2011-10-25_REVISION - M1977300 - Laserfiche WebLink

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z October 25, 2011 Mr. Peter Plage U.S. Fish and Wildlife Service Colorado Field Office - Ecological Services 134 Union Boulevard - Suite 670 Lakewood, CO 80228 Dear Peter, IRIS MITIGATION AND DESIGN, INC. Environmental Consulting z IRIS MITIGATION AND DESIGN, INC. 3450 W. 32nd Avenue, 2nd Floor Denver, Colorado 80211 Phone: 720 - 272 -1985 bleisure@irismitigation.com We have reviewed your comments to the Biological Assessment for the Schwartzwalder Mine proposed Phase 1 work and have prepared the following responses to your comments: Comment 1: We should have a more directed explanation that the larger project may last 5 to 10 years, but it should provide a substantial increase in Preble's habitat quality /connectivity over the long term. That's what I need to be comfortable with this first consultation. Given that as context, impacts to Preble's in this first phase will not be offset by the conservation measures (mitigation and restoration) provided. I would imagine this is both due to the ongoing disruption of the project (i.e. restoration must wait) and that excellent opportunities for the Preble's exist in Phase 3. That combined with the DRMS bond should justify phasing it. Response 1: A phased approach is necessary for this Project because additional site characterization work is needed to delineate areas of contamination and to formulate long -term reclamation plans for the site: • Phase 1: Upstream Cutoff Wall and Low Flow (8 cubic feet per second [cfs]) Bypass Pipeline • Phase 2: Temporary Diversion Pipeline (100 cfs) and Downstream Cutoff Wall • Phase 3: Characterization and Long -term Reclamation - The third phase of the Project will include characterization of the extent and magnitude of contamination on the site Schwartzwalder Mine Phase 1 Page 1 October 2011 Response to USFWS Comments