Lower Big Haynes 54-inch Sanitary Sewer Project

Completed in 2008 by Southland Contracting, the Lower Big Haynes 54-inch Sanitary Sewer Project consisted of installing approximately 900 linear feet of 84-inch neutral axis liner plate tunnel with a 54-inch sanitary sewer project pipeline. The biggest challenge of the project was crossing a creek with mixed face material. On the bottom there was granite at strengths in strengths in excess of 35,000 psi and on the top half there was silty sands and groundwater flowing at a rate in excess of 10,000 gallons per minute. Southland Contracting, Inc. overcame this by building a shield equipped with shutters in the top half of the face and used controlled blasting to excavate the rock invert.