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2. Tailings Acceptance from the Mill <br /> Wet tailings are produced in the flotation cells and are delivered to the 12000 gallon <br /> tailings tank in the underground mill. From this point, the tailings slurry will have <br /> approximately 30%solids which will be pumped to the new thickener located outside the <br /> filter building. This tank will dewater the slurry to approximately 40-50% solids. This <br /> slurry will be pumped to the 18000 gallon tailings tank in the filter building, which will <br /> then pump the slurry to the filter presses, located on the end floor of the filter building. <br /> These presses will dewater the slurry to the acceptable moisture content for compaction, <br /> which is expected to be in a range of 13%to 18%moisture, or 82-87% solids. <br /> It is expected that tailings production could be in a range of 2000-5000 tons per month. <br /> All tailings are very fine, since the material has been crushed and then ground in a ball <br /> mill underground. A representative size breakdown of the tails is shown in Appendix A, <br /> which is a sample of tails while the mill was under test operation in 2015 but is <br /> representative of the tailings to be produced over time. <br /> According to the DRMS Permit,the tailings produced from the mill must be classified as <br /> inert to be placed in the permanent embankments. Testing over years has shown that a <br /> certain small percentage of iron sulfide in the tailings is acceptable since it refuses to <br /> oxidize in any test. However,large percentages of iron sulfide or other metal sulfides will <br /> mean that the tailings may not be classified as inert, which will be difficult to deal with. <br /> Obviously, the mill has a major incentive to get as much metal sulfide out of the flotation <br /> cells as possible since this material is sold. Based on SPLP leach tests of tails in 2015,the <br /> tailings are classifies as inert. If there are significant deviations from these tailings, this <br /> must be evaluated through a new SPLP test. <br /> Rules: <br /> a- Tailings can only be accepted by the surface crew in charge of removing and <br /> placing the tails in the embankment when the tails are between 13.0% to 18.5% <br /> moisture and a pH between 7.5 and 10.5. These tests must be performed in the <br /> concrete floor of the filter bays, where the tails drop from the filter presses. They <br /> 2 <br />