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• <br />• <br />Blue Ribbon Mine - AHR Page 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 March which is typical and then during the summer the <br />water level dropped 14.6 feet to 19.6 feet in November. <br />Piezometer P-2 showed a peak water level in March (lower peak than normal) and then <br />by November it dropped 13.9 feet to a level consistent with prior years records for this <br />piezometer. <br />Piezometer P-3 showed a peak water level in March (lower peak than normal) and then <br />by November it dropped 6.3 feet to a level consistent with prior years records for this <br />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 16.8 feet deep during the year. At the end of the year <br />the water level in P-5 was 16.8 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 underdrain had significantly less flow than last year. The middle underdrain <br />did not have measurable flow this year. The south underdrain had less flow during <br />1999 than 1998. The flow and mass average conductivity of the underdrains for the <br />last nine years is summarized in the table below. Flow is presented in acre-feet. <br />Conductivity is measured in umhos/cm. <br />• <br />