2011-10-25_REVISION - M1977300 - Laserfiche WebLink

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IRIS MITIGATION AND DESIGN, INC. Environmental Consulting IRIS MITIGATION AND DESIGN, INC. 3450 W. 32 Avenue, 2 Floor Denver, Colorado 80211 Phone: 720 - 272 -1985 bleisure@irismitigation.com which will allow the Cotter Corporation (N.S.L.) (Cotter) to develop and implement a long -term, sustainable reclamation plan for the site. The long -term sustainable reclamation plan will include returning Ralston Creek flows and completion of all required Preble's Meadow Jumping Mouse (Zapus hudsonius preblei) (Preble's) mitigation. Since the characterization and reclamation activities cannot be completed until the alluvial fill is substantially dewatered, many of the details of Phase 3 have not yet been determined The first and second phases of the Project involve design and construction of proposed cutoff walls and bypass systems, whereby Preble's habitat impact can be readily identified and quantified. Characterization and reclamation activities can be accomplished far more efficiently if the hydrologic connection between Ralston Creek and the alluvial fill can be controlled to allow excavation activities to occur in relatively dry conditions rather than having to continually, actively manage groundwater in areas that may potentially be contaminated. Phase 3 involves in -depth site material testing and characterization before the long term site reclamation plan can be finalized and executed. The site material testing and characterization process may take up to 2 years to complete at which time Preble's habitat impact will be identified and quantified. A final site restoration plan, including completion of all outstanding mitigation from previous and current phases, will also be finalized and executed. The actual site clean -up and restoration could take between 5 to 10 years depending on the extent of remediation needed. You will be consulted through the U.S. Army Corps of Engineers (USACE) permitting process on all three phases of the Project. We will work together on the Phase 3 final restoration plan to include all remaining Preble's habitat mitigation obligations and to improve Preble's habitat both along the Ralston Creek corridor and throughout the adjacent upland areas (up to 400 feet cross - gradient from the edge of Ralston Creek). The overall goal of the project is to clean up the site and to restore it to natural conditions with a restored riparian corridor and adjacent upland habitat for wildlife including Preble's habitat. The restored riparian corridor will create a corridor for Preble's use of the site for feeding, nesting, and hibernating as well as a travel corridor for the Preble's up and downstream. The short term low to medium quality Preble's habitat impact during the phased cleanup of the site will be far outweighed by the long term restored Preble's habitat once the site cleanup is complete. Schwartzwalder Mine Phase 1 Page 2 October 2011 Response to USFWS Comments