For more than a mile through this remote pass, avalanche dangers and unstable soil conditions required special construction techniques to be used. About 6, 000 feet of the ditch was lined with a concrete base, and the pipe encased in an insulation box to keep the soil frozen when hot oil enters the line., 1977-01, PCA0002-4a-11, Folder: PCA0002-4a. Alyeska Pipeline Service Company : Trans-Alaska Pipeline Construction Collection, 1976-1977, PCA 2. Alaska State Library - Historical Collections Finding Aids. https://alaska.libraryhost.com/repositories/2/archival_objects/17722 Accessed February 22, 2025.