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Homestake 2011 Geotechnical Observations <br />Pitch Reclamation Project Indian Creek and Tie Camp Creek Waste Rock Dumps <br />bentonite. The wellhead was completed with concrete and 8 inch steel protective <br />casing and concrete apron <br />The new piezometers were developed in September by purging with a combination of 3- <br />inch diameter by 36 -inch poly - bailers and a Grunfos 2 -inch Redi -Flow® impeller pump. <br />Prior to, and between purging and pumping, piezometers were surged with a 1 -inch <br />diameter by 24 -inch PVC slug and a 3 -inch by 24 -inch PVC Slug. The entire screen <br />length of both piezometers was surged with slugs prior to purging. Wells were then bailed <br />by hand until water cleared. Additional casing volumes were then removed with the <br />impeller pump and field parameters were recorded in five minute intervals until <br />parameters had stabilized. <br />The total volume of water removed from 1010300R was approximately 100 gallons, or <br />a total of 5 well casing volumes. A slug and bailer were used to extract approximately <br />25 gallons of turbid water. The well began to clear after 25 gallons and an impeller <br />pump was used to produce approximately 75 gallons of water (or approximately 4.5 <br />well casing volumes). The pumping rate during development of 1010300R was <br />approximately one gallon per minute (gpm). The piezometer quickly recovered to static <br />water level after development and is now measured monthly. <br />The total volume of water removed from 1010370R was approximately 105 gallons, or <br />a total of approximately 10 well casing volumes. A slug and bailer were used to extract <br />approximately 25 gallons of turbid water. The well began to clear after 25 gallons and <br />an impeller pump was used to produce the rest of the total volume. The pumping rate <br />during development of 1010370R was approximately 1 gallon per minute (gpm). The <br />piezometer quickly recovered to static water level after development and is now <br />measured monthly. <br />2. Tie Camp Waste Rock Dump <br />a) "10400 - 10100" Level <br />Site 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 <br />Annual Geotechnical Report. <br />2011 Observations: Piezometer TC10375 monitors the Tie Camp Creek Waste Rock <br />Dump. In 2011, water levels averaged 168.1 feet bgs, with a maximum observed <br />seasonal fluctuation of 1.83 feet between May and June. The maximum fluctuation was <br />down from the 2008 maximum fluctuation of 12.3 feet and 6.1 feet in 2009. This is <br />deemed a normal and acceptable seasonal variation. Field observations indicate that the <br />repairs performed in 1995 were successful and no new areas of surficial instability were <br />observed from 1996 through 2011. In 2012, we will continue to monitor the surface <br />conditions of the Tie Camp dump after the spring snow melt. <br />3. Piezometers — 2011 General Comments <br />The 2011 water level measurements showed a maximum differential following snow melt <br />in line with historical readings. Following the dry conditions of 2001 through 2003, the <br />seasonal variations have increased in recent years as heavier snow packs have <br />Homestake Pitch Reclamation Project <br />2011 Annual Geotechnical Report <br />M- 1977 -004HR <br />Page 4 <br />December 19, 2011 <br />2011 AnnualGeotechnicalReportText _Final.doc <br />