Construction of the Trans-Alaska Pipeline System with the Denali Fault, a major cause of earthquakes, and with large amounts of permafrost. In 1969, the unincorporated Trans-Alaska Pipeline System group drilled a series of core samples north of the Brooks Range that demonstrated how ubiquitous the permafrost was along the route. This forced the design of an elevated pipeline, which was tested in a loop built near Barrow. This elevation required the pipeline to be insulated, since extreme cold temperatures caused the metal to become brittle, even when hot oil was being pumped through the pipeline. After ecological objections forced subterranean pipeline crossings (in order to allow
CLH Pipeline System the WW2 cross-Pennine pipeline was found to be badly corroded and in the 1950s a new pipeline was built from the Stanlow area to the Humber. New storage depots were built on this pipeline and a third new import facility was constructed on the Humber. The first commercial usage of the system was immediately after the war to supply a depot on the River Severn from Avonmouth. In the early 1950s some aviation fuel was pumped from Avonmouth to a depot on the Thames to supply Heathrow airport by road tanker from there. Esso also used the network to pump