Laserfiche WebLink
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 7.4 feet to 23.4 feet in December. <br />Piezometer P-2 showed a peak water level in March and then by December it dropped <br />19.8 feet to a level consistent with prior years records for this piezometer. <br />Piezometer P-3 did not peak in March. It was at a low level (+50') the entire year. <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 17.9 feet deep during the year. At the end of the year <br />the water level in P-5 was 19.6 feet deep which is relatively low for this piezometer. <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 />• <br />