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Whetstpne` <br />d CCOSO- -2AaC Technical Memorandum <br />To: Ben Vallerine (Black Range Minerals) 4153A <br />From: Susan Wyman, P.E., P.G., and Scott Effner, P.G. (Whetstone Associates) <br />Date: April 22, 2011 <br />Subject: Equipment Specification and Methodology for the BRMC Hydrogeology Study <br />This memorandum provides standard operating procedures (SOPS) and equipment specifications for the <br />installation of vibrating wire piezometers (VWPs) at the Taylor Ranch South T Bar (STB) Project. The <br />VWPs will be installed in a minimum of four HQ-diameter mineral exploration core holes. The core holes <br />will be drilled in bedrock and will range in depth from approximately 645 to 820 feet at the Hansen Deposit <br />and from 100 feet to 260 feet at the Picnic Tree deposit. <br />Durham Geoslope (aka Slope Indicator) VWPs will be used for the installations and will be provided by <br />Whetstone. The VWP converts water pressure to a frequency signal via a diaphragm, a tensioned steel wire, <br />and an electromagnetic coil. The signal is transmitted to the readout device at the surface. The standard <br />Slope Indicator VWPs (Figure 1) will be attached to schedule 80 PVC pipe and directly grouted-in using a <br />bentonite-cement grout. A Quattro logger will be installed at the surface for each instrumented core hole. <br />Figure 1. Slope Indicator Vibrating Wire Piezometers <br />1.1 VWP Installation Procedures <br />The VWPs will be attached to a 1.5-inch diameter sacrificial grout pipe and will be lowered into place using <br />the drilling rig. The pipe controls the elevation and relative spacing of the piezometers, and is used for <br />placement of grout. Adequate pipe must be furnished to grout from 20 feet off the bottom of the hole. Flush <br />jointed or threaded and coupled sacrificial grout pipe may be used for the VWP installation provided that the <br />thread strength is adequate to support the entire assembly suspended in tension. The installation procedure is <br />as follows: <br />1. Install the VWPs after packer testing is completed, and the hole is clean. <br />2. Prepare the piezometer: Submerse the piezometer in a bucket of clean water, pull off the filter to <br />allow air to escape from the piezometer, then replace the filter. Hold the piezometer with filter end up <br />to prevent water from draining out. <br />4153A.110422