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Dredging, reclamation and dewatering works, Gas-to-Liquids facility Escravos

The Escravos Gas-to-Liquids facility (EGTL) converts natural gas feed into high quality, environmentally superior, liquid GTL fuel, naphtha, and LPG products. The facility feed is approximately 320 million SCFD of natural gas and the facility produces approximately 33,000 BPD of products. The EGTL facility will be built on the north bank of the Escravos River tidal outlet, in the Niger Delta about 2 kilometers north of its confluence with the Atlantic Ocean on the Bight of Benin, approximately 100 nautical miles south east of Lagos, and 37 nautical miles west of Warri, Nigeria.

The EGTL facilities was built adjacent to the existing Escravos Terminal and Gas Plant. The building site consisted of a greenfield site, with the existing environment consisting of mangrove and freshwater elements, typical of brackish water sources dominated by the sea, and geotechnically very poor soil conditions. Chevron Nigeria Limited selected a piled raft foundation for its plant structures, and this was used as the basis for defining the Dredging, Reclamation and Dewatering Works. The work consisted of dredging 3,000,000 m3, hydraulic sandfill of 70 ha (max. 8 m thick), the installation of closely spaced prefabricated drains, the lowering of the water table over an area of approximately 30 ha by active pumping and the installation of the necessary monitoring instrumentation.

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Dredging of sediments, Miami river

The Miami River, which flows through an urban industrial area of Miami, Florida, had not been dredged since the area was built in 1934. In 1990 the US Army Corps of Engineers advised the city that the sediment had to be removed from the river as it was impeding shipping. There was one caveat however: the sediment, contaminated with heavy metals, pesticides and oil, could not be placed in the ocean.

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Gas fields development, Krishna Godavari basin

A large-scale dredging, trenching, pipe pulling and backfilling project. Reliance Industries develops the offshore gas field known as Block KGDWN-98/3 in the Krishna Godavari Basin, Bay of Bengal off the East Coast of India. The gas field will be linked to onshore customers and covers an area of approximately 7,500 km2. The field stretches an area 40 to 60 kilometers southeast of Kakinada. The scope of works comprised the dredging of a 21 kilometers long and 18 meters wide trench for three 24" gas pipelines, each with a 6" piggyback pipeline, one 12" effluent pipeline and two umbilical cables in water depths ranging from 0 to 50 meters. After pipe laying by the main contractor the pipeline trench was backfilled with partly rock and sand.

Rehabilitation of old breakwater, Port of Poti

The city of Poti is located at the mouth of Georgia’s largest river, the Rioni. It has been an important trade centre for centuries. Since the early 19th century, many plans have been developed for the creation of a major sea port. Construction work started in the 1850s on the main breakwater that is still protecting the port today. During its long lifetime, this structure has been maintained by frequently adding 20-60 tons of concrete cubes to the armour layer. Significant settlement of the structure over time has lowered the crest level considerably, resulting in large overtopping volumes and therefore in port-operation downtime. As a result, a rehabilitation project was executed between 2006 and 2008 by Royal Boskalis Westminster N.V. to reduce the downtime caused by overtopping waves.

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Reclamation and dewatering works, Sepetiba Bay

The German steel-maker ThyssenKrupp Steel and the Brazilian mining giant Companhia Vale do Rio Doce (CVRD) teamed up to construct a EUR 3 billion steel factory at Sepetiba. This is a small town of 36,000 inhabitants near Rio de Janeiro with good access to the Atlantic Ocean. The new steel factory allowed Brazil not only to export more of its plentiful mineral resources, but also to produce semi-finished products that can be sold at higher margins. The government authorities of Brazil and Rio de Janeiro both supported the project.

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Port development, Lerwick

The Port of Lerwick is situated on the east coast of the Shetland Islands, and is operated by Lerwick Port Authority. The 2008 dredging and reclamation works were one of the largest marine projects to be carried out in Scotland in recent years and constituted the largest single investment in the port to date.

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Port construction, Vuosaari

Vuosaari Harbor is the most significant harbor project in Finnish history; in fact, it is unique even on a European scale. Both existing harbors in Helsinki’s city centre are being transferred to the eastern outskirts of the city. They are being replaced with a harbor with excellent traffic connections that can meet the increasing demand for cargo handling. The Vuosaari Harbor Center will provide a competitive and modern service package, with smooth connections between harbor operations and other logistical facilities. The harbor center will comprise the gate area, the closed harbor area and the adjacent Business Parks. The fairway to the Harbor Center will be 32 km long, at least 200 m wide, and 11 m deep. The port area comprises 150 ha, of which 90 ha will be land reclaimed from the sea.