A welcomed "Mole" in my side driveway and backyard

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I wanted the galvanized domestic water lines to our house replaced with copper. Our house was the middle house of a series built and everybody else has had their galvanized domestic water line rust out. Our galvanized "irrigation" water line has already rusted out.

So....I hired this guy to replace them. He digs a 3'x3'x3' hole every 30'or so and uses this pneumatic mole to drill a hole and when it comes up at the other end, he puts a rope in the hole at it's nose. He then reverses direction and it backs out with a line attached to pull a steel cable through the hole. To that he attaches the copper line and pulls it through. To reverse direction, he twists the air hose about 4 turns in the other direction and it reverses it's direction.

Pretty neat.

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Actually.....he aims it at the next hole...... 30 or so feet away......and his only concern is to keep it level as it digs from the current hole. In one photo you can see him with his foot on top the tool. It hit some hard earth and the back was kicking up so he held it down until the 4' length of the tool was completely in the hole. Then it just continues to "dig". It's acutually pounding internally like a pile driver does....it drives a hole horizontally.
 
Yes...you can feel it "hammering" in the ground by just walking over the earth. I am deaf and coulf barely hear it once it got totally inside the hole it was pounding but you can definitely feel it and accurately tell it's current location. I did it just out of curiosity.
 
3ft deep!?!? wow, what is your frost line there?

My water line comes UP through the floor of the basement, so that is at least 6-7ft down in the ground...


...art

ps: ditto what Brent said about the pristine clean hole!
 
Art....city code is 3'. I would bet our frostline is at best 18" maybe less. We sit in the Lewis-Clark Valley and the temperatures are relatively mild compared to the surrounding country.
 
We used one of those about ten years ago to drag a 3" PVC pipe (for a commercial irrigation system) under a four lane street. It took less than half a day. Amazing to watch, too!
 
We used a machine to do almost the same thing when I worked for a gas pipeline company. We drove 12" steel casing under a road, but our machine also had an auger to draw out the dirt from the inside of the pipe. It was amazing to see the pipe disappearing into the ground from the trench we had to start in. Then when it got almost all the way in, they stopped, pulled the driver and auger off and I welded the next section of pipe on and it began again. That was back in New York state.

Aloha, Tony
 
We used a machine to do almost the same thing when I worked for a gas pipeline company. We drove 12" steel casing under a road, but our machine also had an auger to draw out the dirt from the inside of the pipe. It was amazing to see the pipe disappearing into the ground from the trench we had to start in. Then when it got almost all the way in, they stopped, pulled the driver and auger off and I welded the next section of pipe on and it began again. That was back in New York state.

Aloha, Tony

Back in my brief stint on a survey crew I did the layout and level survey for a 12" sewer line under a roadway that was done in a similar way. I staked out line and elevations, and the drillers did the hard part. It amazed me that they could drill upslope for 100 feet or so and be within a couple hundredths of a foot in elevation at the end of the hole.
 
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