Oil and the Trans Alaska Pipeline

Introduction
The largest oil field in North America was discovered at Prudhoe Bay on the North Slope of Alaska in 1968. After environmental concerns were met and Alaska Native land claims were decided, an 800 mile long pipeline was laid from the North Slope south to Valdez, where an oil loading terminal was established. Construction was begun of the haul road to get supplies to the pipeline route, and the first pipe was laid in March 1975. The first oil flowing through the pipe reached Valdez on July 28, 1977.

70,000 people worked on the pipeline at various times. The greatest number of workers at any one time was 28,072. Workers lived in work camps, often working seventy and eighty hour weeks. The Pipeline took three years and two months to build. It crosses three mountain ranges and bridges thirteen rivers. It is buried under many other streams. The pipeline is built to move but not rupture in an earthquake. The vertical supports contain heat exchanger units to ensure that the permafrost over or in which the pipe is laid will not melt. In order to build the pipeline 515 federal permits and 832 state permits were required, and obtained. It cost eight billion dollars to build and remains one of the largest construction projects ever completed.

The pipe is 48 inches in diameter. The oil inside the pipe comes out of the ground at temperatures as high as 145 degrees Fahrenheit and it sent through the pipe hot. The interior of the pipe is cleaned by sending a “pig” periodically through it. The pig, which can be seen in the cut-away of the pipe, tests for corrosion and any changes that are occurring in the pipe.