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Homestake 2008 Geotechnical Observations <br />Pitch Reclamation Project Indian Creek and Tie Camp Creek Waste Rock Dumps <br />e) "10600-10400" Level <br />Site Description: Identical to that of past reports for 1996 through 2007. <br />2008 Observations: Piezometer IC10440 was located in this area; however, it was lost in <br />September 1996. Piezometer IC10525 can also be considered to be within the area. The <br />2008 data for that piezometer is described in the previous section. <br />f) "10400 - 10370" Level <br />Site Description: Identical to that of past.reports for 1996 through 2007 <br />2008 Observations: The 2008 field observations are similar to those reported in past <br />reports. Piezometer IC10360 is located in this area. Water levels in this piezometer <br />averaged about 223.4 feet bgs, with a seasonal fluctuation of approximately 8.6 feet. <br />Despite a record snow pack in 2008, this represented the smallest rise. in the piezometric <br />surface data since 2002. The total depth of this piezometer is 260 feet and the thickness of <br />the dump is approximately 240 feet. <br />During the winter of 2007, wildlife knocked off the casing of Piezometer IC10370 and kicked <br />debris into the 2 inch pipe. This piezometer has never shown seasonal water levels <br />fluctuations greater than one foot, with the averaged water level of 190.7 feet bgs. The <br />bottom of this piezometer is 192 feet bgs. We were not able to repair the piezometer in <br />2008, but will attempt to remove the material in the piezometer in 2009, and if successful, <br />monitoring will be resumed at this location. <br />During 1997, Homestake reconstructed the face of the permanent low-grade stockpile <br />located on the Indian Creek Waste Rock Dump. The purpose of the slope reconstruction <br />was to reduce the potential for infiltration and promote more rapid runoff from the slope. No <br />seepage was observed in this area in 2008. <br />g) "10300 - 10100" Level <br />Site Description: The Indian Creek Waste Rock Dump was regraded in 1994 following <br />procedures approved in the February 1994 Technical Revision. During 1995, several minor, <br />localized areas of slope instability were noted, corrected, and reported in the 1995 Annual <br />Geotechnical Report. <br />2008 Observations: Field observations indicate that the repairs performed in 1995 were <br />successful and no new areas of surficial instability (slips) were observed from 1996 through <br />2008. Piezometer IC10300 is located in this area. In 2008, water levels in this piezometer <br />averaged 188.5 feet bgs, however, there was a maximum seasonal fluctuation of 15.3 feet <br />in late May and the piezometer has not yet returned to its normal level of approximately 190 <br />ft. bgs. <br />Field records indicate that the 10300 Piezometer was originally drilled to a total depth of 210 <br />ft. The final depth of the installation was not recorded in the field record at that time. <br />Inspection of the 10300 Piezometer on November 24,2008, indicated that the bottom of the <br />standpipe has become filled with soil (silted-in) to a depth of about 180 ft. bgs, as indicated <br />by sounding the total depth of the standpipe. A steel surge block was lowered into the <br />standpipe, and rather than encountering a blockage, the surge block became partially <br />submerged in the slurry-like material, which was present on the block as observed when it <br />was returned to the surface. <br />Homestake Pitch Reclamation Project Page 2 <br />2008 Annual Geotechnical Report December 15, 2008 <br />M-1977-004H R 2008AnnualGeotechnical ReportText_Final.doc <br />