Dredging, Reclamation & Storage of TBT Contaminated Silts at Musgrave Channel

Dredging, Reclamation & Storage of TBT Contaminated Silts at Musgrave Channel

Contract Value: £3.1m
Consulting Engineer: Doran Consulting
Engineer's Representative: Campbell Davis
Client: Belfast Harbour Commissioners
Client's Representative: Eugene McBride
Works Completion Date: January 2017

Scope of the Works:

Ashleigh Contracts were appointed as main contractors working for Belfast Harbour Commissioners at Musgrave Channel.

The works commenced on site in March 2016 and were completed in January 2017 and comprised:-

-          The construction of a 180m long Containment Bund formed from 70,000T of Core Material and 28,000T of primary and Secondary Rock Armour. The inner face of the Bund was also protected with a heavy geotextile membrane to allow for the infilling and containment of dredged silts.

-          Dredging and reclamation into the Containment Area of approx. 50,000m3 of TBT Contaminated silts.

Ashleigh undertook the works using their own in-house range of specialist plant and equipment including Long Reach Excavators under 3D GPS guidance and their own spudleg Barge and associated attendant workboats. In addition to the Prolec GPS machine control system, a Sonar 3D underwater scanner was utilised for surveys of the seabed levels and adjacent marine structures. An 800m3 capacity Hopper Barges was used for transferring the dredges silt to a quayside offloading facility – from which the silt was transported primarily by 40T Dumptrucks with sealed tailgates. The silt was deposited within the Containment Area with level control maintained by long reach excavators operating both from the shore and from floating pontoon barges.

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