Construction on Coastal GasLink
Coastal GasLink will be built using the safest, least disruptive construction methods that have been developed over the past three-quarters of a century. Each section (also known as a spread) can take several weeks to construct, depending on terrain, before crews move on to the next section.
Eight stages of pipeline construction
1. Clearing and grading
After crews identify and mark the pipeline right-of-way, the topsoil is removed and stored for future reclamation. The ground is then prepared to ensure the surface is level for construction equipment.
Construction crews use backhoes or ditching machines to dig a trench for the pipeline.
Pipeline crews line-up sections of the pipe end-to-end along the edge of the trench. A machine bends the pipe to ensure it follows the route and contour of the land.
Welders join the pipe segments together. Each weld is inspected and certified using X-ray or ultrasonic technology. Pipeline joints are coated with an anti-corrosion material and then the coating is inspected.
Following careful inspection, a special crane lowers the section of welded pipe into the trench. A separate crew completes the final welds (tie-ins) connecting continuous lengths of pipeline.
The soil is returned to the trench and is replaced in the sequence it was removed to bury the pipeline. The land is prepared for reclamation.
7. Pressure testing
The pipeline is filled with water and pressurized to a level that exceeds the operating pressure of the pipeline, ensuring it’s ready to transition safely to operation.
Once testing is complete, the right-of-way is stabilized and the ground surface is contoured to reestablish original drainage patterns. The topsoil is replaced, allowing for the re-establishment of appropriate vegetation. The goal is to bring the land as close to the original state as possible.
We go to great lengths to help keep waterways safe, using the following methods:
- Trenchless: This method does not involve in-stream work. Horizontal directional drilling is a common trenchless method, as noted in the diagram.
- Isolated crossing: This method temporarily redirects the stream while the pipeline is laid into place. The dam is removed and the stream returns to its normal course.
- Open cut: This method is generally used when the watercourse is dry, frozen or has limited fisheries values, or as a contingency crossing method for large river crossings.
Property tax revenues from Coastal GasLink can help build things like schools, roads and hospitals.