Deep Drill Solves City’s Water Main Crisis

Under The Boise River
December 2012, Vol. 67 No. 12

“The Boise River water main install is probably the most challenging bore that we’ve been contracted to do so far,” says Mace. “We recently completed one with the same drill, a couple weeks before, that was installing 1,100 feet of six-inch conduit. Being only a 650-foot install, this project is shorter, but a 20-inch water line brings its own unique set of issues.”

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Because the project went under the Boise River, there were some environmental concerns, as well as the depth and the size of the water line. “It’s not too common to pull back something of that size at that distance, particularly with all the backreaming we needed to do and in the rocky riverbed conditions that we’re working in,” he says.

According to Mace, Track Utilities role was to get the new water line installed underneath the Boise River. The entry and exit pits were designated in the city’s project plan, so Mace and his team knew where they had to go into the ground and where they had to come out. The city’s plan also required the crew to set up close to the banks of the river to prevent traffic and pedestrian concerns.

“It was a fairly technical bore,” says Mace. “To get the right arc on the line, we had to bore deep in the middle of the river, about 50-feet down.

“The ground and terrain conditions on this bore were also extremely tough,” he continues. “There were lots of big rocks and pit run to bore in and through. The city’s mandates on certain elements of our setup and operations really helped us build our profile and understand what we were going to be working in to begin with.”

Complications
Because the project commenced during the spring plus the depth the line needed to be installed, one of the major challenges of the project was that the water levels were extremely high on the Boise River. Track’s crew could not locate the bore with a locator from the top of the ground like they would normally do. “To locate, we brought in a wire line system to guide us through and under the river,” says Mace.

On this project, Mace and his crews employed their D80x100 Series II drill, one of five Vermeer horizontal drills they currently have in their equipment fleet. “We chose this drill because it’s the biggest one that we have, and with our operator’s ability, we were pretty comfortable that it would shoot 650 feet across that river and be able to pull back the 20-inch water line,” says Mace.