Frenchman’s Coulee Crossing

Coleman Construction recently completed its longest and deepest crossing to date by finishing the drive for the Frenchman’s Coulee Crossing in Belt, Montana. With a total drive length of 732’ and a maximum depth of over 177’ it’s the deepest and longest pipe jacking ever completed in the state of Montana.

With challenging ground conditions being of old fill imported from the surrounding area the potential for large boulders was likely. Coleman Construction opted to design and build its own digger shield TBM to handle such obstructions. The digger shield was designed and built in Dillon Montana and was promptly named “Chew-Rokka” before starting its voyage under Highway 89. During construction of the tunnel many manmade objects were encountered including steel cable, galvanized pipe and reinforced concrete. Other objects were encountered including sandstone boulders measuring over 8’ across its largest diameter. Chew-Rokka was able to maneuver quickly thru these obstructions with out delay and no change of conditions was requested from the owner for the entire drive due to these obstructions.

The steel casing drive was completed on October 19, 2022 and set the stage for follow up work to be completed. This includes recovering the steel casing using Reinforced Concrete Pipe as the two-pass liner to drive the steel casing out to use on future crossings.

Completion of the main drive was a key milestone for showing that Coleman Construction can take on some of the most challenging pipe jacking projects in Montana, Wyoming, and Colorado. Final completion of this project is expected at the end of November 2022.