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4. Work Plan <br /> Remedial Goals and Objectives <br /> Cleanup of historic tailings, removal from contact with flowing water, severing existing <br /> direct connections to the river in order to reduce the impacts to the Animas River from dissolved <br /> metals. <br /> Site Loading Estimate <br /> For all of the remediation projects, and based on limited information, the site loading <br /> estimate for each project site was based on the following methodology <br /> Adits- <br /> Using available data, zinc loading was calculated based on the average <br /> flow and average zinc values. <br /> Mine Waste Dumps and Tailings Piles- <br /> Site composite soil samples were tested using a water bath extraction. <br /> This test consists of exposing a 1:1 ratio by weight of material to <br /> deionized water. The mixture is briefly mixed then allowed to set for 30 <br /> minutes. The sample was then filtered ( 0.45 micron) and analyzed for <br /> metals. Annualized loading was calculated using rainfall data <br /> (proportionally adjusted for site elevation between the Silverton and Red <br /> Mountain weather stations), exposed area of waste dump or tailings site <br /> and loading based on 1:1 water bath test results. For comparison to adit <br /> flow loadings projects, the annualized loading was converted to an average <br /> daily loading. <br /> Based on these assumptions and procedures, Sunnyside estimates that the average daily <br /> loading for this site may be as much as 43.0 pounds of dissolved zinc per day. Sunnyside is <br /> under no obligation to defend these estimates and they should only be used as an estimate. <br /> Sunnyside does not represent that its mitigation project at this site will remove any specific <br /> percentage of metals loading from this site: the loading estimate contained herein does not form <br /> the basis of an enforceable permit obligation. <br /> Description of Project <br /> Sunnyside will provide sediment catchments below the tailings to minimize sediment <br /> transport to the river during excavation. The tailings would be removed from contact with <br /> 46094_2,9//2,V6 B-7 <br /> "1� <br />