User #1: Anybody care to share their thoughts on whether or not this is an operationally practical approach to locating buried obstacles?
User #2: I think it depends a lot on the dirt you are digging. If the dirt is fairly soft and rock free, then you can feel iron pretty easy. If the soil is rocky, you can't feel [anything].
I had to dig about a mile of trench connecting buildings. There were a lot of water lines that weren't marked, and I felt every one of them and broke none. I knew there were some unmarked water lines and was trying to feel for them and not digging as fast as I might if I wasn't expecting something. I did punch my teeth through a plastic drain pipe before I felt it. It was softer than the surrounding dirt so I couldn't feel it until the teeth were through it and the bucket contacted it. I ran into a little sand at one point and stopped and probed and one-half inch lower was a newer plastic gas line with a tracer wire that was missed when they marked the underground utilities.
User #3: We'll typically pothole by hand to find marked lines and then continue trenching under the utility via backhoe and shovels combined.
We have found in trenching operations with backhoes that if we take long, shallow passes that fill the bucket with crumbs as opposed to a massive hog-out, that helps us to be a little luckier in finding pipes/cables that are unmarked without damaging them. I'm still fighting this battle in my mind, because digging around such obstacles has been a major production dropper for us, and most of this stuff is not usually on the plans.
User #4: You can feel old steel gas lines pretty easy, same for ductile water lines, anything else is pretty tough. Usually find the old trench line, or if the material you are digging gets soft or you find some sand, that gives it away.
User #5: [I] had a 4" sewer line to put in and connect to main. It was about 300' of trench to dig. Running the whole length of the trench was a direct bury phone line that ran the fire alarm to the building.
I told the plant manager that chances of me not hitting the phone line was not very good. He said, "if you hit the phone line, the plant will pay to have it fixed."
After digging the whole trench [up to the last] 10 feet, the line was so old that it was broken by the shovel my guy was using when he was digging it up. The repair cost $1,100.
Worked for free that day. If you hit it, you will pay to fix it. Next time I will get it in writing or put my machine back on the trailer.
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