Climb inside the massive tunnel 60 feet below downtown L.A.

Ten weeks in and 60 feet beneath the streets of downtown Los Angeles, the miners have clawed through nearly 2,600 feet of earth.

At 5 a.m. on a cool Thursday morning, they gather in the construction yard for the start of another shift.

The moon, just starting to wane, hangs above the distant skyscrapers as the men stretch like athletes and huddle to hear the latest safety report.

The day before, they had been unable to dig. Gas — most likely methane — had been detected in the tunnel, and they had to wait for state inspectors to give them the OK.

“It’s all good now,” their foreman announces, “but we’ll still be monitoring, so be careful.”

Coolers in hand, hard hats and fluorescent vests reflecting the glare of the light towers, they clomp down seven flights of stairs into a large open pit, shored up by wooden timbers and crowded with vats of grout, portable trailers and man lifts.

The mouth of the tunnel gapes at them. The moon, the clouds and the city disappear as they enter.

In 2021, commuters will follow their steps, barreling through an S-shaped tunnel — the $1.75-billion Regional Connector project — 1.9 miles out of Little Tokyo, north to Bunker Hill and west to 7th and Flower streets, a transit corridor that will link Long Beach to Azusa and Santa Monica to East L.A.

Construction workers will lay almost a mile of that tunnel through a methodical excavation of Flower Street, building the subway and then rebuilding the street. The rest, however, is being dug the hard way.

Take a 360-degree tour of L.A.’s Regional Connector Project

The miners, traipsing single file along a plank walkway, descend a gentle grade into the tunnel for nearly half a mile before reaching their destination: a 400-foot-long, 1,000-ton earth-chewing beast, known as the tunnel boring machine.

Sometimes called moles, sometimes sandhogs, the men — there are no women on this shift — belong to a tight confederacy. They can see themselves doing little else for a living. They like being left alone to do their job. They like the variety of challenges, the on-the-spot repairs. They like the community.

“There are no bad people down here,” said one miner. “We would throw them out if there were.”

Regional Connector project overview

Source: Metro Regional Connector Lorena Elebee / @latimesgraphics Little Tokyo 2nd/Broadway Station (new) Blue Line linkBlue Line continues to Pasadena along Gold Line route. Blue Line linkBlue Line continues to Pasadena along Gold Line route. Gold Line to East L.A. Gold Line to East L.A. Blue Line from Long Beach Blue Line from Long Beach To Santa Monica To Santa Monica To Pasadena To Pasadena This segment will be built by excavating the street, constructing the tunnels and rebuilding the street. 2nd/Hope Station (new) 2nd/Hope Station 2nd/Broadway Station 1st/Central Station The stations: Renderings of the stations under construction along the Regional Connector route. 1st/Central Station(new) Pershing Square 2nd & Hill L.A. TIMES CITY HALL BONAVENTURE HOTEL THE BROAD WALT DISNEY CONCERT HALL UNION STATION 7th/METRO CENTER RED/PURPLE LINE GOLD LINE Hope St. Flower St. Broadway Hill St. Grand Ave. Alameda St. Spring St. Main St. Los Angeles St Temple St. 1st St. Aliso St. 2nd St. 3rd St. 4th 5th St. 7th St. 101 110 Downtown Los Angeles Path of Tunnel Boring Machine 500 FEET Bunker HIll The Regional Connector line will link the Expo, Blue and Gold lines. Now, for the first time, riders can travel from Long Beach to Pasadena and from Santa Monica to East L.A. without changing

Regional Connector project overview

M 101 110 Little Tokyo 2nd/Broadway Station(new) To East L.A. To East L.A. To Long Beach To Long Beach 2nd/Hope Station(new) 1st/Central Station (new) L.A. TIMES UNION STATION RED/PURPLE LINE Flower St. 2nd St. 7th St. Downtown Los Angeles Bunker Hill To Pasadena To Pasadena The Regional Connector line will link the Expo, Blue and Gold lines Source: Metro Regional Connector Lorena Elebee / @latimesgraphics To Santa Monica To Santa Monica

Veterans of other tunnels, they have built passages for water to flow through the San Bernardino Mountains and under Lake Mead, and they look ahead to the possibility of digging beneath the streets of South Pasadena or in the Sacramento-San Joaquin Delta. For those willing to travel, the world is in play.

Tunnels are turning Earth into an ant farm with massive projects underway in London, New York, Hong Kong and Germany.

In Qatar, nearly 24 tunneling machines are digging a subway system for the 2022 World Cup, and in China, one company manufactures nearly 50 tunneling machines a year for that market alone.

As long as the world’s population continues to grow and cities become more congested, there will be a demand for tunnels and miners, says Richard McLane, chief mechanical engineer for the Regional Connector Project.

“Why is tunneling so addicting?” McLane asks. “It’s like watching civilization in action. This is not a leaf spring for a Chevy Camaro that in 10 years will be in a junkyard. The work we do will last generations.”

Engineer Frank Reddy monitors the placement of one of the concrete segments that line the tunnel.
Miners ride the locomotive out of the tunnel at the end of their shift.

All aboard the dirt-chewing machine

After a five-minute walk through the tunnel, the miners reach their destination and begin to spread out.

Inside the operator’s cab, a small air-conditioned box near the front of the tunneling machine, Scott Halsey faces a wall of monitors, one featuring video feeds of the conveyor belts, others relaying with rising and falling numbers the machine’s progress.

His hands are reflexively poised over rows of switches, dials, toggles and buttons lit red or green. He picks up the phone.

“OK, we’re good to go.”

Looking more like a computer technician than a miner, Halsey presses a series of buttons, and the numbers on the control panel begin to rise. Seventy feet ahead, far out of sight, the machine’s cutting head has begun to rotate.

Source: Metro Regional Connector (Stations not to scale) Wilshire Blvd. 1st/Alameda Station 2nd/Broadway Station Los Angeles St. Bunker Hill Hill St. Grand Ave. The tunnel at its deepest: 130 ft. The deepest station is 2nd and Hope: 110 ft. Regional Connector tunnel Red Line tunnels Lorena Elebee / @latimesgraphics 110 feet down to catch the train 118 ft. Olive St. 84 ft. Elevation profile

Hydraulic jacks push the cutting head forward and exert a steady pressure against the earth.

The cutting head grinds through the earth at two rotations a minute, shaving and clawing at a dense wall of clay and silt compressed over millennia. Every minute it advances three inches.

Auger screws churn the excavated soil — softened by a foamy mixture of air, conditioner and water to a Play-Doh-like substance known as muck — and conveyor belts transport it back to the pit and an armada of dump trucks bound for Irwindale.

The high-pitch whir of the cutting head echoes inside the tunneling machine along with the drone of the conveyor belts, motors driving the hydraulics, the hammering of the grease pumps and the occasional air-horn blast from an arriving locomotive that runs through the tunnel ferrying supplies and equipment.

“We’re mining,” Halsey says.