2013-02-20_REPORT - M1977300 - Laserfiche WebLink

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tT IRIS MITIGATION AND DESIGN, INC. Environmental Consulting IRIS MITIGATION AND DESIGN, INC. 2022 Arapahoe Street Golden, Colorado 80401 Phone: 720- 272 -1985 bleisure@irismitigation.com ACC utilized much smaller stockpile areas in the upland habitat areas on either side of the creek than what was originally permitted (see Figures 7 and 9). 2011 Phase 1 Permitted Area Impact / 2012 Phase 1 Actual Area Impact Comparison The 2011 permitted area impact for Phase 1, as described in the BA and 404 Section permit request, is detailed on Table 1. The 2012 actual area impact following construction activities is detailed on Table 2. In comparing these two tables, the originally permitted 1.8 acres of impact to both upland and riparian habitat was reduced approximately 50 percent to 0.94 acre of actual area impact during construction activities. Of the 0.94 acre of actual area impact, 0.04 acre of permanent impact occurred to upland habitat as originally permitted (see Table 2). Of the 1.3 acres of temporary upland impact originally permitted, only 0.59 acre of temporary upland habitat was actually impacted (decreased impact of greater than 50 percent). Actual permanent impact to riparian area habitat was similar to what was permitted in 2011 at 0.09 acre. However, the temporary actual riparian impact was reduced from 0.36 acre to 0.22 acre (see Table 2). This reduction in actual area impact has created the need to recalculate the actual Phase 1 required mitigation to be completed at the end of Phase 1 and at the end of the larger valley clean -up (Phase 3). Revised Phase 1 Mitigation Plan Based on 2012 Phase 1 Actual Area Impact The 2012 revised Phase 1 required mitigation is shown on Table 2 and includes a total of 1.48 acres of mitigation for 0.94 acre of actual area impact. This mitigation will include area Schwartzwalder Mine Actual Area Impact Page 4 January 2013