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o High grout takes in the weathered rock. <br />Lost Circulation and Grout Takes in Dam <br />The loss of circulation zones and zones with grout takes greater than 5 <br />cubic feet of grout per foot of boring are shown in Figure 3. Detailed <br />grout take quantities are presented in the construction report (D <br />polonia, 1983). Loss of circulation in the dam fill occurred in grout <br />borings C-3, G-5, G-6, G-7, and G -S. Large grout takes in the dam fill <br />occurred in grout borings G-4, G-7, and G-8. The grout take nG-4ores <br />over a 38 foot long zone including the alluvial soil layer, <br />the actual grout take may have been entirely in the alluvial layer. <br />A dye test was conducted in grout boring 10-7 between depths of 62 to 66 <br />feet. Dye was observed in the tailings pond immediately upstream from <br />G-7 after injection of 350 gallons of dye. <br />The causes of circulation losses, high grout takes, and communication <br />between the dam core and tailings pond required an explanation <br />can order <br />to properly evaluate the embankment integrity• <br />Possiblemechanisms for the occurrences noted during the grouting were: <br />o Hydraulic fracturing f the fill <br />terial from <br />drilling fluid or gr <br />boreholes. <br />o -Cracks in the fill material. <br />o Pervious zones-in..the.fill material. <br />The occurrence of circulation losses in borings in dam fills is discus- <br />sed by 5herard, 1973. Circulation losses can occur when drilling with <br />fluids in an embankment dam and the embankment can still perform <br />acceptably- if the cause is related to the first item listed bove the <br />embankment may be sound and the observations are not of great <br />Hydraulic pressure in the borehole or grout can exert high horizontal <br />pressures. Since zones within a dam can exist with low horizontal <br />tea- �r-v�A)lO � <br />