Trans-Alaska Pipeline

The 800-mile Trans-Alaska Pipeline (Alyeska Pipeline) cost $8 billion to construct and was completed in 1977.

The Prudhoe Bay oil fields on Alaska's North Slope had been mined by the local Inupiat people for the oil-saturated peat for use as fuel for heat and light, possibly for thousands of years. The oil field is the largest in North America, originally containing some ten billion barrels of oil. The source of the oil is the Jurassic-era Kingak shale layer, which is rich in organic matter. In the field oil is moved through pipelines from about a thousand wells to a pumping station at the head of the Trans-Alaska Pipeline.

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Prudhoe Bay (Sagavanirktok) supports the Prudhoe Bay oil field. The airport, lodging, and general store are located in Deadhorse. The area was developed to house personnel and support operations for the Trans-Alaska Pipeline.

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Pipeline views:

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Pipeline details:

Pipeline pigs are inserted into and travel through the pipeline driven by the flow. They are used to remove waxy deposits that obstruct or retard the flow. Pipeline pigs do most of the maintenance. Pipeline pigs also look for corrosion and check for bending or buckling. The name comes from the squeaking noise the devices make. Pigs are inserted at Prudhoe Bay and travel the whole length of the pipeline, or at a pump station near its midpoint.

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The 48" pipeline has pipeline sliders to resist earthquakes and temperature-related expansion and contraction. The elevated portions of the pipeline rest on H-shaped supports eight feet above the ground. Where the pipe meets the crossbar, it is attached to a Teflon-coated shoe that free-floats on another Teflon shoe, allowing the pipe to move slightly to the left or right without damage.

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The zigzags also allow for expansion and contraction due to temperature changes.

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Heat pipes conduct heat from the oil to the top of the pipes to heat fins to avoid thawing the permafrost. The heat pipe posts contain a liquid that has a very low boiling point and high vapor pressure. The liquid boils at a temperature below the freezing point of water. When heat is transferred to the liquid at the bottom of the post, it boils, changes to gas, and rises to the top, where the heat is released into the atmosphere through the radiator fins on top. The liquid then drips back down to the bottom of the post.

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There are 579 animal crossings to allow large game to cross the pipeline, 554 of them elevated to at least ten feet, and 25 buried, two of which are refrigerated to protect the permafrost:

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The pipeline passes underneath many smaller rivers and streams but bridges longer crossings. The pipeline crosses thirty-four major streams or rivers and nearly eight hundred minor ones.

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The Yukon River bridge was a major engineering feat.

Pumping stations maintain the momentum of the oil as it goes through the pipeline. The oil flow averages five to six miles an hour.

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The pipeline is surveyed several times per day, mostly by air. Surveying can be done in as little as two hours.

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Last modified 13 September 2016