Over the last several months, we’ve had the opportunity to see a couple of large utility projects going on right out our window. I know at least a few of us have been speculating about what the electrical project a couple of months ago was about, and lately what that pipeline project along Hungerford is. I’ve been very curious about it, and all the action happens during the daytime, when I’m at work.
After a lot of half-baked discussion and guessing about it while drinking soda pop on the front stoop with Brian, Jody, Mike and others, I finally walked across the overpass to look at the other side. After reporting back my findings, I think we have it figured out. They’re pulling a natural gas pipeline all the way under 496. There’s a horizontal directional drilling (HDD) rig on the south side of the highway, which bored a hole underneath the roadway to our side. For several weeks they have been welding up lengths of pipe into about 50-yard sections. Finally over the last few days they used the boring machine in reverse to pull the pipe through. I guess they pulled one section almost all the way underground, then welded on the next section, and kept pulling.
I found a few videos showing how it works. This one, https://youtu.be/L8r5pbxP4tg, shows a similar project. You can definitely skip ahead; it’s 13 minutes of slowly moving pipe. At about 8:00 minutes, it switches from the “down into the hole” side to the “up out of the hole” side. It’s kind of satisfying when the pipe finally emerges from the mud.
Another video, https://youtu.be/v_uMjo8XmnE, explains the boring machine, and how they can steer the drill bit to follow the path down, across, and back up. If you like professional narration about heavy construction equipment, this video is for you.
If you had asked me a few months ago if you can just pull a long 15" diameter pipe under a highway, I would have said no, you can’t. But it looks like you can.