HDD Project Completed In Cascade Mountains

Extreme Boring
By Jeff Griffin, Senior Editor | May 2011, Vol. 66 No. 5

The project was finished on-time and on budget. Lachner credited successful completion of the project to careful planning preparation before work began and the experience and performance of crew members who made each installation precisely as planned.

“Each bore was different and required adjusting mud flows and pressures and other variables,” said Lachner. “A lot of things had to come together for everything to go as it did.”

The Apex project manager was Jason Stephenson and Ryan Zimmerman operated the drill unit. President Mike Lachner was actively involved in operations throughout the project.

Based in Damascus, OR, Apex works on a national level serving multiple clients. The company currently owns eight HDD units ranging in pullback from 30.000 to 100,000 pounds. Soon after completion of the Cascade project, a second 100,000-pound unit was purchased.

In retrospect, would Apex take the job again?

“Absolutely,” Lachner answered. “We love ‘impossible’ jobs.”

Six ‘Impossible’ Bores
Each of the six bores made by Apex Directional Drilling in Washington’s Cascade Mountains contained high grade changes and steep slopes, and ranged in length from 1,100 feet to 2,300 feet. One bore crossed a lake with depths at 45 feet and spanning 965 feet, then up a vertical slope of about 650 feet. The other five bores were land and canyon crossings starting from the high sides of the canyons and drilling down to a level pitch at the bottom, drilling across the canyon, and elevating to the exit point on the other side. Each bore had its own engineering issues that needed to be addressed so there was no general format that could be used for all six.

Apex president Mike Lachner describes each bore:

Bore 1 was approximately 1,700 feet going under a heavily wooded canyon. We started drilling down at a minus 36 percent grade, shot down roughly 350 feet, and leveled off to drill across the bottom of the canyon spanning another 300 feet. We started at an upward angle reaching a positive 70 percent on a 200-foot incline and steered a hard left turn to the vault location at the tower.

Bore 2, called the Bluff Bore. The length was 1,500 feet. We started on the low end of the bore and went down a steep grade of minus 45 percent for approximately 300 feet, leveled off under the canyon and back up roughly 1,050 feet to the exit at a vault location, including a grade change at 650 feet reaching a positive 80 percent grade up the side of the mountain.

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