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| Down the Deep Tunnel, 1999 |
The Deep Tunnel is a vast, 110-mile-long, 30-year-old, $3 billion-dollar project. It isn't yet done and already it is proving insufficient to the task of draining the climate-change-stoked rains hitting Chicago. According to a story Tuesday in the Sun-Times, the tunnel is getting fuller faster. That's bad news, particularly for homeowners in the Southwest suburbs, whom the Deep Tunnel was supposed to protect from flooding.
I've been down the Deep Tunnel, twice. Once when they were flooding the Thornton Quarry in 2015. And for the first time in 1999, a story not posted here before:
In 2005, in the basement of a house that hasn't been built, the possessions of a boy who hasn't been born will stay nice and dry during a major rainstorm because of work going on right now 310 feet under Torrence Avenue.
The second-to-last leg of the Deep Tunnel Project is creeping slowly forward, a foot at a time, as a gigantic digging machine eats into the dense dolemite limestone.
Work is conducted 24 hours a day, seven days a week, by two dozen miners who, with their beards, coveralls and miner's helmets, are a vision from Harlan County, Ky., working to bring Chicago into the 21st century.
The Deep Tunnel began 93 miles and 27 years ago. Every four days, on average, rainwater would back up a sewer system somewhere in Chicago, sending raw sewage spilling into the already polluted Chicago River. The tunnel was conceived as a man-made underground river to carry away storm overflow.
"This is the second greatest accomplishment in our history," said new Metropolitan Water Reclamation District Commissioner Martin Sandoval. "The first was the reversal of the river."
The Deep Tunnel is so vital to the growing Chicago area that when a small section collapsed in June, beaches were closed and water supplies were compromised. Interest in the unseen tunnels grew after that, and the Water Reclamation District invited the media down Wednesday to see what they are up to.
Digging, mostly. To get to the digging, you step into a circular yellow metal cage, big enough for four people, that is lowered into a hole in the ground.
The cage touches ground in a cavernous area, blasted from the rock, where the gigantic digging machine was lowered and assembled in 18 separate pieces. An electric train takes miners to the machine, two miles away and moving forward at nearly a mile a month.
The noise is tremendous. Forty-seven cutting heads spin into the limestone across a rotating circle 27 feet wide. Every 7 feet, the machine releases a pair of "gripper pads" — disc-brakelike devices, 5 feet wide, that push out against the walls of the cave to keep the machine from spinning — and moves forward. The pads reset, and the digger's spinning face grinds onward.
Miners must be alert. Sensors monitor for methane gas. They run into fault lines, or different types of rock — 1,800 feet of the tunnel had to go through shale, which is not as strong as the limestone, and the roof of the tunnel had to be specially reinforced as the machine moved forward, to avoid collapse.
Meanwhile, miners atop the drill bore a pair of 5-foot-deep holes into the roof and attach a semicircular metal band with 5-foot-long hollow metal rods that are driven into the holes, spreading wide to set into the stone and help support the ceiling, which feels wet and crumbly.
Along the length of the two miles, groundwater glistens on the walls and occasionally pours in cascades that will be shut off with grout before the interior of the tunnel — a blanket of concrete a foot thick — is poured. The crushed rock is removed by a conveyor belt and sold.
Not only will the Deep Tunnel keep basements dry and the Chicago River pure — a bass fishing contest will be held on the river next year — but it also provides a good source of crushed limestone. The new United Parcel Service facility at 75th and La Grange is sitting on stone from the Deep Tunnel.
The second-to-last leg of the Deep Tunnel Project is creeping slowly forward, a foot at a time, as a gigantic digging machine eats into the dense dolemite limestone.
Work is conducted 24 hours a day, seven days a week, by two dozen miners who, with their beards, coveralls and miner's helmets, are a vision from Harlan County, Ky., working to bring Chicago into the 21st century.
The Deep Tunnel began 93 miles and 27 years ago. Every four days, on average, rainwater would back up a sewer system somewhere in Chicago, sending raw sewage spilling into the already polluted Chicago River. The tunnel was conceived as a man-made underground river to carry away storm overflow.
"This is the second greatest accomplishment in our history," said new Metropolitan Water Reclamation District Commissioner Martin Sandoval. "The first was the reversal of the river."
The Deep Tunnel is so vital to the growing Chicago area that when a small section collapsed in June, beaches were closed and water supplies were compromised. Interest in the unseen tunnels grew after that, and the Water Reclamation District invited the media down Wednesday to see what they are up to.
Digging, mostly. To get to the digging, you step into a circular yellow metal cage, big enough for four people, that is lowered into a hole in the ground.
The cage touches ground in a cavernous area, blasted from the rock, where the gigantic digging machine was lowered and assembled in 18 separate pieces. An electric train takes miners to the machine, two miles away and moving forward at nearly a mile a month.
The noise is tremendous. Forty-seven cutting heads spin into the limestone across a rotating circle 27 feet wide. Every 7 feet, the machine releases a pair of "gripper pads" — disc-brakelike devices, 5 feet wide, that push out against the walls of the cave to keep the machine from spinning — and moves forward. The pads reset, and the digger's spinning face grinds onward.
Miners must be alert. Sensors monitor for methane gas. They run into fault lines, or different types of rock — 1,800 feet of the tunnel had to go through shale, which is not as strong as the limestone, and the roof of the tunnel had to be specially reinforced as the machine moved forward, to avoid collapse.
Meanwhile, miners atop the drill bore a pair of 5-foot-deep holes into the roof and attach a semicircular metal band with 5-foot-long hollow metal rods that are driven into the holes, spreading wide to set into the stone and help support the ceiling, which feels wet and crumbly.
Along the length of the two miles, groundwater glistens on the walls and occasionally pours in cascades that will be shut off with grout before the interior of the tunnel — a blanket of concrete a foot thick — is poured. The crushed rock is removed by a conveyor belt and sold.
Not only will the Deep Tunnel keep basements dry and the Chicago River pure — a bass fishing contest will be held on the river next year — but it also provides a good source of crushed limestone. The new United Parcel Service facility at 75th and La Grange is sitting on stone from the Deep Tunnel.
—Originally published in the Sun-Times, Oct, 21, 1999
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