The Phoenix Expansion project is a 259-mile expansion of a natural gas pipeline, owned by Transwestern Pipeline Company, Houston, Texas. The expansion is designed to help supply the fast growing energy demands of customers in the Phoenix area, specifically Maricopa County.While much of the pipeline expansion route, which extends from Transwestern's mainline in Yavapai county to just south of the Phoenix area, requires standard open cut pipeline construction techniques, a large portion does utilize trenchless technology such as directional drilling, auger boring and pipe ramming.One segment in particular called for a 4003-foot HDD crossing of the Gila River west of Phoenix. The Crossing Company, Nisku, Alberta, CA, was called in to perform the high-profile bore that included the installation of a 36-inch steel pipe over 3/4 of a mile longThe Crossing Company employed a Conductor Barrel? installation. The Conductor Barrel is a patented process and differs slightly from the other HDD Assist methods in the sense that it deals with the actual drilling aspect of the project rather than pullback or recovery.The soil conditions at the Gila River crossing prompted Crossing Company crews to install the Conductor Barrel. In order to accommodate the necessary reaming for the project and ultimately the 36-inch pipe, a 147-foot, 60-inch diameter casing was used for the Conductor. To ram the casing in place, crews used a 24-inch diameter pipe rammer.The Crossing Company was able to successfully complete the crossing of the Gila River one of the only documented, if not the only, successful HDD crossing of that river.
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