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• Blue Ribbon Mine - AHR Pa e 2 <br />GROUND WATER <br />Piezometers <br />The piezometers on the mine bench were monitored quarterly for water level. Graphs <br />are included with this report which show historical water levels of the piezometers. <br />The water level in P-1 peaked in June and then the water level dropped 10.3 feet to <br />18.1 feet in December. <br />Piezometer P-2 showed a peak water level in June and then by December it dropped <br />14.5 feet to a level consistent with prior years records for this piezometer. <br />Piezometer P-3 showed a peak water level in March and then by December it dropped <br />15.1 feet to a level consistent with prior years records for this piezometer. <br />The piezometer at the top of the bench, P-4, showed little variation during the year. <br />The water level in P-5 averaged 17.7 feet deep during the year. At the end of the year <br />the water level in P-5 was 16.0 feet deep. <br />Monitoring of piezometer P-6 has been discontinued because it was destroyed by the <br />1993 bench cover material slump. <br />Underdrains <br />The north, middle and south underdrains were dry the entire year. The flow and mass <br />average conductivity of the underdrains for the last ten years is summarized in the table <br />below. Flow is presented in acre-feet. Conductivity is measured in umhos/cm. <br />The fact the underdrains are dry could be a concern except the piezometers also show <br />a trend toward lower water levels. With the lower water levels in the piezometers, one <br />would expect the flow in the underdrains to be lower or dry. <br />