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Mountain Pass Drilling: Contractor Beats The Snow To Install Fiber In Washington
Contractors involved in horizontal directional drilling (HDD) often must work through difficult projects, many with unexpected challenges. However, Oregon contractor Apex Directional Drilling has a history of seeking out complex projects that other HDD specialists are reluctant to take on.
A recent example is construction of a 71-mile segment of fiber optic cable – 37-miles of the project was underground in the Cascade Mountains of northeast Washington.
The project owner was the Northwest Open Access Network (NoaNet), Spokane, WA, a wholesale-only fiber backbone carrier that provides high-speed network connectivity to telecommunications companies, Internet providers, application service providers and cable companies throughout Washington state.
Apex was the general contractor and completed the underground segments. Aerial portions were subcontracted to Henkels & McCoy, said Scott Gagner, Apex project manager. The route of the project was along State Highway 20 from approximately 15 miles west of the town of Kettle Falls, WA, and ending in Tonasket, WA.
Gagner said of the 37 miles of underground inner duct, approximately 110,000 feet -- 21 miles -- was installed by horizontal directional drilling, with 100,000 feet installed through solid rock ranging in hardness from 15,000 to 30,000 psi. Excavation and vibratory plowing were used on the remaining portions of the underground work, primarily in areas where soil was softer and the terrain allowed space for equipment.
Starting at the top
Gagner said the plan called for construction to begin at Summit Pass which, at 5,700 feet, is the highest mountain pass in the state of Washington to stay open year round. From there, the work would proceed east, completing the highest and most difficult elevations before the first snowfall.
“Apex Directional Drilling was the first to install any underground utility over Sherman Pass,” said Gagner.
For HDD segments, Apex used relatively compact Ditch Witch All Terrain (AT) equipment which employs a dual-pipe mechanical drilling system, rather than larger machines with mud motors. This decision eliminated the need for support equipment required for mud motors and greatly reduced the volumes of drilling fluid needed for operations. Apex has successfully used this technique on projects in similar conditions,