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77-159 <br />Nitz, Inc. -2- May 19, 1977 <br />Mineral soils encountered in the boring were classified in <br />accordance with the Unified Classification System (ASTM <br />D2487). A copy of that chart is attached. Representative <br />samples were then returned to our laboratory for verifica- <br />tion of the field classifications by a Soils Engineer. <br />Representative samples will remain in this office for a <br />period of 60 days to be available for your examination. <br />The boring was probed immediately after its completion to <br />check for the presence of groundwater. The boring was also <br />rechecked prior to leaving the site. The absence of ground- <br />water was noted in both probings of the borings to its 20 <br />foot termination depth. <br />The percolation tests were run in 6-inch diameter holes <br />drilled to an approximate depth of 36 inches, in accordance <br />with the procedures recommended by the Minnesota Department <br />of Health (MHD) and with the procedures recommended by the <br />City of Orono. In accordance with these procedures, the <br />bottom and sides of the holes were scratched with a knife <br />blade to remove any smeared soil surfaces and to provide a <br />natural soil interface into which the water may percolate, <br />Two inches of coarse sand was then placed in the bottom of <br />the holes to prevent scouring. The holes were then carefully <br />filled with clear water to a minimum depth o: 12 inches over <br />the top of the sand layer and allowed to soak overnight with <br />the percolation tests being conducted the following day. <br />RESULTS: <br />The log of soils encountered in the boring and the water <br />level observations are shown on the attachec Log of Boring <br />sheet. <br />The soil boring and percolation tests generally encountered <br />sandy clay glacial till from the surface to the 10-foot <br />depth with the top 1 foot being considered the topsoil <br />layer. Immediately underlying the glacial till, a fine to <br />medium -grained glacial outwash sand was encountered to the <br />20-foot termination depth of the boring. <br />Results of the six initial percolation tests indicating the <br />soil absorptivities in minutes per inch (mpi) are as follows: <br />HRAun" <br />ENGINEERING TESTING <br />