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STATE OF COLORADO _ <br /> MINED LAND RECLAMATION DIVISION it <br /> Department of Natural Resources 1313 Sherman St.,Room 215Denver,CO 80203 <br /> 303 866-3567 <br /> FAX: 303 832.8106 <br /> Roy♦comer. <br /> Governor <br /> Fred R.Banta. <br /> December 28, 1989 Division D"ector <br /> Mr. Frank M. Graham, Jr. <br /> Western Mobile, Inc. <br /> P.O. Box 21588 <br /> Denver, Colorado 80221-2425 <br /> RE: Deepe Pit Hydrologic Impact Analysis Report and <br /> Irriqation Ditch Owner's Aareement <br /> MLRD File No. M-81-302 <br /> Dear Mr. Graham: <br /> I have reviewed the report entitled "Hydrologic Impact Analysis of Dewatering <br /> Flatiron Sand and Gravel Stage 4 and 6 at Deepe Pit", dated Auaust 1988 and <br /> prepared by Leonard Rice Consultina Water Engineers, Inc. After discussing <br /> the report with Senior Reclamation Specialist Steve Renner, we believe some <br /> additional information is necessary. <br /> Paae 1 of the Dewatering report, under "Existing Groundwater Conditions" , <br /> states: "The alluvium is moderatV y permeable with a hydraulic conductivity <br /> that ranges from 80 - 1200 apd/ft and averages 200 apd/ft2." Please have <br /> Leonard Rice submit to us the testing methods, test data, and calculations <br /> that were used to arrive at these values. <br /> Plate 2 of the Dewaterinq Report is titled "Impact of Pit Dewaterino - Stage 6 <br /> - Deepe Pit": however, under the "Explanation" legend, the projected water <br /> surface contours are labeled "Lines of equal increase in depth to water, due <br /> to dewatering of Stage 1 and 4. " It appears this should read "Stage 5. " <br /> Please have Leonard Rice address this discrepancy. <br /> The Water Level History Chart supplied for eight monitoring wells near Stages <br /> 4 and 6 appears to use several different datums as references for the water <br /> surface. First, what are the elevations that Monitor Wells A, B, C, and D are <br /> being referenced to? For example, Monitor Well "A" ' s readino on October 28, <br /> 1988 shows "-5.0" . What is the reference elevation that the water level is <br /> five feet lower than? Second, the North Test Hole #8 readings reference <br /> changes twice, first from Mean Sea Level to something that appears to read <br /> "Below 2" pipe", and then to "Below 4"". Please provide the elevation of <br /> the 2" datum and the 4" datum that you are referencing. Third, the readings <br /> in the wells labeled "Lake Hub" , "Farm House" , and "S Test Hole #11 " all <br /> changed references at the April , 1988 readina. For each of these three wells, <br /> what are the elevations that the water levels are being referenced to? <br /> I have also reviewed the February 4, 1985 "Agreement Regarding Sand and Gravel <br /> Mining and Augmentation Plan Pertaining Thereto." This agreement appears to <br /> i <br />