Northstar Island

[1] The island was created to develop the Northstar Oil Pool, which is located approximately 12,500 feet (3,800 m) below the seabed.

[1] A standard oil-drilling platform, such as those used in the Gulf of Mexico, was not feasible because of the annual formation of pack ice close to the northern Alaska coast.

[4] During the first winter of construction, more than 700,000 cubic yards (540,000 m3) of gravel was brought in from the Alaska mainland over ice roads to bring the island above sea level.

To reach the seabed, workers had to cut blocks of frozen Beaufort Sea ice and remove them with cranes.

[6] By the time the winter ice melted, the island was above sea level, and both pipelines were in place and tested.

[12] Specialized leak-detection equipment and sensors had to be developed to prevent problems with the unique undersea pipeline employed by the project in the Beaufort Sea.