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-3- <br />partially backfilled with soil. The profile is presented on Table land the information is <br />from; (1) our field observations, (2) the National Resources Conservation Service (2013) <br />and (3) information from the assistant ranch manager, Brett Davidson. At the existing <br />borrow pit the representative soil profile is about 1.5 feet of loess overburden over about <br />8.5 feet of gravel in a loamy sand to sand soil matrix (River Alluvium Unit Qa1) that <br />overlies about 10 feet of gravel, cobbles and boulders in a loamy sand to sand soil matrix <br />(River Alluvium Unit Qa2). In the existing borrow pit, Mr. Davidson reports that the <br />Pierre Shale (Geologic Unit Kp) lies at a depth of about 20 feet below the high -level <br />terrace surface. Perched groundwater was also reported by the assistant ranch manager to <br />be present at the shale /river alluvium contact before the pit was backfilled. <br />SUBSURFACE EXPLORATION <br />The subsurface exploration was performed on August 29, 2014. Seven exploratory pits <br />were excavated in the southern one -half of the potential new borrow site at the <br />approximate locations shown on Figures 2 and 3. The pits were excavated with a John <br />Deere B310 SJ backhoe supplied by the Blue Valley Ranch. The pits were logged by a <br />representative of Hepworth- Pawlak Geotechnical. Disturbed bulk samples of the subsoil <br />were taken from the pits at the depths shown on the pit logs, see Figure 4. The samples <br />were returned to our laboratory for review by the project engineer and testing. <br />SUBSURFACE CONDITIONS <br />Graphic logs of the soil profiles observed in the exploratory pits are shown on Figure 4. <br />The general soil profile below the high -level terrace surface at the potential new borrow <br />site evaluated is; (1) an overburden loess over, (2) a river gravel deposit over, (3) shale. <br />At the pit sites the overburden loess is thin and was from 0.5 to 5.0 feet thick. The <br />overburden loess is a clay loam with an A/Bt/Bk pedogenetic soil profile. The thickness <br />of the gravel deposit in the three pits that encountered shale was between 6.0 to 14.5 feet. <br />In the four pits that did not reach shale the gravel deposit was greater than 8.0 feet to <br />greater than 13.0 feet thick. Most of the gravel deposit in the seven pits consisted of <br />gravel, cobbles and boulders in a loamy sand to sand matrix and is similar to River <br />Job No. 114 342A p��h <br />