Dragados-Sisk Limmo Shaft (TBM Grout Plant)



Dragados-Sisk Joint Venture
Crossrail Project – Contract C305
London, England

30 m3/hr



  • Conceptual Design
  • Mechanical Engineering
  • Fabrication of all Equipment
  • Commissioning
  • On-Site Training and Site Support


  • Tornado 1600 Colloidal Mixer
  • 40’ Heated Container
  • 4000 litre Agitation Tank
  • Three 143 m3 Capacity Binder Silos
  • One 100 m3 Capacity Bentonite Silo
  • Four Screw Conveyors
  • Two 82.5 m3 Heated Accelerator Tanks
  • Automated PLC/MCC Control System
  • Air Compressor & Pneumatic System
  • Admix System
  • Water Weigh Hopper
  • Grout Piston Pumps & Powerpacks

Dragados-Sisk JV was awarded the Crossrail C305 contract which entails three separate twin tunnel drives including the project’s longest drive, the 8.3 km push (Drive Y) from the Limmo Peninsula through Canary Wharf, Stepney Green, Whitechapel, Liverpool Street and finally arriving at Farringdon. The Project’s shortest drive (Drive G) will also launch from the Limmo Peninsula shaft and includes parallel 930 m tunnels to the Victoria Dock portal. Three Herrenknecht 7.08 m diameter EPBM machines will be used.

Team Mixing Technologies Inc. designed and constructed a single bi-component (A/B type) grout plant to feed the three TBM’s. Hydrated bentonite is used to prepare the “A” component grout in order to minimize bleed. This is particularly important over the long 8.3 km runs where high pressure piston pumps are used to pump the grout to the TBM holding tanks. A large capacity colloidal mixer is employed along with a water/hydrated bentonite weigh hopper to reduce batch cycle times and meet the required 30 m3/hr capacity.

Team Mixing also provided a pair of sodium silicate (accelerator) holding tanks, fully insulated and heated. Accelerator is taken to the TBM via rail cars.