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-33- <br />quality in the deep subsurface disposal site. Two separate testing <br />procedures were conducted in order to determine the water content of <br />the leached rock below which rapid gravity drainage would not take <br />place. <br />The first method is the centrifuge moisture equivalent (ASTM <br />D -425). This test subjects a saturated sample of the material to a <br />force equal to one thousand times gravity for a period of one hour. <br />The centrifuge moisture equivalent (CME) is the moisture content <br />expressed as a percent of dry weight at the completion of the test. <br />The centrifuge moisture equivalent for this type of material is equal <br />to the moisture content at which rapid gravity drainage ceases. <br />The second test procedure was developed in our office to model <br />the conditions in the waste rock storage pile and the disposal area. <br />_ri :ially, a relative density test (ASTM D -2049) and a gradation <br />analysis were conducted on the run-of -mine ore. Relative density is <br />defined as the state of compactness of the soil with respect to its <br />loosest and most compact state. The relative density of a soil in <br />place is expressed as a percentage of the difference between the <br />- )osest and most compact conditions. This information is important <br />:c tne permeability of a granular material such as the low - grade <br />..._= ore :s dependent on the density. <br />Next, the low -grade ore was subjected to acid leaching, washing, <br />neutralization and a two -day drainage period to simulate the vat leach <br />process. At the completion of the two -day drain period prescribed by <br />the mining process, a moisture content sample of the leached rock was <br />placed in four 15 -indh high columns. The material in two of the <br />