Many new machines, including vibratrory compactors, have been wheeled in to help build a railbed for the 818km project.
Crossing the hot and remote An Nafud desert, this first phase of the project is known as Phase A and is being constructed by the RTCC- Barclay Mowlem (the Laing O’Rourke Rail Company.)-Mitsui joint venture under a US$765 million contract awarded by (Public Investment Fund) of the Saudi Arabian Ministry of Finance.
The railbed is being laid on an embankment raised on average 3m from the desert floor and 3m wide, using either in situ materials or granite and limestone excavated from borrow pits at various locations in the desert and trucked to the required section of line.
Here, the Dynapac CA280s, supplied new for the project by the manufacturer’s Saudi Arabian distributor and operated by RTCC.
This is the first of four phases of a massive $2 billion initiative to develop a 2,300 kilometer north-south railway system that will link the northern mineral mines of Al Jalamid and Az Zabirah to processing facilities in Ras Azur on the Arabian Gulf.
Rocks
Saudi Arabia is a large producer of ores, including phosphates and bauxite. The mines of Jalamid contain reserves of 313 million tonnes of phosphates, and the Az Zabirah mines contain reserves of 250 million tonnes of bauxite.
Saudi mining company Ma’aden already has a project in place for building an industrial complex to the east of these provinces, so that ore from the region can be transported and refined. The complex will also include an aluminum plant and a large energy generator.
Three locomotives and 150 railway cars will transport the ore, each train 3,000 m in length and weighing an average of 19,400 tonnes, from the mines to the refinery.
The railway will also be extended to serve general freight and passenger services, both northerly and to the south from Hail to Riyadh. The line will be a single track with passing loops. It is the most important land transportation project ever built in Saudi Arabia.
The Public Investment Fund (PIF) of the Ministry of Finance, Kingdom of Saudi Arabia, is the owner and has the role of implementing the NSR.
A multi-national consortium led by the Berger Group, and including Canarail of Canada, Systra of France and Khatib and Alami of Saudi Arabia is carrying out construction supervision.
Riyadh
Construction phases of the NSR each relate to the four major geographic segments of the project and have separate milestones for completion. Phases A and B relate to the lines that will support mineral traffic.
Phase C covers the main passenger and general freight segment of the project between Riyadh and Az Zabirah. Phase D covers the extension to the Jordanian border.
The contract won by the consortium consisting of Barclay Mowlem of Australia, Al Rashid Trading and Construction Company (RTCC) of Saudi Arabia and Mitsui and Co of Japan is for Phase A and is worth US$765 million.
Starting from the Al Jalamid phosphate mines, the line will pass through Al Jawf, Hail, and Az Zabirah. From Az Zabirah it will connect through a direct link to the processing facilities at Ras Azzawr.
This phase crosses 818km of remote desert, with RTCC’s role covering the earthworks and the civil works.
The earthworks include 10.3 million m3 of excavation and 26.95 million m3 of embankment. Nine bridges will be built by RTCC, along with 884 culverts and 22 camel crossings. Work started on April 1 last year.
Sleepers
With the earthworks well advanced, Barclay Mowlem will begin work in December on laying the sleepers.
These are being manufactured by PCM Strescon of India on site. China is supplying the steel for the rails, and the first shipment of 7,500 tonnes arrived in early April.
Progress is anticipated at about 2km a day, with the completion date set for October 2010.
Asaad Arabi, who heads the RTCC side of the consortium, says that there are three types of earthworks required for the railbed.
Granite
He says that the largest part of the works involves the compaction of granular material found in situ and consisting mainly of sand and granite.
A substantial proportion however requires the excavation of granite and limestone from the borrow pits, from where the various materials are brought to the site and are then placed between two embankments made from the sand and granite.
A thin layer of sand and granite is then laid over the top of this, and compacted.
The third method, which is used infrequently, involves importing sand fill into the sand and granite embankments, and then compacting it. This is a long process.
Compactors
Mr Asaad says that the 24 Dynapac vibratory rollers are compacting the fill to a density of 95 percent. The rollers require three or four passes over the sand and granite fill.
“We have 24 compactors out there, working on a very long linear project to a very tight schedule.”
“I am very happy to say that all 24 machines are working well and that our only bit of downtime is that we have scheduled for regular maintenance” he said.