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<br />The confined overburden aquifer will be replaced as a result of the Wining <br />operation by an unconfined aquifer [hat will b' more permeahle Thar. the <br />overburden aquifer. In addition, the potential recharge capacity will be <br />greater in the mine-plan area following reclamation. The increased recharge <br />capacity is not expected to ha•:e a significant impact on ground-water quantity <br />because only ~ percent of the Twent}•mile lark ground-water basin is recharged <br />from the affected area. The eater discharged into the ground-:,ater system <br />from the spoils acuifer will be higher in total dissolved solids and will be a <br />sulfate rather than the present bicarbonate t?•pe. T'nis aquifer discharges <br />ultimately in Po i•ish Creek. A state-of-the-art le:,chinh study conducted by <br />Dr. Herbert Gardner (llSD.4, 1979) concluded c},a' m ound-water quality will <br />return [o baseline conditions 7G years af[._•r reclamation i:: completed. <br />Similar information f:-om the nearby Edna r..ine indicates that baseline <br />conditions will be reached 7fJ0 years after mining in an adjacent basin. <br />Because of this variable time period, OSM and the State requested that En^_rgy <br />Fuels model solute transport to determine t•ne decrease in wale: quality caused <br />by dissolved solids (primarily sulfate salts). The model shcwed that t'nere <br />would 6e very little impart to ground-water quulit;; in the Twen*_vmile Par',: <br />ground-water basin, and that these impacts would lessen with time. In <br />addition, chemical analyses of the over~nurder. and leaching tests performed on <br />the spoil indicate :here are no toxic materials in the cverburden. <br />Energy Fuels plans to open two bor. cuts at one ~~ear intervals. :~n[er .`rom the <br />overburden acuifer •will be pumped from these box cuss at a maximu;~ rate of <br />28,000 gallons per day during the second year of mining. DewaterYng should be <br />reduced to Near zero in the fifth year of a,inir~. The d:awdow•n associated <br />with this pumr,ing w;,s projected and is not er.pec[ed to be measurable more than <br />5,000 eet a.:av from ti,e host cu[. ldacer pur.ped from the pits will be placed <br />in settlin; ponds ~o remove any sediment. i'•ecnnse dewaterin~ is temporar-;, no <br />adverse impacts to ground-water quantity should occur. <br />/n~rv h., Energy Fuels has installed 47 ground-water monitoring wells to detect chanf;es <br />in ground-crater levels and quality at the site and in the affected area. OS"1 <br />~•~" °~r-~ j has determined that ti,e company has enough wells to monitor any potcn::al <br />effects of the proposed operation on the T::e~nivmilc Park ground-water 'uasin. <br />OSF1s analysis of the around-'-ater data submitted by Energy Fuels -indicates <br />that there will be short-term effects to the ground-water system that include <br />increased postminine recharge rate, leachinc cf so'_uble ions in baci;filled <br />areas, partial dewy:ering of the overburden aquifer, and temporar draw•down of <br />water levels in adjacent areas. The concentrations of dissolved solids will <br />be increased for a period o`. at leas: '4 years. This is not anticipated to be <br />a significant increase because of the dilution that will occur within [he <br />Twentvmile Part ground-:rater be,sin. Thc• compnn,' n~~ins enough senior water <br />rights in the general area to replace any water rights that r..ight he injured <br />in Che process of ,r.ining and i,a~:e ,ommitter: to this *•_placemr•n[ in the mina <br />plan. 6a s•_d on US'Is an~ly sts, [here will be nn -,ipnif lean[ short- or <br />long-term environmei;tal impacts to [he ground-w,,,er system from the proposed <br />mining operation. <br />- 10 - <br />