2009-12-22_REPORT - M1977004 - Laserfiche WebLink

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Homestake Pitch Reclamation Project 2009 Geotechnica/ Observations Indian Creek and Tie Camp Creek Waste Rock Dumps 1. Indian Creek Waste Rock Dump a) "10800" Level Si Description Identical to that of past reports for 1996 through 2008. 2009 Observations The 2009 observations are similar to those reported for this area during the past thirteen years. Visual inspection of the area has revealed no evidence of settling or slumping of the rock dump material in 2009. Drainage channels are functioning as designed. b) "10780-10650" Level S ite Description Identical to that of past reports for 1996 through 2008. 2 009 Observations The 2009 observations are similar to past observations. Visual inspection of the area has revealed no evidence of settling or slumping of the dump material in 2009. Drainage channels are functioning as designed. c) "10650-10600" Level Sit Description Identical to that of past reports for 1996 through 2009. 20 Observations Unlike previous years, in 2009 there was no water detected in Piezometer IC10630. In past years, approximately a foot of water was noted in mid- to late June following the spring snow -melt before it drops back to a normal range within approximately a month. As noted in previous reports, in October 2001, an obstruction was removed from Piezometer IC10600, allowing it to be used once again for the collection of piezometrc surface data. In June of 2005 and again in 2007, a level fluctuation of nine feet was observed in this piezometer, which was the greatest fluctuation to date in water elevation since the obstruction was removed. In 2006, the water level fluctuation was small at 1.5 feet. In 2009, the water level fluctuation rose by 8.4 feet between late May and late June then dropped back to its a normal range by mid - August. In 2009, the water level average in Piezometer IC10600 was 251.3 feet below ground surface (bgs) and was consistent with the readings from previous years. This condition is similar to other piezometers in the Indian Creek dump, and is deemed as an acceptable seasonal variation. The water level increases in 2005 through 2009 were a result of heavy snow pack and wet spring conditions. d) "10725 = 10525" Level Sit Description Identical to that of past reports for 1996 through 2008. The minor overlap between this level and other bench designations reflects the original bench configuration. 2009 Observations Piezometers IC10600 and IC10525 bound this area. In 2009, the water level in Piezometer IC10525 increased by 8.6 feet in early May and June and, similar to Piezometer IC10600, dropped back to normal levels in late -July. This behavior is very similar to that of past reports for 1996 through 2008. In 2009, the average water level in