DWR_3391241 - Laserfiche WebLink

1 2-6 o Weathered and fractured bedrock (Creede Forma- tion) 7"to 17 ,feet thick; o Relatively intact bedrock. Borehole Observations During the grouting program, several observations were made which were significant to the dam stability evaluation work. These observations are: o Loss of drilling fluid (water) in the dam while drilling the grout borings. o High grout takes within the dam. o Occurrence of dye in the tailings pond from pressure Injection within the dam in grout boring G-7. o High grout takes in the alluvial soils downstream from the cutoff. o rEdidence,�oN grout, akes��- yn ppensavor. ravels s �� :. ', g ,.v r-1 �1thealiivial�soils downstream` `from t}ieacutoff:k`° I I Packer Test Results Packer testing was conducted in grout holes prior to grouting. The results of the packer testing are shown in Figure 3 as the calculated coefficient of permeability (k) over the packer interval. The coeffi- cient of permeability varied from 80 to less than 0.1 x 10-5 centimeters per second (cm/sec). Approximate average values for each foundation layer are: ' o Alluvial Soils - k = 50 x 10-5 cm/sec (only one test performed). o Weathered and Fractured Bedrock - k - 40 x 10-5 cm/sec. o Relatively Intact Bedrock - k = 0.4 x 10-5 cm/sec. Borehole Observations During the grouting program, several observations were made which were significant to the dam stability evaluation work. These observations are: o Loss of drilling fluid (water) in the dam while drilling the grout borings. o High grout takes within the dam. o Occurrence of dye in the tailings pond from pressure Injection within the dam in grout boring G-7. o High grout takes in the alluvial soils downstream from the cutoff. o rEdidence,�oN grout, akes��- yn ppensavor. ravels s �� :. ', g ,.v r-1 �1thealiivial�soils downstream` `from t}ieacutoff:k`° I I