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 CLH Pipeline System The CLH Pipeline System (CLH-PS), formerly the Government Pipelines and Storage System (GPSS), is a United Kingdom pipeline system run by Compañía Logística de Hidrocarburos (CLH). The network at one time consisted of over of pipeline and 46 other facilities. However, several of these facilities were closed before the GPSS was sold in 2015 and a number of the pipelines were mothballed and later 'abandoned'. Earlier the total number of facilities on the GPSS was much larger than 46. For example, in 1989 there were 40 Petroleum Storage Depots in operation plus large numbers of other facilities