To complete the Beaver River pipeline crossing in the province of Alberta, contractor Michels Canada ordered a Herrenknecht Direct Pipe system, representing the first use of the technology in Canada. The project involved a pipeline with a diameter of 42 in. (1,067 mm, double FBE coating) to be built over a length of 340 m under the river. The drill was carried out with an entry angle of 4 degrees and an exit angle of 8 degrees with an overburden of around 5 m below the river bed. The target pit was reached after 13 days of drilling between the start on Aug. 24 and breakthrough on Sept. 8, 2013.
Wes Lingerfelt, Direct Pipe operator, was impressed by the performance capacity of the technology: “We reached an impressive 68 m on our best day.”
The crossing beneath the Beaver River is part of a section of the Cold Lake Pipeline extension between La Corey and Hardisty over a total length of 240 km (150 miles). The client, Inter Pipeline Ltd., is expanding its capacities for the transport of the bitumen gained from oil sands in Cold Lake
The Direct Pipe technology developed by Herrenknecht combines the advantages of microtunneling and horizontal directional drilling (HDD) technology. In only one work step, a prefabricated pipeline is installed in the trenchless mode and the required borehole produced simultaneously. This provides for the speedy and cost-efficient installation of pipelines with lengths of up to more than 1,500 m. To date, 35 projects have been completed successfully using Direct Pipe in Germany, Great Britain, Italy, Canada, the Netherlands, Thailand and the United States.
From the launch pit, the soil is excavated using a slurry-supported Herrenknecht microtunneling machine (AVN). The pipeline, which is laid out on the surface on rollers and welded to the end of the microtunneling machine, is pushed into the borehole at the same time as excavation takes place. The necessary thrust force is provided by the Pipe Thruster. It pushes the microtunneling machine forward together with the pipeline with a thrust force of up to 750 tonnes in strokes of 5 m. The force is transferred to the pipeline via the Pipe Thruster clamping unit and then to the machine’s cutterhead.