One million tonnes of excavated tunnel material has been removed from Tideway’s Kirtling Street site by barge.

Two tunnel boring machines (TBMs), Millicent and Ursula, are currently working deep below the River Thames driving west and eastbound respectively. Millicent, launched late last year, has completed 4.3km of her 5km journey towards Carnwath Road in Fulham, while Ursula has completed 2.3km of her 7.5km eastbound drive to Bermondsey, having set off earlier this year.

The 8.8m diameter cutterheads at the front of the machines dig and extract the spoil. That then travels along a conveyor system to the bottom of the shaft at Kirtling Street before it is transported to ground level using a high angle conveyor. Once at ground level, it is transferred into the site’s muck bay holding area or, if available, directly onto a waiting barge.

A total of 710 barges have removed the material from Kirtling Street to date, and each barge can hold up to 1,600 tonnes of spoil, with up to five barges attending site per day. Utilising the river to transport the spoil has removed the need for over 50,000 lorry movements on the roads in the local area.

Darren White, Head of Sustainability at Tideway said "This milestone is a testament to the hard work and commitment of our supply chain partners and stakeholders to deliver a more sustainable mass haul of materials. Not only is the use of river resulting in less congestion and air pollution for the communities that we work in and reducing the risk to other road users, but the material coming our tunnels is being beneficially used to restore landfill sites, such as Rainham, into Nature Reserves that will help encourage biodiversity for future generations."

Most of the spoil from Millicent and Ursula's drives is sent to Ingrebourne Valley’s Tilbury Ash Disposal site and Rainham for beneficial reuse.