The Mole Silt Strengthening


Milford Haven Port Authority


Milford Haven Docks

A Grade 2 listed structure built during WW2 had become undermined due to tidal and wave action. Strengthening and consolidation of the founding material was required to allow underpinning and stabilisation works to proceed.

Works involved:

  • Construction of a temporary stone working platform to increase intertidal working window.
  • Drilling and injection at high pressure a thixotropic high strength grout to consolidate the soft marine silts.
  • Removal of debris and soft silts from the scour by airlifting and water flushing.
  • Construction of shutters and flood scour with concrete to create a foundation.
  • Injection of grout through the new foundation to consolidate the base of the structure.
  • Re-building damaged concrete bagwork facing on new foundation. 

All works were carried out in line with conditions set out by the Marine Licensing Authority. The works involved liaison with Natural Resources Wales in order to obtain marine licences, and works to the Mole required Listed Building Consent to be obtained. We developed methods of working which met all conditions specified in the Marine Consent.