Department of the Interior, U.S. Geological Survey, 345 Middlefield Road,Mail Stop 285, Menlo Park, CA 94025-3591

N -- DRILLING SERVICES FOR INSTALLATION OF MONITORING WELLS SOL IFB 98WRSS1006 DUE 071598 POC Rita A. Leach, MS-285, (650) 329-4162 E-MAIL: Click here to contact the contracting officer via e-mail., Rita A. Leach, MS-285, (650) 329-4162. The U.S. Geological Survey has a requirement for drilling a test hole and installation of monitoring wells near Fallon, Nevada in Churchill County. The purpose of the test hole and wells is to obtain geologic, water level, and water chemistry data at different depths in and near the Fallon basalt aquifer. The upper portion of the hole shall be drilled through approximately 400 feet of basin-fill sediments (gravel, sand, silt and clay) overlying the basalt aquifer. The thickness of basalt aquifer to be drilled is described by three alternative test hole and well designs. A single alternative will be selected. For each Alternative, the upper portion of the test hole shall be drilled to about 400 feet in depth to the top of the basalt and permanent steel casing installed and cement-grouted above the basalt aquifer. The lower portion of the test hole shall be drilled with dual-wall drill stem and reverse circulation, using air and air percussion bit to allow drilling a small diameter(6") test hole to a depth of 1,000 feet below land surface and installation of a single monitoring well in the test hole, Alternative B consists of drilling a large diameter (8") test hole to a depth of 1,000 feet below land surface and installation of two monitoring wells in the test hole, and Alternative C consists of drilling a larger diameter (10") test hole to a depth of 1,000 feet and installation of three monitoring wells. Water samples and basalt cores shall be obtained at specified depths within the basalt. Drilling is expected to start in early October 1998 and shall be completed 90 days after notice to proceed. A site visit is scheduled for 10:00 a.m., Tuesday, June 30, 1998. All parties interested in attending the site visit should call the contracting officer by close of business on Monday, June 29, 1998. (0147)

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