Seattle Tunnel Partners (TBM Grout Plant)



Seattle Tunnel Partners
SR99 Viaduct Replacement Tunnel Project
Seattle, WA

30 m3/hr



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


  • 40’ Heated Container
  • Tornado 1600 Colloidal Mixer
  • 4000 litre Agitation Tank
  • Three 108 m3 Capacity Silos
  • Three Screw Conveyors
  • Automated PLC/MCC Control System
  • Pneumatic System
  • Admix System
  • Water Weigh Hopper
  • 100 mm Grout Peristaltic Pump
  • Two 50 m3 Heated Accelerator Tanks
  • 50 mm Accelerator Peristaltic Pump

In July 2013 the world’s largest diameter tunneling machine began a historic journey beneath downtown Seattle. Its purpose: dig a tunnel to replace the State Route SR 99 Alaskan Way Viaduct, a double-deck highway that has spanned the downtown waterfront for more than half a century but was damaged in a 2001 earthquake.

The project includes a 1.7 mile long tunnel beneath downtown Seattle, a mile-long stretch of new highway that connects to the south entrance of the tunnel, near Seattle’s stadiums and a new overpass at the south end of downtown that allows traffic to bypass train blockages near Seattle’s busiest port terminal.

Team Mixing Technologies Inc. provided a 30 m3/hr capacity bi-component (A/B type) grout plant, with colloidal mixer, to feed the giant 17.6m (58 ft) diameter Hitachi-Zosen manufactured TBM. Also provided were insulated and heated 50 m3 capacity sodium silicate storage tanks along with a peristaltic pump to transfer the accelerator to the TBM.