Terasen Gas is the largest natural gas distribution utility in British Columbia, serving ~840,000 customers on the mainland. Terasen’s South Fraser River crossing upgrade project involved the construction of twin 1.4 km long, 508 mm (20”) and 610 mm (24”) pipes underneath the South Arm of the Fraser River using horizontal directional drilling (HDD) technology. The project was subject to review by several regulatory bodies including Fisheries and Oceans Canada, BC Oil and Gas Commission, Port Metro Vancouver, Transport Canada, the Agricultural Land Commission and the British Columbia Utilities Commission.
Dillon undertook the environmental assessment of aquatic and terrestrial habitats and coordinated project approvals for the HDD replacement of the two transmission pipelines. In addition, Dillon’s impact mitigation plan addressed potential environmental, agricultural and archaeological impacts of project construction and described methods to mitigate potential effects.
HDD allows operators to drill and set pipe for a kilometre or more horizontally through rock formations. The technology employed is so advanced and exacting that drillers today can hit a target at the end of a drill string that is 3 000 m vertical with a kilometre long horizontal section that is no more than a few inches in diameter. This proved beneficial in drilling this twin main underneath the South Arm of the Fraser River.