In 1973, Elden Johnson was a young engineer contributing to one of the world’s most ambitious projects: the trans-Alaska pipeline. This 800-mile steel pipeline carries warm oil across the challenging terrain of frozen ground in Alaska. Years later, Johnson reflected on this monumental project, calling it ‘the greatest story ever told of man’s interaction with permafrost.’
Stretched from Prudhoe Bay to Valdez, the 4-foot diameter, half-inch thick steel pipe has outlasted its original 30-year design lifespan. Both the state of Alaska and the U.S. Department of the Interior have authorized another 30 years of operation for the pipeline. Johnson noted the importance of maintenance, likening the pipeline to a car: ‘As long as you maintain it, it’ll continue to work.’
A significant challenge the project faced was the presence of permafrost, which exists beneath approximately 75% of the pipeline’s route. Thawing ice-rich permafrost leads to ground instability, resulting in serious issues for structures built above it. In the wake of the 1969 oil discovery at Prudhoe Bay, early developers intended to bury the pipeline entirely. However, experts knowledgeable about permafrost dangers recommended a different approach.
As a result, about 380 miles of pipeline were buried, whereas approximately 420 miles were elevated on supports. Although the initial design was solid, Johnson recalls moments of concern during construction when they discovered unstable permafrost along the route from the Yukon River to Coldfoot. This led to critical redesign recommendations for about 20% of the pipeline.
Johnson, who worked for Alyeska Pipeline Service Co. until his retirement in 2008, described these decisions as ‘gut-wrenching’ given their potential impact on the project’s schedule. The choice to elevate portions of the pipeline was ultimately justified when, just two years after its launch in 1979, the buried sections buckled and leaked due to thawed permafrost. The warm oil within the pipeline—exiting Prudhoe Bay at about 145 degrees Fahrenheit—caused significant ground settlement.
Engineers promptly repaired these issues and continued to monitor the pipeline’s condition. Alyeska contractors consistently check for signs of settling and ensure the efficient operation of heat pipes that stabilize the support posts of the above-ground sections. Johnson observed that as time has progressed, the initially rapid thawing has stabilized, further solidifying the condition of the buried pipeline. ‘The risk to the buried pipeline right now is becoming minimal,’ he remarked in 2008.
Since its startup in June 1977, the pipeline has successfully transported over 18 billion barrels of oil, with only two brief shutdowns attributable to permafrost issues. Johnson estimates that maintenance related to permafrost has comprised approximately 5% to 10% of the total operating costs throughout the pipeline’s life. ‘It’s the cost of doing business in the Arctic,’ he concluded, highlighting the ongoing challenges and triumphs of engineering within this unique environment.
image source from：https://www.adn.com/alaska-news/science/2025/05/30/how-a-young-engineer-navigated-permafrost-to-develop-one-of-most-ambitious-and-uncertain-projects-in-the-world/
