On my daily commute along the pipeline construction route on Boot Road and Ship Road in Chester County, I started noticing a lot of wires running along the ground. They mostly ran parallel to the road, either along the shoulder or across people’s lawns and driveways. Where they crossed roads, they were heavily taped down and sometimes they ran in shallow grooves. They appeared just before the actual drilling started, and I assumed they had something to do with directional drilling for the Dragonpipe (Mariner East 2), but I didn’t know exactly what.

From researching on the web, I now know that the wires are “guide wires” for the horizontal directional drilling (HDD) process. And I now notice them in many places where I hadn’t noticed them before. I have seen them in parking lots and crossing paths in the woods. As it turns out, they are a critical (but easily overlooked) element in the guidance system for the drilling.

Determining the drill’s exact location. When the initial pilot hole for a pipeline segment is being drilled, it is important that it stay exactly on course. There are three reasons for this: it must emerge at the right location on the other end, it must not hit any other underground utilities whose position is known, and it must stay on a precisely known path so that the records from the drilling process will accurately reflect its location for the benefit of future drillers. (The state requires a permanent locator record for all underground pipes and utilities.)

The wires are part of an electromagnetic guidance system. Their signals are picked up by a receiver inside the drill pipe, right behind the drill bit. The signals are transmitted back to the drilling site, where they are processed to derive the exact location of the drill underground. If it starts to get off the intended path, it can be redirected. (See “how do you steer a drill?”.)

While the big equipment gets all the attention, these small wires—no thicker than your little finger—are just as important to successful drilling.

Got wires? One final note about the wires: if you find unexplained wires running across your property, and you did not give permission for them to be there, you can call the police and ask for them to be removed. If they remain, I am told you are free to remove them yourself. As one lawyer told me, “that is trespass, plain and simple”. But I’m not a lawyer—before you do anything, you’ll want to check with someone who is.