Rock Boring

Rock Boring

Rock boring is a trenchless technique to install steel casing that uses the same means and methods of auger boring, however, the cutter head and tooling is purpose built for rock applications. The cutter heads are outfitted with roller disc cutters that penetrate the rock creating microfractures between the disc cutter paths. Thrust is provided by the auger bore machine. As the disc cutter head advances, the rock fractures and creates chips. Scoops on the cutter head periphery transition the material into the auger string for removal. The stabilizer pads or shoes located on the outside of the rock boring unit maintain a concentric cutter path and make minor steering corrections along the alignment.

Rock boring is commonly used in crossings up to 300‐ft. with steel casing diameters common in the pipeline utility industry. Tooling capabilities vary based on the cutter head design and installation diameter; however, 15,000 psi are achievable.

To serve the increasing demands for rock boring, Akkerman carries an extensive inventory of Rock Boring Units (RBU) ranging from 24‐in to 48‐in that are available for sale or lease.

To learn more about our equipment and how it can help you on your next project, navigate to the equipment section of our website or contact one of our sales representatives for more information.

Case Studies

GBM Case Study – Rock Boring 2

Southern Star Central Gas Pipeline, Inc., a Midwest transporter of natural gas, embarked on the $94.6M Kansas Modernization Project to improve its infrastructure’s safety and reliability.
Part of this larger initiative, Project C-60266, called for a new 36-in. natural gas pipeline between Anderson and Franklin Counties in Kansas.
Minnesota Limited of Big Lake, MN, was the general contractor responsible for 30-miles of opencut gas pipelines between the two large compressor stations.
Along the pipeline stretch, 30 trenchless crossings with an average length of 120-ft. were to be constructed by the HDD method and awarded to The HDD Company. A handful of the longer rock crossings would be completed using the auger-boring method.
As excavations were opened up, the ground conditions were notably different which changed the project scope to nearly all rock crossings.
The HDD Company enlisted support from their sister-company, The Tunneling Company (TTC) USA, LLC of Yelm WA.

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