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-9- <br />• <br />Sieve Size % By Weight Passing <br />8-inch 87.1 <br />6-inch 68.7 <br />3-inch 55.1 <br />1.5-inch 43.1 <br />3/4-inch 33.1 <br />3/8-inch 24.9 <br />No. 4 16.3 <br />No. 8 10.2 <br />No. 16 6.6 <br />No. 30 4.8 <br />No. 50 3.7 <br />No. 100 3.0 <br />No. 200 2.3 <br />As indicated in the table above, the sample contains only 2.3 per- <br />cent passing the No. 200 sieve and about 10 percent passing the <br />No. 8 sieve. It is our opinion that compaction will further break <br />down the spoil and the actual permanent disposal areas will have <br />• more fine material than indicated by this gradation test. <br />Permeability <br />In a loose state, the spoils have very, very high permeability. <br />The material is an angular broken rock consisting of sandstone and <br />shales. After compaction, these materials will decrease in perme- <br />ability. The method of placement, as well as the type of compaction <br />may have signifcant influences on the permeability. For purposes of <br />evaluating the possibilities for saturation, we estimate the over- <br />all permeability of the fill to range between 100 and 1,000 feet <br />per year, with the 1,000 feet per year a more likely figure. Place- <br />ment of the fill in layers and the possibility of developing highly <br />compacted surfaces increases the risk of the horizontal permeability <br />• being greater than the vertical permeability. For the preliminary <br />