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''C VIL RES~URCES,LLC <br />ENGWEEft9 ~ PLANNERS <br />April 15, 2005 <br />Mr. Tom Schreiner ~ryti I E CuuJ~ <br />Division of Minerals and Geology c/ <br />1313 Sherman Street, Room 215 ~'`ii1°" "" ~ ° "'' ~ " ° '"nk',' <br />Denver, Ca 80203 <br />RE: Response to Second Adequacy Review Hydrology Comments (DMG Memo April 8, 2005); <br />Lupton Lakes Reclamation Permit Application - M-2004078/ <br />Dear Mr. Schreiner: <br />Thank you for discussing the comments and proposed responses via telephone in advance of our formal <br />submittal. We believe that the additional in-site that you provided during this conversation has helped us <br />draft more complete and direct responses to your comments as stated on the 2"' Hydrology Review <br />Memorandum to Erica Crosby and Carl Mountdated April 8, 2005 regarding the Lupton Lakes Reclamation <br />Permit Application No. M-2004-078. <br />Comment 1: The "Weft Location & Hydrologic Features Map" contains a variety of important ... <br />Response 1: The map has been increased in scale and subsequently printed. <br />Comment 2: The applicant clarified that water from pit de-wafering operations will be discharged at a <br />rate of 45 cfs.... <br />Response 2: The original and revised Mining Plan Maps showed this third point of discharge being <br />included, however, after further discussions with Erica Crosby indicating that proof of <br />existing easements would be required immediately, we have subsequently decided to <br />abandon the third point of discharge for this application. <br />We agree that stabilization to prevent erosion at the southernmost point of discharge from <br />the site is necessary. The operator wil! stabilize this area per Division review and <br />approval prior to discharging from the site at this point. <br />Comment 3: The revised "Mining Plan Map, 3 of 7"depicts 19 distinct units, each less than 25 acres in <br />size while the original... <br />Response 3: The groundwater mining impacts were modeled using six phases designated Mt through <br />M6. This is confusing and should have been labeled GW1 through GW6 to distinguish it <br />from the mining phases. Each groundwater (GW) phase approximately sixty acres in size <br />and was modeled with constant head nodes at the mine perimeter and allowed to reach <br />equilibrium. Setting the perimeter of each mining area to a constant head equal to the <br />bedrock elevation forces these cells to represent a "dry condition" and results in the <br />maximum extent of drawdown that could result from mining two phases (which is the <br />maximum mined dewatered area the permit would allow). The maximum extent of <br />drawdown from each phase was then superimposed upon the maximum extent of <br />drawdown from the other phases to form the overall maximum extent of drawdown for the <br />project. <br />Erica Crosby (DMG) and Danna Ortiz (Civil Resources, LLC) are working on or have <br />agreed to terms that specify that lining of the first two phases (50 acres max cumulative) <br />451 ^AK STREET, SUITE 2~9 1 P. O. BOX 66^ /FREDERICK, CO BO53~ • (3Q3) 833-1416 • (3031 833-Z85^ - FAx <br />