Boring Through A Crowd

By Jeff Griffin, Senior Editor | April 2012, Vol. 67 No. 4

Community-owned Colorado Springs Utilities (CSU) provides electric, natural gas, water and wastewater services to 645,000 residential and commercial customers in the Pikes Peak region of Colorado.

The multi-utility approach has served the area since 1924, giving customers a single source for basic services, streamlining management and operations for construction and maintenance of infrastructure, and eliminating the potential for conflicts among separate utility providers.

When CSU recently needed to upgrade the power feed to an Agilent Technologies facility, horizontal directional drilling (HDD) was selected as the method of construction for one key segment of the installation, primarily because of the large number of existing below-ground utilities in proximity to the planned route of the pipe installation, said Mason Parsaye, general manager, Energy Services Division of CSU.

csuart2.jpg

Using HDD to avoid cutting the street also saved Agilent the cost of degradation fees. The bore extended from Agilent’s property, down a 15-foot incline, leveling to cross under the high-traffic, six-lane Garden of the Gods Road.

The installation was made by one of four CSU crews headed by Bill Doyle, the CSU bore crew operations supervisor. The crews make HDD installations for CSU’s electric, gas and water operations.

Doyle said that avoiding damage to the multiple existing utilities -- in addition to the routine aspects of any directional installation -- made installing this section of pipe especially challenging.

Obviously careful planning was essential.

Delicate procedure

In addition to safely crossing existing utilities, it was important that tension applied to the pipe during its pullback through the pilot hole did not compromise the integrity of the pipe.

To monitor tension to the pipe during installation, the decision was made to use a TensiTrak monitoring system which required a DigiTrak F5 tracking system, said Doyle. LWD (log while drilling) software, used with the F5 tracker, provided an accurate as built of the installation.

Potholing to visibly verify and mark the locations of the existing utilities required two days, primarily because most of the utilities were in the middle of the street, said Josh Hardcastle, crew supervisor for the project. A McLaughlin V1200 vacuum excavation unit was used.