Exploration no. 146328 is a Geotechnical (depth 234 feet) named: TH-3 described in subsurface document no. 64117. The document, a report titled Additional Information For 2007 Part 12D Inspection Report South Fork Tolt River Project, FERC No. 2959 King County, WA was prepared by City of Seattle, Public Utilities, Geotechnical Engineering on 10-01-2010 for a Utility project.