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Geotechnical Engineering Report lrerracon <br /> Carr Aggregate Pit ■ Carr, Colorado <br /> April 23, 2020 ■ Terracon Project No. 20195087 GeORepOrt. <br /> EXPLORATION AND TESTING PROCEDURES <br /> Field Exploration <br /> The field exploration program consisted of the following: <br /> Number of Exploration Boring Depth (feet) Location <br /> Points <br /> 5 Borings 19'/z to 25'h <br /> - See Exploration Plan <br /> 22 Test Pits 81/to 14'/z <br /> Boring Layout and Elevations: We used handheld GPS equipment to locate borings with an <br /> estimated horizontal accuracy of +/-20 feet; test pits were located by Kiewit. A ground surface <br /> elevation at each boring location was interpolated by Terracon from test pit elevations provided <br /> by Kiewit. <br /> Subsurface Exploration Procedures: We advanced soil borings with a truck-mounted drill rig <br /> using continuous-flight, hollow-stem augers. Three samples were obtained in the upper 10 feet of <br /> each boring and at intervals of 5 feet thereafter. Soil sampling was performed using ring-lined <br /> split-barrel or standard split-barrel sampling procedures. For the standard split-barrel sampling <br /> procedure, a standard 2-inch outer diameter split-barrel sampling spoon is driven into the ground <br /> by a 140-pound automatic hammer falling a distance of 30 inches. The number of blows required <br /> to advance the sampling spoon the last 12 inches of a normal 18-inch penetration is recorded as <br /> the Standard Penetration Test (SPT) resistance value. The SPT resistance values, also referred <br /> to as N-values, are indicated on the boring logs at the test depths. For ring-lined split-barrel <br /> sampling procedure, a 3-inch outer diameter split-barrel sampling spoon is used for sampling. <br /> Ring-lined split-barrel sampling procedures are similar to standard split-barrel sampling <br /> procedures; however, blow counts are typically recorded for 6-inch intervals for a total of 12 inches <br /> of penetration. The samples were placed in appropriate containers, taken to our soil laboratory for <br /> testing, and classified by a geotechnical engineer. In addition, we observed and recorded <br /> groundwater levels during drilling observations. <br /> Test pits were excavated using a Caterpillar 336 excavator operated by Kiewit. Overburden soils <br /> were segregated and spoiled adjacent to the excavation. Upon encountering soils containing <br /> aggregate materials, materials were spoiled on the opposite side of the excavation. Aggregate <br /> materials were placed on the surface in linear fashion; depth intervals or material changes were <br /> placed in essentially a straight line to facilitate sampling. Stockpiles were sampled in general <br /> accordance with ASTM C702. Upon completion, materials were placed in the excavation and <br /> covered with overburden soils at the surface. <br /> Responsive■ Resourceful ■ Reliable EXPLORATION AND TESTING PROCEDURES 1 of 2 <br />