Auger boring has been a staple installation method for underground construction contractors for decades, providing a means for contractors to install pipe reliably and with limited surface disruption. The method traces its roots to the 1930s where it was used to excavate coal seams in West Virginia.
The process of auger boring involves excavating the face of the tunnel, using flighted augers to carry the spoil back to the launch pit, while simultaneously jacking in casing pipe to support the excavation. Typically, auger boring is used for installing pipes under railways or roads where settlement or upheaval is a concern. Auger boring can used for projects up to about 60 in. and more, and lengths of up to about 600 ft.
As auger boring nears its centennial anniversary, equipment manufacturing pioneer American Augers of West Salem, Ohio, has introduced an innovative new approach to the time-tested technology – an electric auger boring system. The 36/42-600E auger boring machine uses an electric motor to produce 600,000 lbs of thrust coupled with remote-controlled operation, providing contractors with an alternative to traditional diesel-powered systems.
“The electric driven auger boring unit began because the construction industry is moving to powering equipment differently,” said Richard Levings, American Augers product manager. “The global environmental push to reduce emissions has forced many manufacturers to look at different technology to power equipment. Auger boring machines were a logical place for us to start that development.”
Levings says that the electric drive offers multiple advantages when applied to auger boring machines. “First and foremost is the elimination of diesel exhaust in the boring pit,” he said. “Additionally, the system can be remotely operated to allow the operator freedom of movement for visibility through all operations. Electric power transfer offers a wider and flatter power curve so torque can be allied along a wider range of speeds; controllability is enhanced over mechanical drives; and noise is greatly reduced vs. diesel engine drives.”
While electric and diesel-powered auger boring systems operate on the same principles, there is an adjustment period for the operator.
“Controlling the unit remotely is a big change for long-time operators who have always run the units standing on the side of the mainframe,” Levings said. “Disconnecting from that while it seems simple and logical, is different and change often comes with hesitancy. The electric unit is extremely responsive vs. the conventional unit. This does take some time to adjust for long-time operators but once they learn to harness that responsiveness, it becomes very useful.”
The Tunneling Company in Canada (formerly Kamloops Augering & Boring Ltd.), recently completed unique bores as part of a project to bring fiber optics to Inuvik in the Northwest Territories. One portion of the project required The Tunneling Company to install casing at a steep 26-degree angle in -40 F temperatures.
The Tunneling Company installed the 24-in. starter casing through permafrost and gravel to allow directional drilling to begin in more optimal ground conditions. “We were concerned whether a conventional diesel-driven boring system would work at that extreme angle,” said Shawn Gaunt, president of The Tunneling Company. “The electric auger boring system worked very well. American Augers also had support personnel on site to make sure the equipment functioned in those extreme conditions.”
Gaunt agreed that the electric system took some getting used to. “One of the biggest differences was in operating the machine. Because it is silent, you need to pay attention to the gauge to make sure it is not being overloaded. With a conventional machine, you can hear the difference as the machine starts to load up.”
The Tunneling Company used the 36/42-600E to complete three bores in the range of 100 m long with depths to 50 m.
Michels used the electric auger boring system as part of a natural gas pipeline project in British Columbia. The system was used to successfully complete a series of 36- to 48-in. pipe installations 3 to 4 m deep in glacial till, according to Greg Flaman. “The system was easy to adjust to and we immediately liked the fact that with the remote control you don’t have to stand on the machine. The setup is virtually the same compared to a diesel system except for the electric system is a little lighter and you have the main power cable running into the pit.”
So, with electric and diesel systems both viable options, what should a contractor consider when selecting auger boring equipment?
Said Levings: “There are several factors to consider: Noise restrictions, environmental regulations (emissions-free), temperature (electric drives can operate in more extreme temperatures) and depth (deep pits have requirements diesel units struggle to meet. Given these advantages, the electric system gives a contractor the ability to meet a broader range of bid requirements.”