Timeline projections have shifted considerably since the project broke ground in November 2007, when managers predicted opening to traffic in 2010.
Pushing into and through the unknown makes scheduling tricky, managers say.
  
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Planners are now shooting to be “done, done” with the tunnels – “I’s dotted, T’s crossed” – in early 2012, said Bob Haus, a spokesman for Caltrans.
Last week managers said the northbound tunnel was 55 percent complete and the southbound tunnel 52 percent complete. Der said the contractor, Kiewit, has spent $122 million of roughly $340 million budgeted for the project, keeping it on track, financially.
After installing a massive ventilation system in the tunnels earlier this year, and pushing past the halfway mark in both tunnels in March, nothing stands between the miners and the completed bridges on the north side except thousands of tons of rock.
That may sound calculable, but the final stretch of the path – the so-called North Block – looks to be the toughest, says Caltrans Senior Structures Representative Ivan Ramirez.
“The ground is what we expected, but we didn’t (know) how much of what kind of ground we were going to find … North Block is going to be the most challenging because it’s fractured and sheered,” he said, adding that rock in the North Block is comprised mainly of sandstone, shell and conglomerate.
Miners are finding surprisingly low levels of groundwater as they push and probe into the depths of the mountain, a factor favoring smoother drilling.
“Water is the No. 1 enemy of drilling,” Ramirez said, surmising that drier conditions inside the mountain could be symptomatic of the drought.
Still, water constantly seeps into the tunnels from above, places where workers haven’t sprayed a layer of hard surfacing mix – called “Shotcrete.” The water drips and coagulates into muddy puddles near the faces inside both tunnels. The rhythmic click-clack of industrial water pumps echoes throughout the tunnels when the diggers aren’t clawing through fresh sediment. When they are, workers are advised to put in their soft earplugs and wear sound-reducing earmuffs to block out the piercing reverberations. They employ special hand signals and body language to communicate over the noisy machinery.
Stepping into the tunnels through the “South Portal” the air grows dank, and natural light surrenders to bulbs emitting a dazzling yellow glow. Massive tractors and diggers lay dormant, lining the walls like dinosaur fossils unearthed during the course of excavation.
“They haul the tunnel muck up to the disposal site,” said Caltrans Safety Corridor Coordinator Jeff Kraus, pointing to a crusty dump truck on a trudge toward the rock face of the northbound tunnel on a cool, foggy afternoon in May.
Workers truck the dirt out of the tunnels, around a bend and up a cliff side to deposit and spread it across a flattened area they call the disposal site. The site is designed to hold all the muck extracted from the tunnels – about 400,000 cubic meters worth.
Kraus marched through the northbound tunnel to the face – about 705 meters deep – where miners were probing 60 feet into the rock to get an idea of what material lays ahead.
At the other side of the mountain, where the bridges meet the northern slope, tractors are rearranging dirt and building a soil nail wall as reinforcement for the day miners break through.
On a peak day of work, about 300 people grind away to keep the wheels turning at the tunnels project, Kiewit Project Manager Scott Wimmer said. Planners, managers, engineers, administrators, contractors, supervisors and miners work round the clock six days a week. Some stay on the Coastside while others commute, some from as far as the northern reaches of Oroville and the Sacramento Valley.
Leaders, engineers, contractors and miners came together Tuesday for a monthly mass safety meeting to celebrate more than two months of “accident-free” digging into the belly of the mountain. It’s a brief gathering, Wimmer said, “then everyone goes back to work.”
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