New Auger Boring System Handles Large Diameter, Line & Grade Projects

November 2012, Vol. 67, No. 11

“For example,” he said, “with pilot boring systems, the bores necessary after the pilot bore are supported by the pilot drill string while the American Auger systems are supported by the full surface of the product pipe. When compared to the traditional microtunneling machines, there is a definite advantage to the retractability of the system coupled with easily-installed, less-costly kit modifications for different bore diameters. In general, the system offers greater flexibility than other equipment currently on the market.”

Regarding steering, Vidovic said other pilot boring systems operate with a LED (light-emitting diode) in the cutting head which is scoped with a theodolite through the drill pipe through a window no larger than 3.5 inches in diameter.

flaaart4.jpg

“This means if the cutting tools deflect off of center more than 1.75 inches, the position will be lost,” he added.

Guidance
The American Augers system utilizes a laser that is pit mounted and strikes a target on the cutting head. Because the American Augers system is a single-pass system, Vidovic said the target is mounted downhole on the product casing, ensuring that the pipe be placed accurately.

“The beam path is between the 24-inch diameter secondary casing and the primary casing of 48-inch or larger diameter,” Vidovic continued. “This gives a window of approximately 12 inches diameter at a minimum, allowing a better view of the actual product pipe position.

“The American Augers system employs a laser/theodolite and a camera, with the camera mounted downhole and always at a fixed distance from the target, assuring that distance is not a challenge to the system to provide accurate positioning. Bores of 800 to 1,000 feet are possible,” he explained.

For comparison, Vidovic said pilot boring systems employ a pit-mounted camera to monitor the head position.

“Because the camera is in the pit,” said Vidovic, “its ability to scope the target is challenged by distance, usually limited to the 500-foot range.”

In addition, Vidovic said that other boring equipment available using lasers are designed for smaller diameter bores than the 48GM8000, and that attempting a bore of larger diameters with such equipment is cost prohibitive.

After the laser guidance system, Vidovic said the other feature to emphasize is the 48GM8000’s retractability.