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78-046 <br />B. J. Builders <br />via <br />March 3, 1978 <br />11 <br />11 <br />11 <br />11 <br />n <br />n <br />u <br />1 <br />1 <br />1 <br />1 <br />I. <br />1 <br />Mineral soils encountered in the boring were classified in <br />accordance with the Unified Soils Classification System <br />(ASTM D2487). A copy of that chart is attached. Representa- <br />tive samples were then returned to our laboratory for <br />verification of the field classifications by a Soils Engi- <br />neer. Representative samples will remain in this office for <br />a 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 on February 24. The <br />absence of groundwater was noted in both probings of the <br />boring to its 20-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 procedures recommended by the City <br />of Orono. In accordance with these procedures, the bottom <br />and sides of the holes were scratched with a knife blade to <br />remove any smeared soil sur`aces and to provide a natural <br />soil interface into which L,e water may percolate. Two <br />inches of coarse sand was then placed in the bottom of the <br />holes to prevent scouring. The holes were then carefully <br />filled with clear water to a minimum of 12 inches over the <br />top of the sand layer and allowed to soak overnight. An <br />insulating material was also placed over the holes to prevent <br />freezing. The percolation tests were then conducted the <br />following day. <br />RESULTS: <br />The log of soils encountered in the boring and the water <br />level observations are shown on the attached Log of Boring <br />sheet. <br />The soil borings and percolation tests generally encountered <br />clayey sand glacial till from the surface to the 20-foot <br />depth, with the top 1 foot being considerel the topsoil <br />layer. <br />Results of the percolation tests indicating these soil <br />absorptivities in minutes per inch (mpi) are as follows: <br />Surface <br />Soil At <br />lest M <br />Elevation <br />Test Depth <br />P-1 <br />102.4 <br />Sandy Clay <br />(CL) <br />P-2 <br />100.4 <br />Clayey Sand <br />(SC) <br />P-3 <br />101.4 <br />Sandy Clay <br />(CL) <br />P-4 <br />99.4 <br />Sandy Clay <br />(CL) <br />P-S <br />99.4 <br />Sandy Clay <br />(CL) <br />P-6 <br />97.7 <br />Sandy Clay <br />(CL) <br />Rate <br />m i <br />44 <br />240 <br />240 <br />4 <br />e�un. <br />ENGINEERING TESTING <br />