Shell's repaired icebreaker arrives at Arctic Ocean drilling site

A key emergency response vessel arrived at Royal Dutch Shell's drill site in the Arctic Ocean Tuesday night, inching forward the oil giant's plans for digging an exploratory well this summer.

With arrival of the Fennica, a leased Finnish icebreaker, final federal approval is the only hurdle remaining before Shell can expand its operation off Alaska's northwest shore and begin drilling into the layer of oil-bearing rock, which lies some 8,000 feet below the ocean floor.

Officials with the Bureau of Safety and Environmental Enforcement said they received Shell's application for deep drilling last week but there's "no timeline" for when a decision would be reached.

Gregory Julian, the federal agency's press secretary, said the two parties are communicating regularly to hammer out details of Shell's proposed plans and monitor ocean conditions. Shell did not respond to requests for comment Wednesday.

Last month, Shell received limited permission to bore holes at the top of two well sites at its Burger prospect 70 miles off Alaska's coast. But the oil company was blocked from drilling into hydrocarbon zones because a critical safety device, a capping stack, carried aboard the Fennica, was not on hand. The capping stack is a 30-foot piece of equipment that can plug a gushing wellhead underwater.

The icebreaker arrived Tuesday at the drill site after being delayed by repairs to its hull from damage the ship incurred July 3 on an uncharted shoal in waters near Dutch Harbor. Shell must keep the icebreaker nearby the drill site and ready to steer the capping stack into place within 24 hours of a blowout emergency.

Repairs for the Fennica were completed in Portland, Oregon on July 30, but activists with Greenpeace blocked the vessel by dangling from a bridge over the Willamette River using climbing ropes. The protest lasted a day and a half before authorities cleared the way for the Fennica to depart.

Environmental groups question safety measures for drilling and say Arctic oil activity will jeopardize marine mammal habitat for polar bears, walruses and ice seals that are already threatened by warming oceans and receding sea ice. Some opponents also say tapping Arctic oil reserves will set back efforts to transition the nation to renewable energy sources.

Shell's Polar Pioneer has carved out a 20-foot by 40-foot hole in the seabed atop the wellhead where a blowout preventer will be installed. The semisubmersible drilling platform is now on standby to begin deeper drilling into oil-bearing rock pending federal approval.

A second vessel, the Noble Discoverer, is stationed 8 miles away above another drill site.

The two vessels are not allowed to work simultaneously. To mitigate the impact of noise on the area's walrus population, federal rules bar rigs from drilling at locations within 15 miles of each other.

With ice in the Chukchi Sea anticipated to form at the beginning of November, the window for Shell's drilling work is closing. Federal rules mandate that work stops during a precautionary period of 30 days ahead of the expected ice season, which puts pressure on Shell to strike oil after years of investment.