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..~;. <br /> <br />Memo to Berhan Keffelew 2 July 29. 1994 <br />not necessarily be deleterious if the gravel 'is uniformly distributed <br />in the soil. The Division's inspections should focus on a determination <br />that a segregation of gravel into pockets that contain little or no fine <br />grained soil is not occurring within the soil liner fill. Published <br />research (Shakoor and Cook, 1990) indicates that the hydraulic <br />conductivity of a compacted, clayey soil was insensitive to the amount <br />of gravel present, as long as the gravel content did not exceed 50 <br />percent. The operator's test pad analyses using a sealed single ring <br />infiltrometer indicate that the gravelly Ironclad tails can be compacted <br />to a very low permeability. Low permeability is further assured by the <br />operator's commitment to utilize a material with minimum plasticity <br />index of 10 percent, and the permeability of the soil liner will be <br />measured (initially) by one permeability test for each 5,000 cubic yards <br />of fill that will be placed. <br />cc: Jim Pendleton <br />Jim Dillie <br />Carl Mount <br />Reference: <br />Shakoor, A. and B.D. Cook. 1990. The effect of atone content, size, and shape on the <br />engineering properties of a compacted silty clay. Bulletin of the Association of <br />Engineering Geologists. Vol. 27, No. 2: 245-253. <br />C:\WP51\CRESSON7 <br />