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Homestake 2009 Geotechnical Observations <br />Pitch Reclamation Project Indian Creek and Tie Camp Creek Waste Rock Dumps <br />few years were from a small interval of water perched on the silt in- filling, and because of <br />the blockage in the standpipe, not necessarily indicative of water levels in the underdrain. <br />In 2009, water levels in this piezometer averaged 184.1 feet bgs, down from 183.9 feet bgs <br />in 2008. The maximum differential in 2009 was 8.2 feet, down from 15.5 feet in 2008 and <br />more within the differential range noted historically. <br />In the fall of 2009, piezometer 10300 was also flushed with pressurized water in an attempt <br />to wash out some of the silt built up in the casing. The 10300 piezometer washed out fairly <br />well although it isn't as deep as it was historically, but the readings appear to be more in line <br />with the historical reading in this piezometer. <br />The 10300 piezometer will continue to be evaluated during the 2010 field season. An <br />attempt will be made to continue to clear the silt by flushing the casing with high pressure <br />water. In the event that flushing does not restore the functionality of the piezometer, we will <br />evaluate the purpose and need of the piezometer and decide if replacement is critical to <br />long -term monitoring of the Indian Creek Waste Rock Dump. <br />2. Tie Camp Waste Rock Dump <br />a) "10400 - 10100" Level <br />Sit Description The Tie Camp Waste Rock Dump was regraded in 1994 following <br />procedures approved in the February 1994 Technical Revision. During 1995, minor, <br />localized areas of slope instability were noted, corrected, and reported in the 1995 Annual <br />Geotechnical Report. <br />20 Observations Piezometer TC10375 monitors the Tie Camp Creek Waste Rock Dump. <br />In 2009, water levels averaged 169.5 feet bgs, with a maximum observed seasonal <br />fluctuation of 6.1 feet in late May. The maximum fluctuation was the down from the 2008 <br />maximum fluctuation of 12.3 feet and more in line with historical readings and is deemed as <br />an acceptable seasonal variation. The increase in the water level in the May -June period <br />was likely related to the heavy snow pack in 2008 and 2009. Field observations indicate <br />that the repairs performed in 1995 were successful and no new areas of surficial instability <br />were observed from 1996 through 2009. In 2010, we will continue to monitor closely the <br />surface conditions of the Tie Camp dump after the spring snow melt. <br />3. Piezometers — 2009 General Comments <br />The 2009 water level measurements showed a maximum differential following snow melt more <br />in line with historical readings. Following the dry conditions of 2001 through 2003, the seasonal <br />variations have increased in recent years as heavier snow packs have occurred. We believe the <br />increases in the maximum water levels are related to the spring snow melt and the saturated <br />zone within the dumps remains relatively thin and free draining. Homestake will continue to <br />evaluate the conditions of the piezometers and remedy the buildup of silt in the casings, as <br />possible. We will continue to monitor and evaluate the effects of the seasonal spikes in the <br />piezometric water levels, and also observe any changes in surface features of the dumps. <br />There continues to be no indication of any concern related to instability in either of the waste <br />rock dumps. <br />Homestake Pitch Reclamation Project Page 3 <br />2009 Annual Geotechnical Report December 15, 2009 <br />M- 1977 -004HR 2009AnnualGeotechnicalReportText _Final.doc <br />