Snelson Works To Complete Facilities Installation For Gas Storage Project

July 2010 Vol. 237 No. 7

David Dixon, Snelson Companies Inc., Sedro Woolley, WA

Snelson Companies, Inc. was contracted to construct compressor station facilities, a 26.8-mile, 30-inch gas transmission pipeline, a gathering line and related items in connection with the development of a natural gas underground storage facility located in Madera County, CA known as the Gill Ranch Storage Project.

Madera County is situated in the heart of California and is rich in agriculture with a variety of crops. Consistent with the agricultural economy the project had to cross under the California Aqueduct and numerous smaller canals conveying water from the Sierra Nevada Mountains and the valleys to the North.
One of the challenges has been installing the pipeline under the rivers, canals and highways. In addition to the four directional drills in progress by Southeast Directional Drilling, Snelson’s own crews are installing seven auger bores with varying lengths from 90 linear feet (lf) in length to 280 lf in length. The crew uses an American Augers Model 48/54-900NG track mounted horizontal earth boring machine producing up to 136,551 foot/pounds of torque and 900,000 pounds of thrust.

United Rentals Trench Safety of Fresno, CA is providing a slide rail shoring system to fit the needs for a 41 lf clear span bore pit to enable dropping into the pit maximum lengths of casing pipe. They are meeting our needs with a site specific engineered system designed by a licensed engineering firm. On site assembly assistance as needed is provided by United Rentals personnel as well.

The shoring system weighs 183,000 pounds and gives Snelson a bore pit 60-feet-long by 12-feet-wide by 20-foot-deep to install the deep bores that go under irrigation canals. The slide rail is a modular, dig and push-shoring system that proved ideal for this application.

The accompanying photos show the bore pit and crews hooking up the interconnect fabrication that ties the 30-inch line into the PG&E station.

Construction was proceeding quickly toward a July 31 pipeline construction completion and an overall project completion in the fall.