May 11, 2016 Great Southwestern Construction Minimizes Environmental Impacts During T-Line Construction
USE OF WALKING EXCAVATOR, SKY CRANE HELPED PREVENT DAMAGE TO DELICATE AREAS ON ANTELOPE VALLEY TO JUDSON PROJECT
MYR Group subsidiary Great Southwestern Construction, Inc. has successfully finished construction of the 144-mile Antelope Valley Station to Judson transmission line for Basin Electric Power Cooperative (Basin Electric) in North Dakota.
The two-year project was designed to expand and upgrade the transmission system in the Bakken Formation, an area covering approximately 200,000 square miles that is rich with opportunity for oil and gas exploration and production. The 345kV, single circuit line consists of direct embed monopole, 3-pole and H-frame structures, and begins in Beulah, ND, and runs west toward Grassy Butte then north to Williston. The line ties into the newly constructed Judson substation, which was also built by Great Southwestern Construction.
Crossings over the Big Missouri and Little Missouri Rivers, along with state and federal lands, required close coordination with many entities, including Basin Electric, the U.S Forest Service, the Army Corps of Engineers, the Western Area Power Administration (WAPA), and the United States Department of Agriculture’s (USDA) Rural Utilities Service (RUS).
In addition to sub-zero conditions, crews grappled with unseasonably warm temperatures.
“We encountered warm patches during the winter months that thawed the ground which required more matting and made it more difficult to deliver material and maneuver equipment in the muddy, rugged countryside,” said Great Southwestern Construction Project Manager Phil Powell.
One particular portion of the project that presented some unique environmental and construction challenges was located on the north side of the Little Missouri River in the Badlands.
Plans called for several H-frame structures to be constructed in some rugged terrain adjacent to the Theodore Roosevelt National Park.
To minimize impacts on surrounding soil and wildlife, the team utilized a ‘Kaiser’ walking mobile excavator. The excavator looked like a large spider while it carefully climbed down a 60-degree grade and drilled 20-foot deep holes for the H-frame structures. An Erickson Sky Crane was also used to pick, fly and set the 16,000 lb. structures, which avoided the use of heavy equipment and matting that could have damaged delicate ground conditions and caused additional disruptions to wildlife inhabiting the area.
“We’ve overcome a lot of obstacles on this project such as recruitment, weather, terrain and special requirements on the ROW,” Powell said. “I’m really proud of the effort we’ve put forth here to overcome these obstacles and get the job done.”