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Geotechnical Engineering Report lrerracon <br /> Carr Aggregate Pit ■ Carr, Colorado <br /> April 23, 2020 ■ Terracon Project No. 20195087 GeoReport <br /> Groundwater Conditions <br /> The boreholes and test pits were observed while drilling and excavating and shortly after completion <br /> for the presence and level of groundwater. The water levels observed in the boreholes/excavations <br /> are noted on the attached boring/test pits logs, and are summarized below: <br /> Boring Number Depth to Groundwater After Elevation of Groundwater After <br /> Drilling/Excavating,ft. Drilling/Excavating,ft. <br /> B-1 18.7 5,546.3 <br /> B-2 19.1 5,541.3 <br /> B-3 24 5,542 <br /> B-4 16.5 5,547.5 <br /> B-5 18.3 5,536.7 <br /> CW-13 10 5,538.7 <br /> These observations represent short-term groundwater conditions at the time of and shortly after <br /> the field exploration and may not be indicative of other times or at other locations. Groundwater <br /> levels can be expected to fluctuate with varying seasonal and weather conditions, and other <br /> factors. <br /> Groundwater level fluctuations occur due to seasonal variations in the water levels present in <br /> Lone Tree Creek, amount of rainfall, runoff and other factors not evident at the time the borings <br /> and test pits were performed. Therefore, groundwater levels during mining or at other times in <br /> the life of the project may be higher or lower than the levels indicated on the boring logs. The <br /> possibility of groundwater level fluctuations should be considered when developing the design <br /> and mining plans for the project. <br /> Fluctuations in groundwater levels can best be determined by implementation of a groundwater <br /> monitoring plan. Such a plan would include installation of groundwater piezometers, and periodic <br /> measurement of groundwater levels over a sufficient period of time. <br /> Groundwater was not observed in the remaining test pits while excavating, or for the short duration <br /> the test pits remained open. <br /> Laboratory Testing <br /> Representative soil and bedrock samples were selected for grain-size analysis and plasticity <br /> testing. Materials greater than 3-inches were segregated and sent to Kiewit's laboratory for <br /> additional testing. Samples collected between 1 and 3 inches were selected for abrasion <br /> resistance, with wearing percentages ranging from 19 to 30 percent. Grain-size analyses <br /> performed on the materials less than 3 inches, indicated gravel content ranged from about 13 to <br /> a maximum of about 61 percent; fines ranged from about 2 to 14 percent within the aggregate <br /> Responsive■ Resourceful ■ Reliable 4 <br />