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For the column deposition tests, samples of the total <br />tailings product were slurried into five-inch diameter columns. <br />The tailings were deposited in three lifts. Two columns were <br />used; one column with bottom drainage and one without. At the <br />conclusion of the settlement studies the columns were charged <br />with deionized water and values of permeabilities were <br />calculated for the column having bottom drainage. <br />Test results indicate a range of densities, depending <br />on whether bottom drainage was allowed during deposition and <br />subsequent settlement. The settled dry density values ranged <br />from 75 pcf with no bottom drainage to 85 pcf' with bottom <br />drainage. The permeabilities ranged from 2.5 x ll0-s cm/sec to <br />5.0 x 10-6 cm/sec. <br />The tailings box tests involved the deposition of the <br />tailings in a similar manner to that which would occur on the <br />impoundment beach. The tests were performed by placing a number <br />• of thin lifts of tailings. Observation was made during the test <br />of the physical movement of the material. Measurement of the <br />resulting beach angle, material segregation, and density of <br />the deposited slurry with time were then made. <br />The tailings were observed to beach at an average slope <br />across the box of 2.9 percent with a range fram 0.3 to 5.5 <br />percent. In-place dry densities following initial sedimentation <br />of the tailings solids were measured at between 69.4 pcf to <br />75.6 pcf. Material segregation tests indicated .a decrease in <br />grain size from the discharge point with the sand fraction <br />remaining adjacent to the discharge point. <br />In addition, the tailings box was sealed to allow control <br />of the air flow over the tailings. The air was cycled at a <br />controlled rate through the box and then through a trap filled <br />with a sodium hydroxide solution. The sodium trap was designed <br />to capture the free cyanide in the air and allow measurement <br />of the amount of volatilization of cyanide which could be <br />D-28, <br />