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Assumptions: <br /> - Bulkheads or constructed wetland remediation are <br /> technically feasible. <br /> - Project would be 70% effective for metal loading <br /> reduction. <br /> - Projects are feasible from an ownership and <br /> liability standpoint. <br /> - Flows were either the average of available flow data <br /> or constant if only one measurement was available. <br /> C. BMP Projects <br /> Methodology: <br /> - Tailings Ponds were sampled . <br /> - Mine dumps and related disturbances were sampled <br /> based on field paste pH . <br /> - Samples were analyzed for total metals. <br /> - Samples were analyzed for dissolved metals using <br /> TCLP-1312 exposure method . <br /> - Samples were analyzed for dissolved metals after a <br /> 1: 1 sample:water 30 minute bath. <br /> - A stormwater sample was taken at one of the sites <br /> for comparison to the prediction methods. <br /> - Annual precipitation data was collected from two - <br /> weather stations (Silverton and Red Mountain) . <br /> Annual precipitation amounts were assigned to each <br /> site based on elevation @ 1/4 intervals between the <br /> weather stations (all sites are at or between the <br /> elevations of the weather stations) . <br /> - Other factors were noted (i .e. if surface flows <br /> exist or if groundwater is thought or known to be <br /> present) but not included in the evaluation to- <br /> date. <br /> - Areas and volumes were roughly measured or <br /> estimated for initial evaluation. <br /> Assumptions: <br /> - TCLP-1312 exposure method is applicable in high <br /> water to solid ratio exposures ( i. e. groundwater or <br /> surface water flow exposures) . <br /> - A 1: 1 water-bath exposure method is applicable for <br /> most precipitation events. <br /> - A 98% cleanup efficiency can be achieved over time <br /> for tailings BMP Projects. <br /> - A 95% cleanup efficiency can be achieved over time <br /> for mine dump BMP Projects. <br /> - 100% of average precipitation is available for metal <br /> transport. <br /> - Projects are feasible from an ownership and <br /> liability standpoint . <br /> - 6 - <br />