We are pleased to announce that in the 2020 edition of the Great Lakes, St. Lawrence & Atlantic Trenchless Journal, CCI’s Sam Wilson and Jeff Miller along with Adam Van Nood from Marathon Underground had their paper “Shore Approach Horizontal Directional Drill Crossings into the Bay of Fundy, New Brunswick” published. Way to go guys!
Shore Approach Horizontal Directional Drill Crossings into the Bay of Fundy, New Brunswuick
New Brunswick Power Transmission Corporation (NB Power) is constructing the Fundy Isles Transmission Power Line Project which consists of 69 kV Submarine Cables from Deer Island, NB to Campobello Island, NB and from Campobello Island to Grand Manan Island, NB. This project will provide electricity to the islands and will replace existing cables installed in 1978 and nearing the end of their service life.
NB Power requested that the connection between the submarine and the land-based sections of the project be completed utilizing the Horizontal Directional Drill (HOD) methodology to mitigate any concerns of future exposure due to erosion from the large tidal action within the bay. The HOD crossings were to include the installation of three HOPE conduits, one 16-inch 0.0. HOPE conduit along with two spare 3.5-inch HOPE conduits for future corrosion protection measures inside a 24″ common borehole. The project included four shore approach crossings, designed to be progressed through 0-50% ROD Mafic Tuft, Shale bedrock, and overburden materials.
Marathon Underground (Marathon) was successful in the tendering process for the project. CCI Inc. (CCI) was subcontracted to assist with production of feasible designs and provide HOD construction experience and support.
The unique nature of the shore approach methodologies, space constraints, marine activities, and difficult ground conditions at the crossing locations culminated in complicated conditions for HOD installations.
Through comprehensive engineering design, significant combined HOD experience, and Marathon’s ability to adapt to onsite conditions, two of the four crossings were successfully completed by HOD methods and two were completed with open cut methodologies with all completion dates meeting the required in-service date.
This article will discuss the challenges faced during both the design and construction phases of the shore approach crossings.
Sam Wilson P.Eng, CCI Inc, Edmonton, Alberta
Jeff Miller E.I.T., CCI Inc, Edmonton, Alberta
Adam Van Nood, Marathon Underground, Ottawa, Ontario