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20,000 concrete blocks and 7 million tonnes of rock

Maasvlakte 2 will be protected from the sea in two ways. To the southwest, the land reclamation will be protected by a beach with dunes. In the north, the contractors will construct a 3.5-km hard seawall. This will consist of various layers of rock and concrete.

Concrete

20,000 concrete blocks, measuring 2.5 by 2.5 metres and weighing 40 tonnes a piece, will be taken from the block dam that protected the existing Maasvlakte from the sea. The blocks, which weigh over 40 tonnes, will be picked up by a backhoe that has been fitted with a ripper grab. After this, the blocks are transported overland with low loaders to the hard seawall of Maasvlakte 2. A crane designed especially for this job, the Blockbuster, will then position them in the dam.

Most of the concrete blocks will lie below the waterline, on a base of different layers of rock. The block dam is situated in front of the stony dune and will serve as a breakwater. As a result, the sea will have less of an impact on the structure.

Rock

A total of some 7 million tonnes of quarrystone will be required to make the hard seawall sufficiently robust. Approximately 2 million tonnes of rock will be recycled and, like the concrete blocks, will come from the existing Maasvlakte seawall.

The remaining 5 million tonnes of rock will come from a quarry in the Norwegian district of Bremanger, some 200 kilometres to the north of the city of Bergen. This quarry supplies an extremely high quality product. The rock is of good quality and has a homogeneous composition. It is both rough and hard – a unique combination for rock. The product’s roughness is important because it ensures that it will stay in place in the seawall. Its hardness ensures that it is hard-wearing and as a result sustainable. Since January 2010, a bulk carrier has been unloading 90,000 tonnes of rock at the PUMA construction site in Yangtzehaven every two weeks. Once it has unloaded its cargo, the bulk carrier returns to Norway to pick up the next load of rock. The crossing takes two days.

This cycle will be sustained for two years, until the entire seawall is firmly in place. In the meantime, the delivered loads are made suitable for incorporation in the hard seawall. To this end, the rock is transported via a conveyor belt from the special docking area to the shore. Here, the rock is distributed by a swivelling transporter belt. This unloading process alone takes 36 hours. Dumpers, i.e. 'tipper trucks' transport the quarrystone to a sifting installation. After two weeks, the whole process starts all over again.