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Top 33 386,741 Top 32 79,429 <br />173 Aditsi 434,547 Tap 158 88,602 <br /> Estimated oast to rem,ediate in 51000's <br /> Phase 1 Phase 2 Option 1 <br />Top 33 S 12,105 S 20,550 Tap 32 S 8,175 <br />Top 77 $ 20,550 S 31,830 Top 127 S 21,960 <br />Load Removed in paands/year <br />Phase 1 Phase 2 Option 1 <br />Tap 33 128,041 194,275 Top 32 50,494 <br />Top 77 138,834 208,945 Top 127 54,618 <br />Cost pound/year <br />Phase 1 Phase 2 Option 1 <br />Top 33 S 94.54 S 105.78 Top 32 S 161.90 <br />77 Adits 5148.Oi 5152.34 Top 127 S 402.10 <br />*Total oast divided by load removed. <br />Clearly there are diminishing returns in treating both edits and mine waste. The <br />top 33 edits account for 89`/0 of the load and under phase 1, it would cost $12.5 illion to <br />treat them. To treat the additiona111% of the load would add $8.5 million. The contrast <br />is more stark under mine waste_ The top 32 sites account for 90'/0 of the load and would <br />cost just over $8 million to treat. Treating the additional 10% would add almost $14 <br />million. <br />The phase 2 edit scenario includes removal of large quantities of Fe and Al from <br />the Paradise portal. In fact, 8I% of the difference in load removed between phase 1 and <br />phase 2 for edits can be attributed to phase 2 remediation of the Paradise alone. Under <br />phase 1, no reductions in metals from the Paradise are amacipated because a more <br />thorough investigation of the site will be the first step_ With the exception of this one <br />site, there is little difference in reductions of metals between phase 1 and phase 2. <br />Moreover phase 2 would only be implemented if phase 1 did not result in projected <br />reductions_ Therefore, without the Paradise and its associated phase 2 remediation costs <br />of $1 million, the difference in costs between phase 1 and 2 can bethought of as a range <br />of costs associated with a total loading reduction for edits of approximately 170,000 to <br />180,()00 pounds per year_ <br />Remediating the Paradise portal and another site, the Eerrocrete mine, is <br />problematic_ They are both shallow workings in the Mineral Creek drainage and lie near <br />the base of valleys. The mines are thought to have intersected the relatively shallow <br />groundwater that wells up at valley bottoms creating the area's infamous iron seeps and <br />bogs. Metal loading may well be the result of natural geological processes that is carried <br />into the mine through groundwater infiltration While treating naturally occurring source <br />loads (coming from edits) may be beneficial, discharges with high iron and aluminum <br />concentrations are expensive to treat because of high production of sludge which needs <br />disposal plus frequent system maintenance_ These edits are also collapsed, indicating that <br />they were constructed in highly fiactured rock making it unlikely that bulkhead seals <br />Revised 7/15101 from 133 edits <br />22 <br />