LOS ANGELES _ 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 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.
In 2021, commuters will follow their steps, barreling through an S-shaped tunnel _ the $1.75-billion Regional Connector Project. The transit corridor will allow riders, for the first time, to travel from Long Beach to Azusa, and Santa Monica to East L.A. without changing trains _ filling a critical gap in Los Angeles' subway system.
Construction workers will dig 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.
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 challenges, the on-the-spot repairs. They like the community.
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 California Delta. For those willing to travel, the world is in play.
Tunnels are turning Earth into an ant farm with huge projects in progress 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, a 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, said Richard McLane, chief mechanical engineer for the Regional Connector Project.
"Why is tunneling so addicting? It's like watching civilization in action," McLane said. "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."
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.
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 said.
Halsey first stood at this console in 2004 when he took his inaugural run into Boyle Heights under Mariachi Plaza for the Gold Line. Never having operated equipment so demanding, he remembers shaking with adrenaline.
He and his wife live on a cul-de-sac in Santa Clarita, but he has done his share of traveling for the job, most recently to Washington where he experienced history from 130 feet deep, tunneling under the Potomac River ("that George Washington crossed") and near the air field where Obama's helicopter was hangared.
That soil, he said, was the best he has ever found: clay with layers of sand.
Halsey is a member of the International Union of Operating Engineers Local 12 and earns nearly $50 an hour, not counting overtime. He got his start in tunnels almost 20 years ago when he was in his early 30s, having worked road maintenance after graduating from Sylmar High School.
With its heavy machinery, cranes, loaders and excavators, the underground world was a big kid's dream, he said.
The ancient Persians pioneered tunneling techniques for transporting water, and the Romans added fire-quenching _ heating subterranean rock with fire and dousing it with cold water to encourage cracking _ to the engineer's repertoire.
Los Angeles was once considered an unlikely place for such grand ambitions, the soil deemed too gassy, too unpredictable.
A methane explosion in a water tunnel in Sylmar in 1971 killed 17 miners. In 1985, underground gas accumulated in an L.A. store at and when it blew up, nearly two dozen people were injured, leaving many to question the wisdom of building a regional subway system.
Gas wasn't the only problem for the city's first underground. In 1994 as Red Line crews burrowed beneath Hollywood, its boulevard sank 10 inches, and two years later, the 101 freeway dropped nearly four.
Not long after, a new style of tunneling machine came on the scene as the Metropolitan Transit Authority built the Gold Line.
By keeping steady pressure on the earth while excavating, operators minimized subsistence and heaving _ sinking and bulging _ the twin evils of tunneling, and with the miners enclosed in a capsule the diameter of the tunnel, dangerous gases could more easily be vented.
With the old equipment, the ground might move as much as an inch and half, McLane said. On this project, sensors have picked up movement of no more than 0.16 inches.
Mother Nature was not kind to them during the first month of tunneling as they clawed through the sand and gravel deposits of the ancient floodplain of the Los Angeles River. Five feet took them nearly two and a half hours as they advanced under the Japanese Village Plaza in Little Tokyo.
When the miners finally hit the silt and clay, a stratum of earth known as the Fernando Formation, they broke out in song. ABBA provided the melody:
We mined all night,
and we could not find ...
Fernando.
By then they were under Second Street with few obstacles in their way. Up ahead, at Hill Street, they will come within 6 feet of the Red Line tunnel, and as they close in on the station at Second and Hope streets, they will have a target to hit and can be off by no more than four inches.
The Romans drilled vertical shafts at close intervals and used plumb lines to keep their tunnels going where they wanted. A laser navigation system keeps the city's miners on track.
Early afternoon, and the work has assumed an easy rhythm. A dusty haze drifts through the tunnel. The miners fill water bottles from Igloo coolers and grab foil-wrapped plates of chicken or leftover spaghetti that they'd been warming on the electric motors that drive the hydraulics.
After replacing a gasket on the erector, repairing an overhead crane, cleaning a clogged port for the grout and clearing an overloaded hopper, they have the tunneling machine grinding away, like a finicky car finally on track.
Drawing on the lose coils of a chain winch, Jose Bautista muscles a fresh 50-gallon drum of tail-skin grease under pumps that will push it between the tunneling machine and the concrete rings. Bautista is an apprentice mechanic, his father a supervisor on the day shift.
Outside the tunnel, Alex Barajas helps load and unload the trucks that deliver the tunnel rings. His father is a foreman on the night shift. tried to discourage him from the tunnels, but a $100 award for every A wasn't enough to keep him in school.
When he was younger, Barajas used to unlace his father's mining boots at the end of a shift, and he would visit his father at tunneling projects around the country. "Without even knowing it, I was encouraging him to become a miner," his father said.
