exciting to have the cutterheads now attached, bringing the assembly of the TBMs nearer to completion. We’re now focused on getting them finished and gearing up for the start of tunnelling later in the year.”

Millicent will tunnel 5 kilometres from Kirtling Street to Carnwath Road in Fulham while Ursula will tunnel 7.6km from Kirtling Street to Chambers Wharf in Bermondsey.

The extracted spoil that the cutterhead creates is taken up by an excavator screw at the front of the machine and drops onto a huge conveyor belt system trailing behind it. It’s then brought to the surface for removal by barge.

Tideway has made a commitment to transport over 90 per cent of materials by river which will reduce the number of road vehicle journeys needed to build the tunnel.

The Kirtling Street work site is being constructed by the Ferrovial Agroman UK and Laing O’Rourke joint venture which is delivering the central section of the project. For further information please visit https://www.tideway.london/news/media-centre/assembly-of-millicent-and-ursula-nearing-completion/