SEATTLE (MCT) — A potential new energy frontier opened early Sunday in the U.S. Arctic as Royal Dutch Shell plumbed a drill bit into the bed of the Chukchi Sea, 70 miles off the coast of northwest Alaska.

The oil company, which spent six years and $4.5 billion trying to launch America’s first offshore oil production in the Arctic, announced that its Noble Discoverer had anchored northwest of Alaska’s North Slope and begun drilling the “top hole” of an exploration well. The work was the first step toward drilling a pilot hole that will go about 1,300 feet deep.