One such pipeline is owned by Petroleum Development Oman, a joint venture between the Omani government and several oil companies. It originates close to the Saih Nihayda Gas Plant and will terminate at an existing Block Valve Station located close to the Al-Kamil Power Station. The general contractor on this project is a joint venture between Punj Lloyd and Al Hassan, and V2 Trenching was chosen as the subcontractor to dig the trench.
“The project owners had seen our work and operations in Qatar and thought that we offered a viable alternative to traditional construction methods,” said Tom King, Project Manager for V2 Trenching in Oman. “We already had an operation in the region, and an inspection of the pipeline route suggested that the trench could be cut efficiently using powerful chain trenchers.”
V2 is using four Trencor trenchers – an 1860HD, a 1660HDE, a 1660HDE Magnum, and a 930HD wheel trencher – to complete this project. “Trencor’s mechanical trencher drive technology is unparalleled in cutting hard rock,” said Mr King. “We don’t own trenchers from any other manufacturer.”
According to Mr King, there are many benefits to using chain trenchers on projects of this type. “Our chief advantages are the speed and compactness of our operation. We have a total of eleven men on this pipeline project, including myself. We can be much more economical with fewer men to house and feed and less machinery and fuel to move about and control than traditional excavation or drill/blast techniques.
“Plus, with a trencher, the excavated material is already processed and ready to use as backfill once the product pipe is put in place. When you compare that to the possibility of having to use up to fifty excavators, drilling/blasting crews, and processing the excavated material, the savings are phenomenal.”
V2 Trenching began cutting trenches for the pipeline in July 2004. Initially, the trench width specified was 1.55 m, but after an initial review, the trench was widened to 1.83 m to allow smoother installation of the 48 inch diameter product pipe.
To date, V2 has completed 110 km of the total 264 km length, with depths varying from 2.35 m to 2.85 m, depending on local conditions. On occasion, they have dug as deep as 3.35 m. “We are in the hardest section of the job at the moment, and we are averaging approximately 145 to 150 m of trench dug per hour of operation, using only the 1860 and the 1660 Magnum trenchers,” said Mr King. Given the fact that they’re working in rock with compressive strengths that average between 8,000 and 10,000 psi, their production rates are even more impressive.