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6 <br />DEERE & AULT CONSULTANTS, INC <br />DEREK FOSTER, P.E. <br />600 S. AIRPORT ROAD, BLDG A, STE 205 <br />LONGMONT, CO 80503 <br />RE: SLURRY WALL LINER APPROVAL - PROVISIONAL <br />STAGECOACH PIT, DRMS W1983 -067 (WDID 0203015) <br />S26135- T1S -R67W, WATER DIVISION 1, WATER DISTRICT 2 <br />Dear Derek: <br />The purpose of this letter is to provisionally approve the lining of the Stagecoach Pit. This liner is <br />located in the S'YZSWSW of Section 26 and the E'/SWNW and the NWNW of Section 35, all in <br />Township 1 South, Range 67 West of the 6 P.M. and is a part of the Stagecoach Pit (DRMS M -1983- <br />067). There is active mining occurring within the liner boundary with future mining to occur in the <br />southern portion of the liner boundary. The slurry wall liner leak test commenced March 26, 2012 and <br />concluded on July 2, 2012. A site inspection was performed by our office on March 28, 2012 to <br />review site conditions and the leak test plan. <br />Your report dated July 27, 2012 provides the liner summary and leak test result. The test data <br />provided indicates that the liner meets the design standard referenced in the August 1999 State <br />Engineer Guidelines for Lining Criteria for Gravel Pits (1999 SEO Guidelines) Meeting the design <br />standard requires that during reservoir operations all water inflows and outflows for the liner perimeter <br />enclosed area be accounted for on a monthly basis. <br />This liner approval is applicable only during mining operations at the site and does not classify the <br />structure as a reservoir capable of water storage. However, for the remainder of mining operations, <br />water within the liner boundary is now classified as trapped native ground water. The trapped native <br />ground water may be removed from within the lined area and returned to the stream system through <br />surface flow or ground water recharge without the need for replacement so long as the operator does <br />not put the water to beneficial use. All native trapped ground water remaining that is put to beneficial <br />use (except for the water removed in product) must be replaced by the operator. All inflow of water <br />into the liner boundary from any source, including precipitation and ground water inflows shall be <br />removed by the pit operator so as not to cause out -of- priority storage. In order for the liner to be <br />approved for water storage the operator must perform a final leak test once mining is complete <br />and the site is at final grade. The final leak test will be allowed to have a modified duration of <br />30 -days as long as the liner continues to satisfactorily operate during mining operations. <br />Please contact me at the number below if you have any questions. <br />Sincerely, Or <br />Alfleffalibo <br />Jona "an M. e z, P.E. <br />Water Resource Engineer <br />ec. William Schneider, District 2 Water Commissioner ( William .Schneider{a'2state_co.us) <br />WDID File (0203015) <br />DEPARTMENT OF NATURAL RESOURCES <br />DIVISION OF WATER RESOURCES <br />August 7, 2012 <br />Water Division 1 • Greeley <br />810 9"^ Street, Suite 200 • Greeley, CO 80631 • Phone: 970- 352 -8712 • Fax: 970- 392 -1816 <br />www.water.state.co.us <br />John W H ckenlooper <br />Governor <br />Mtke Ktn <br />Exee tive D <br />v Director <br />Dick Wolfe, 1'.E. <br />Dsrectorr5tale Engineer <br />David 1.. Nettles, P.E. <br />Division Engineer <br />