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CIVIL RES~URCES,LLC <br />ENpINEERS ~ PLANNERS <br />Mamh 22, 2005 <br />Colorado Departrnent of Transportation <br />Mr. Joe Intennill <br />43379 Highway 51 <br />Ault, CO 80610 <br />RE: SW TKO Joint Venture, LLC, Division of Minerals and Geology Application M•2004.079 <br />Lupton Lakes Resource; CDOT Objection Letter <br />Dear Mr. Intermill: <br />The Division of Minerals and Geology (Division) forwarded us your concems about the proposed gravel <br />mining operation/water storage reservoirs in a letter dated March 17, 2005. Following is our response to <br />your concems. <br />The westem reclaimed shoreline in proximity to US Highway 85 is over one-half mile in length. CDOT is <br />concerned of wind and water erosion along the westem shoreline of the reclaimed prt. Please address the <br />effects of wind and water erosion around the reclaimed pond on all pond slopes. The applicant will need to <br />provide detailed designs of erosion control features such as rock armoring or other suitahle measures. <br />The proposed maximum water surface elevation for Pond 2 (closest to Highway 85} is 4,93 .5 ft-MSL. The <br />ground surface along the westem margin of Pond 2, parallel to Highway 85, ranges in elevations from 4,940 <br />ft-MSL to 4,944 ft-MSL. This provides freeboard ranging from 2.5 feet to 6.5 feet at the maximt:m water <br />surface level. <br />The embankment wilt be zoned with an inner core of low-permeability clay material (Zone 1) and a twelve- <br />foot wide (measured horizontally) zone of erosion protection (Zone 2). The Zane 2 material has been <br />approved for jurisdictional dams by the State Engineers Office (Dunes and South Platte Reservoirs) as a <br />recognized erosion control measure. The Lupton Lakes project has been reviewed by the SEO and has <br />been classified as anon-jurisdictional slope liner (Letter from Jack G. Byers, Deputy State Engineer, dated <br />February 14, 2005). Regardless, the project will include the Zone 2 clayey gravel soil meeting the following <br />criteria: <br />Sieve Size Percent Passing <br />7" 100 <br />1-1/2" 80-100 <br />No.4 35-55 <br />No. 200 17 - 30 <br />°No less than 80% passing the 1 Y:"sieve. <br />°Unified Soils Classification: GC, GC-SC <br />Zone 2shall be swell-graded mixture of 12" of sand, gravel, and cobbles left behind from mining operations <br />and 6" of weathered claystone bedrock. Where the gravel and cobble layer is less than 12", additional pit <br />run will be added. <br />451 ^AK STREET, SUITE 209 ~ P.O. BOX 6H^ ~ FREDERICK, CO BOS3O ~ (303I 833-1 47 6 ~ (3031 833-2850 - Fnx <br />