Boskalis is working in the south of Oman. The challenge there can compare in terms of size and complexity with major projects such as Maasvlakte 2 and Gorgon. This Duqm Liquid Bulk Berth Project is breaking records in terms of both productivity and safety.
The project involves the creation of an enormous port area that will house, among other things, a bulk terminal and a refinery. Boskalis is executing this engineering, procurement & construct contract for the Special Economic Zone Authority Duqm. “What makes this project unique is that we first drained a large part of the future port by constructing a temporary ring dike, pump and keep out all water and then building all the structures in this so-called polder,” Project Director Bart Pröpper said. Operations began in 2017 with an intensive design and preparation phase, and extensive soil surveys. The work included the construction of a large port basin and an entrance channel with a depth of 18 meters, and the construction of a kilometer-long quay wall and two 400-meter-long jetties. Boskalis started the second phase of the major land reclamation for the port area in the first half of 2019. The perimeter of the area will be protected with geotextile and a total of 1 million tons of rock.
Sand supplies and compaction
During the first phase of the project, the trailing suction hopper dredgers Queen of the Netherlands and Prins der Nederlanden pumped in millions of cubic meters of sand for the land reclamation and the construction of the temporary ring dike. For phase two the hopper Fairway will pump in a similar quantity of sand as in phase one. The excavation and large-scale earthmoving work for the construction and deepening of the polder, with a total volume of 9 million cubic meters, was carried out under the supervision of colleagues from Boskalis Nederland involving over 80 units of dry earthmoving equipment. Our subsidiary Cofra is compacting the reclaimed area. Some of that work has now been completed and the areas in question have been tested and handed over to the client.
Quay wall and jetties
Working with our partner Six Construct, Boskalis built a gigantic quay wall on the edge of the extensive polder. More than 5,000 large concrete blocks were required for this operation and they were produced elsewhere on site. At the same time, the impressive steel structures were built in the middle of the polder for the two jetties. That involved installing 330 large steel piles that were then connected to each other with steel beams and in situ poured concrete platforms.
New type of cutter head
In late 2017 the cutter suction dredger Helios started the first phase of dredging for the entrance channel to the new port area. It also started excavating the outer section of the port basin. “We came across a lot of tough rock in this first stage. It was a challenge for the dredger,” Pröpper said. “To get the job done, a team of Boskalis specialists developed and produced new cutter heads within an extremely tight schedule. Since October 2018 the Helios has been using them to remove the remaining 15 million cubic meters of various types of rock.”
Flooding the polder
After the completion of the civil engineering work, the polder was flooded in mid-January 2019 using large siphons and so the impressive engineered structures are now largely hidden from view. “From a technical and logistical point of view, we have achieved something very special here,” Pröpper concluded. The final completion date for the project is April 2020.