LOS ANGELES (AP) Crews are nearly finished drilling 70 exploratory holes across the city’s west side — the first step toward building the long-awaited subway to the sea to help unclog traffic in one of the most congested areas in the nation, officials said.

Crews drilled up to 80 ft. (24 m) into the ground to assess soil conditions and determine how to best start digging a tunnel, Mayor Antonio Villaraigosa told reporters at a drilling site in Westwood.

The completion of the proposed 12.5-mi. (20 km) line linking downtown to the beach in Santa Monica could create about 16,000 construction jobs, he said.

“We’re not just digging for a tunnel. We’re digging for the most precious treasure any city can hope to discover during this tough economic time: we’re digging for jobs,” Villaraigosa said.

The line beneath Wilshire Boulevard is expected to cost an estimated $6.1 billion. An additional segment across West Hollywood would cost another $3 billion.

About $4 billion in funding will come from the county’s half-cent sales tax for transportation projects that voters passed last November.

Villaraigosa said the line could be completed in 10 years if local governments can secure enough federal funding to expedite the project.

“I’m 56 now,” the mayor said. “We are here today to make sure that it gets built before I am 66.”

Exploratory drilling for the subway line last occurred in the 1980s, but the ambitious project was stalled after a 1985 methane gas explosion demolished a clothing store in the Fairfax district.

The next year Democratic congressman Henry Waxman, whose district includes West Los Angeles, pushed through a federal ban on tunneling through the area.

Two decades later, he said new research convinced him that tunneling can be done safely. His bill to overturn the ban was approved by Congress in 2007.

The Metropolitan Transportation Authority said the line could draw up to 79,000 riders a day and add a crucial link to the area’s light-rail system that now covers 73 miles to Long Beach, Pasadena, the San Fernando Valley and communities around Los Angeles International Airport.

A 6-mi. (9.6 km) rail extension to East Los Angeles is expected to open in the fall.

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