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~ STATE DF COLORADO <br />MINED LAND RECLAMATION DIVISION <br />De rtmem of Natural Resources I ~pF'cp~r <br />1Denver CG 80203 Room 215 111 `II'll'IIIIII'll ~~ % "[.~ ~'$ <br />303 866-3567 {11 ~~~~ <br />e <br />Fax. 303 6328106 <br />Roy Romer. <br />Go~errxr <br />Fred R. Bane. <br />DATE: May 9, 1990 D~nsan Drtrlor <br />T0: Mike Boyd /~%¢, <br />FROM: Tom Schreiner ~ {~O' <br />RE: Hydrologic Review - Adequacy Comments, Virginia Acres Pit, <br />File No. M-90-021 <br />I have reviewed the United Companies of Mesa County application fora mining <br />and reclamation permit and offer the following comments: <br />1. The Division recommends that a berm be constructed along the south and <br />east portions of the permit boundary adequate to withstand the flow of a <br />1C~0-year flood. The berm should include a minimum freeboard of 1.0 foot <br />above the water surface elevation for the 100-year flood. The berm <br />should also be capable of resisting erosion from frequent storm events. <br />Several options for design of a stable 100-year berm are available: <br />natural earth berm, soil cement, riprap, or riprap with vegetation. <br />Please indicate which design will be used and submit appropriate berm <br />size and supporting calculations. The berm design should include the <br />water surface elevation of the 100-year flood. <br />2. The side slopes of the proposed 8-acre pond should be sloped at a minimum <br />of 3:1 horizontal to vertical fora distance of 5 feet above to 10 feet <br />below the expected water line. The Division recommends a minimum slope <br />of 5:1 at select areas for creation of riparian habitat and/or areas <br />proposed for swimoning. <br />3. Please commit to compliance with the State Engineers Office requirements <br />for evaporative loss from the proposed 8-acre pond. (You may be required <br />to obtain a well permit or a substitute water supply plan due to <br />provisions of Senate Bill 181). <br />4. Please indicate the source and volume of water neeoed during production <br />an~i for fugitive dust control. Are additional water rights necessary? <br />If so, please verify that they will be available at the start of the <br />mining operation. <br />