May 2022 Vol. 77 No. 5
Features
Trenching Electric Conduit in New Mexico
Jeff Griffin | Senior Editor
While horizontal directional drilling (HDD) has had a massive impact on the underground construction industry, much of the underground pipe and cable continues to be installed in trenches dug by conventional equipment.
When soil conditions are right and disturbing the ground’s surface is acceptable or not an issue, trenching is the fastest, most economical way to make underground installations.
For example, Essential Utilities, a contractor serving electrical utilities and contractors, is nearing completion of a 12-mile trenching project to install conduit for primary electric cable for Public Service Company of New Mexico.
Most of the trenching is along road right-of-way in rural Santa Fe County. Other trenches are in easements on properties to reach individual transformers.
“A Trencor T1060 was used for long runs and a Ditch Witch RT120 rock saw and rock hammer with backhoe were used to cut trench to transformers on properties or in tighter spaces,” said Jason Pilnock, vice president of Essential Utilities. “A Ditch Witch rock boring machine is being used by one of our subcontractors to make road crossings.”
Soil conditions are mixed rock, with both basalt and granite-like rock.
“Conditions vary,” he added, “with some of it being solid, some broken, and some put back in the trench after blasting. Most of the trench was four-feet deep and 18-inches wide.”
Powerful machines
Trencor T1060 is a 350-horsepower, track-mounted trencher with chain-type trenching component. It can dig to depths of 14 feet, depending on the digging chain set-up.
The RT120 rock saw is mounted on a four-wheel drive tractor and was configured for this project to dig to about 31/2-foot depths, 8-inches wide.
“The hard rock slows the trencher somewhat,” Pilnock said, “but the most difficult areas so far are the blasted rock, as the trench collapses a bit, and we have to pad the conduit more due to the nature of the spoil.”
Another challenge was getting the trencher into work areas.
“The machine is large,” he said, “and can be a handful on narrower roads. We have also had to load it back onto a truck and transport it between locations to avoid traversing asphalt. It’s heavy and has metal tracks, so it’s not suitable for asphalt.
“We installed rolled HDPE conduit and are pulling cable into the conduit.”
Established in 2002, Essential Utilities is based in Santa Fe, N.M. Pilnock describes the company as a heavy electrical contractor that does trenching for dry utilities and installs electrical equipment, conduit and other utilities in trenches the company digs.
It also has a Ditch Witch JT920 directional drill to make road crossings. The drill is used for subcontract work for other trenching companies.
“We do not currently own any trenching equipment, but rent as needed,” said Pilnock. “The trenching for the Public Service of New Mexico project was rented from Ditch Witch of New Mexico, in Albuquerque.”
The project is scheduled to be completed in August 2022.
“Our people are definitely the key to our success,” Pilnock concluded. “Their skills and flexibility allow us to tackle many different challenges in the field.” •
FOR MORE INFORMATION:
Essential Utilities, (505) 473-5603
Trencor, (419) 869-7107, trencor.com
Ditch Witch, (800) 654-6481, ditchwitch.com
Comments