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<br />STATE OF COLORADO <br />MINED LAND RECLAMATION DIVISION of ~o~ <br />~ <br />Department of Natural Resources <br />R <br />215 <br />1313 Sh <br />St ~``~c~ <br />=~"'~~ <br />~! F <br />\1$ <br />erman <br />., <br />oom <br />Denver <br />C080203 ri <br />~ ~d/ ~ <br />, ~ ~ <br />303 8663567 ~ 1896 ~ <br />FA x: 303 832-8106 <br /> Ray Romer. <br /> Governor <br /> Fretl R Banta, <br /> Division Director <br />DATE: July 25, 1990 <br />T0: Gregg R. Squire <br />FROM: John T. Doerfer <br />RE: Hydrologic Adequacy Review, Howe Pit Amendment, <br />Mobile Premix Concrete, Inc., File No. M-78-052 <br />I have reviewed the hydrologic aspects of the above-referenced amendment <br />application. The proposal is to add about 150 acres to the existing 240 acre <br />sand and gravel pit adjacent to the South Platte River near 112th Avenue and <br />Brighton Road in Adams County. My comments following review are provided <br />below. <br />Exhibit D - Mining Plan <br />The mining plan describes the initial construction of <br />along the east side of the Stage 1 mining area and an <br />liner from Stage 1 to the shop area in Stage 0. The <br />upon reclamation occurs in this area. Will the liner <br />around the shoreline perimeter of the peninsula or by <br />the neck of the peninsula? <br />liner to occur <br />extension of the <br />peninsula to be left <br />be constructed <br />trenching across <br />Pumping of the pit is proposed. The construction of the liner will <br />mitigate long-term effects due to drawdown of groundwater levels as <br />stated in the application, however, there exists a potential for <br />immediate short-term effects from pumping prior to liner construction. <br />Please provide information which demonstrates there will be no adverse <br />effects from dewatering on the following: <br />The Fulton ditch; <br />The cottonwoods near the river; and, <br />The lake on the Hazeltine property. <br />The discussion under the primary reclamation plan states: "Generally <br />speaking, the embankments will be anchored into the shale floor with a <br />keyway." Under what conditions would a key not be necessary? It appears <br />the construction method which includes the keying of the liner into <br />bedrock will be necessary to insure a continuous impermeable barrier. <br />