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MAY. 16.2006 2~51PM LEONARD RICE ENGRS N0.312 P.3i7 <br />Michelle L. Auatln and Darin Giron, P.E. pie 2 <br />' May 8, 2006 <br />The proposed replacement source is fully rronaumable weber loosed froth the City of <br />,,,,.' Anrade ("Arvada") and the St. Vraln Left Hand Water Conservancy t7isbict ("SVL.H"). If the mine <br />le dewetered and dry mined, water discharged from the pit during dewetering aperetlona that 1s In <br />excess of the legged Impacts of the dewatertng operation itself wilt be used as a roplacement <br />aouree in this plan. <br />The final rsclametion of the pit indudes baradilllnq or lining of all exposed gmundwa~rwtthln <br />the permk boundary. Th®applie:ant hoe bonded for lining and backfllling of the pk ae part of their <br />permit~ng process through the Division of Minerals and Geology. <br />Depletions <br />Ground water Is exposed at the site, The ground water exposed at this alto to eatimabed to be <br />2A acres with en annual deptedon of 70 acn-feet. All ground water at the site wan exposed eitisr <br />December 31,19Ct0. <br />The rorrailning uses at the nib are water lost in mined product, webr used for concrats <br />bathing and water used fordust suppression. The plan BpecMss thet44.2 acre•lbet O~ Water W111 be <br />removed in 1,500,000 tons of mined product, 2.0 acre-feet will be required for dust suppression and <br />1iS.S acre-feet will be requlrod for the produodon of 180,000 cubic yards of concrete. <br />If the pit is dewatered for dry mining, the plan astimatss that the panda wl II be dewaten3d at a <br />refs of 1,200 gpm for 8 hours a day, 385 days a year. The depletions resulting from dewsterlnp <br />pumping will be replaced under this plan. <br />The dspletons from evaporation, water removed In product, dust suppression end concrete <br />~~. batchlnq were lagged to the etr®am system using a abveranalysis and assuming a distance bo the <br />no flow boundary of 7.803 frost distance of the wen to the river of 2,640 feet, tranemleeivity of <br />150,000 gpd/R and specipc yletd of 0.2. <br />Replacements <br />The proposed source of replacement water for this pit is 127.25 sae feet of tUlly <br />consumable effluent leased froth Arvada for the period of June 2006 through Ocbbsr 2008 and <br />ApH12007 through October 2007 and 50.9 acre-feet of fully consumable water leased from 3VI.M <br />for the period of November 2006 through March 2007. The Arvada water wilt bs released tlrom <br />Metro wastewater Treatment plant and a flue percent transit Ions will bs accounted for to the <br />replacement. <br />If the alts Is dry mined, water discharged from the pit during dswetering operations that is <br />in axcesa of the lagged impacts of the dewatering operat~n Ibex will be used es a replacement <br />eoun~. Phor to claiming credit for the water discharged to the river as part of the dewabe~ng <br />process, the applicant must U~etell adequate measuring devices to allow proper adminlstretlon. <br />p. <br />The monthly depietlphs and roplacement requlremente ate found on the attaeched Tsbl® <br />Condltlons of Approval <br />As rraqulrod by Section 8 of Senate Bill 89-120, thle suba'fltute water supply plan has been <br />provided to an outside oonsuitant for review. I hereby approve the proposed sybstltube wethr <br />~`-' supply plan in accanianca with ~37'•fa0-137(11), C.R.S. subject b the following condiflone; <br />5ti~l 1D0/40D'd 1li~+l 01116999404+ eee~no»a a;rM ;o yip oio~0~d e0~91 90-eI~AVN <br />