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There’s an underwater cable connecting SLO County to China. AT&T plans to yank it out.

The dark red lines indicate the rough locations of the cable sections that are part of the China-U.S. Cable Network that may be pulled out in early 2018.
The dark red lines indicate the rough locations of the cable sections that are part of the China-U.S. Cable Network that may be pulled out in early 2018.

At the turn of the century — when corporations raced to build global information superhighways — a fiber optic cable network was installed on the seafloor of the Pacific Ocean from Montaña de Oro to China, 6,000 miles away and beyond.

Now, the company that built it wants to take part of it out, saying it’s obsolete.

How are they going to do it? In short, the company plans to use a power winch on a ship named Layla to pull up sections of two cables that reach from the park to a water depth of 1,000 fathoms (that’s 6,000 feet) or about 55 miles offshore. That happens after the cables are found 3 feet under the seafloor and the ends have been cut.

AT&T published the plan when it submitted a notice of intent to the California State Lands Commission, whose members will talk about the proposal at a meeting Wednesday in Fresno.

When the commission approved the project in 2000, it required that AT&T remove segments of the cables to a depth of 1,000 fathoms when they were no longer needed. And although the cables were expected to operate for 25 years, AT&T says they are already obsolete.

Park users could be impacted by the work that would take place in early 2018. For instance, the onshore part of the effort will take up about half of the 50 parking spaces in the Sanspit Beach parking lot for a week or two while a contractor digs a 6-foot-wide and 20-foot-long trench there.

Local fishing activities also will be temporarily limited during the work because boats unrelated to the project will have to stay at least a mile away to avoid project delays or unsafe situations.

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The sand spit Parking in Montana de Oro State Park lot will be affected by removal of a fiber optic cable. Jayson Mellom The Tribune

AT&T’s proposal doesn’t say why the cable sections are obsolete, but according to a Federal Communications Commission public notice, the China-U.S. Cable Network was retired from service in December 2016.

In total, the 18,600-mile, $1.1 billion cable paid for by an international coalition of telecom companies connects the United States with China, Japan, Korea, Taiwan and Guam in a loop and had a capacity of 80 Gigabits, or 100 million phone calls at a time, according to a website that tracks submarine cable networks. The cables connect into a greater system at an AT&T terminal building about 10 miles inland on Los Osos Valley Road.

At least twice in the network’s life service was interrupted when a cable was cut by fishing boats dropping anchor off the coast of Shanghai.

These aren’t the only submarine cables in San Luis Obispo County.

The Pacific Crossing and Pan-American Crossing reach the shores of Grover Beach, while the Japan-U.S. Cable Network and another trans-Pacific cable network all meet under a manhole in the Sandspit Beach parking lot.

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Various trans-Pacific cables connect to the U.S. system under Sandspit Beach in San Luis Obispo County. Map by Padre Associates, Inc.

To make sure AT&T cuts the right cable, it plans to use survey records, and technicians may inject an inaudible 25 Hertz test tone signal onto the copper conductor of the cable that can be picked up by something called a magnetometer on the cable recovery ship. The location will be marked by buoys.

Once the ship is positioned offshore on the cable route, an onshore crew will pump air through a bore pipe and divers will follow air bubbles to locate and expose the end of the pipe that holds the cable.

After crews untrench and then reel up the cables in a series of maneuvers, the once cutting-edge technology will temporarily be stored onshore before they’re moved onto another ship to be transported to a cable recycling facility in Cape Town, South Africa.

As for the rest of the cables? They’ll be left on the seabed, the plans say.

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