Meet the Workers Inside a Giant Drill Burrowing Through Rock to Repair a Broken Tunnel

The mission? To repair a leak in the Delaware Aqueduct.

Inside Edition went hundreds of feet underground to get an up-close look at a $1 billion repair project on the biggest tunnel in the world.

The mission, which is being overseen the New York City Department of Environmental Protection, is to break through bedrock to fix a leak in the Delaware Aqueduct, the longest tunnel in the world, stretching 85 miles from upstate New York to the border of Manhattan.

“We're building a new tunnel right alongside the leaking section so we can take that section out of service forever and essentially do bypass surgery on the tunnel to make it work well into the future,” Adam Bosch, director of public affairs for the New York City water supply system, told Inside Edition.

The operation is like open-heart surgery hundreds of feet under the ground.

A massive machine operates as a 2.7 million pound drill and is over 21 feet wide, 470 feet long. Workers actually go inside the machine in order to dig through the rock. 

They've been boring through rock for a year and a half.

“It's been grinding and turning for 18 months and it just broke through the last few feet of rock,” Bosch said. 

“This is where we live, this is our job, this is what we do every day and we love it,” general foreman Sean Sladicka said.