AS116: In the foothills of the Brooks Range, from 3 to 4-1/2 inches of the polystyrene were placed in layers within the work pad. On the rolling tundra north of the range, insulation thickness ranged from 3 to 4 inches, and on the flat coastal plain from 1-1/2 to 3 inches., 1976-05, PCA0002-1b-59, Folder: PCA0002-1b. 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/17397 Accessed February 22, 2025.