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PAM <br />Standpipe -type piezometers, consisting of 1-1/2" Schedule 40 PVC with flush - <br />joint screw threaded couplings, were installed in each boring. The annulus <br />around each standpipe was filled with sand, and the piezometers were sealed <br />above the monitoring zone with bentonite. Piezometer sensitivity tests were <br />performed by evacuating the standpipes of water and measuring the rate of <br />water rise back into the piezometer. This was performed both to determine <br />proper functioning of the piezometers and to obtain a measure of permeabi- <br />lity. Evacuation was accomplished by compressed air introduced at the bottom <br />of the standpipe through a flexible hose, forcing the water out the open end <br />at the top. All of piezometers appeared to be functioning properly after <br />installation. ' <br />On September 8 and 9, 1982, several weeks after all construction. activities <br />were completed at the dam, the piezometers were again evacuated. inert <br />nitrogen gas was used in lieu of compressed air to avoid changes in water <br />quality. Recovery rates were monitored. The other piezometers in the <br />vicinity of the dam were evacuated and recovery rates monitored at the same <br />time. <br />Water quality samples were obtained from the piezometers on several dates <br />following piezometer installation, as discussed in Section 3.3 of this <br />report. This sampling and water quality testing was performed by Homestake <br />personnel. Water quality and water level data were forwarded to D'Appolonia <br />for review. <br />