Crossrail has taken another step towards the creation of a new 1,500 acre RSPB nature reserve with the completion of a new 180 metre jetty at Wallasea Island in Essex.
The jetty will receive in the order of 4.5 million tonnes of material excavated during Crossrail’s tunnelling operations in London.
The jetty, constructed by BAM Nuttall, comprises two 800 tonne steel pontoons, each 15 metres wide, and is able to accommodate two 90 metre, 2,500 tonne ships simultaneously. At peak, two unloading machines per pontoon will service four ships and unload up to 10,000 tonnes of material over a 24 hour period.
An 800 metre conveyor system to transport the material within the site has also been completed. The conveyor stretches from the jetty to a holding point for the excavated material, from which the material will be distributed around the site by truck.
Excavated material will be unloaded directly from the ship on to the conveyor system. To accommodate tidal movements of up to six metres, the conveyor comprises a flexible section on the pontoon connecting to a fixed shore section.
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Dredging Today Staff, August 6, 2012; Image: crossrail