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Home My WebLink AboutDRC-2010-002463 - 0901a068801731c6•rA/Jj ^«i.^^2^-3oio-'^'oa'^a-5 Oenisan Mhws (USA) Corp. 105017th StfBOt, SuttB 9W DENISON^^^^ l« IfAP onm KI USA MINES \tf> r, '^'l/'S'Onof iJ?/ Tel:303628-7798 Fu:303 389>4129 (ienlsonfflinos.com March 12, 2010 VIA PDF AND FEDERAL EXPRESS Dane L. Finerfrock Co-Executive Secretary Utah Water Quality Board Utah Department of Environmental Quality 168 North 1950 West P.O.Box 144810 Salt Lake City, UT 84114-4810 Dear Mr. Finerfrock: Re: State of Utah Ground Water Discharge Permit No. UGW370004 (the "GWDP") for the White Mesa Uranium Mill - Notice Pursuant to Part LG.l(a) The White Mesa Mill (the "Mill") completed its 1^' quarter 2010 groundwater sampling under the GWDP on January 18, 19, and 20, and February 2, 3, 9, and 10, 2010. Not all results from these sampling dates have been received. Partial results were received in reports dated February 9, 10, and 26, 2010. In addition, field parameters were taken on January 13, 18, 19, and 20, and February 2, 3, 9, and 10, 2010. These are the first samples required to be taken under the January 20, 2010 revision ofthe GWDP. Under the January 20, 2010 revision ofthe GWDP, gj-ound water compliance limits ("GWCLs") have been determined on a well-by-well basis to reflect background groundwater quality, as defmed by the mean plus second standard deviation concentration, or the equivalent. Accordingly, the GWDP requires that constituent concentrations in each monitoring well shall not exceed the GWCLs set out in Table 2 ofthe GWDP.' ' It should be noted, however, that, because the GWCLs have been set at the mean plus second standard deviation, or the equivalent, un-impacted groundwater would normally be expected to exceed the GWCLs approximately 2.5% ofthe time. Therefore, exceedances are expected in approximately 2.5% ofall sample results, and do not necessarily represent impacts to groundwater from Mill operations. Pursuant to Part I.G.l.a) of the GWDP, please take notice that the concentrations of the following constituents in the following monitoring wells sampled on January 20, and February 2 and 10, 2010 exceeded their respective GWCLs in Table 2 ofthe Permit: Table 1 - GWCL Exceedances for the Quarter Monitoring Well MW-11 (Class II) MW-14 (Class III) MW-23 (Class III) MW-24 (Class III) MW-26 (Class III) MW-27 (Class III) MW-28 (Class III) MW-30 (Class II) Constituent ^ Tetrahydro friran Field pH Field pH Cadmium Field pH Nitrate + Nitrite Uranium Chloroform Chloride Nitrate + Nitrite Field pH Selenium GWCL (ua/l) 11.5 6.5-8.5 (pH S.U.) 6.5-8.5 pH S.U.) 2.5 6.5-8.5 (pH S.U.) 0.62 41.8 70 58.31 5.6 6.1-8.5 (pH S.U.) 34 Sample Result (Hfi/l) 12 6.32, 6.42, 6.44, 6.45 (pH S.U.) 6.31, 6.38 (pH S.U.) 2.63 6.4 (pH S.U.) 1.3 58.7 700 71 5.8 5.85, 5.83 (pH S.U.) 40.6 Because new GWCLs were set in the January 20, 2010 revision of the GWDP, all of the foregoing exceedances are new exceedances. DENISO MINES r/>ii Unless the compliance status for any constituents in any wells is determined otherwise by the Executive Secretary, the Mill will, pursuant to Part l.G.l.b)l) of the Permit, commence or continue, as the case may be, accelerated sampling of each of the foregoing constituents in its respective well on a monthly or quarterly basis, as applicable, as set forth below: Table 2 - Accelerated Monitoring Requirements as of March 12, 2010 Monitoring WeU MW-11 (Class II) MW-14 (Class III) MW-23 (Class III) MW-24 (Class III) MW-26 (Class III) MW-27 (Class III) Constituent Tetrahydro ftiran Field pH Field pH Cadmium Field pH Nitrate + Nitrite Uranium Chloroform Chloride Nitrate + Nitrite Normal Frequency of Sampling Quarterly Quarterly Semi- Annually Semi- Annually Semi- Annually Quarterly Quarterly Quarterly Quarterly Semi- Annually Accelerated Frequency of Sampling Monthly Monthly Quarterly Quarterly Quarterly Monthly Monthly Monthly Monthly Quarterly Commencement of Accelerated Monitoring July 2010 July 2010 Third Quarter 2010 Third Quarter 2010 Third Quarter 2010 July 2010 July 2010 July 2010 July 2010 Third Quarter 2010 DENISO MINES J>ii Monitoring Well MW-28 (Class III) MW-30 (Class II) Constituent Field pH Selenium Normal Frequency of Sampling Semi- Annually Quarterly Accelerated Frequency of Sampling Quarterly Monthly Commencement of Accelerated Monitoring Third Quarter 2010 July 2010 If you have any questions or require any ftirther infonnation, please contact the undersigned. Yours truly, Jo Ann S. Tischler Director, Compliance and Permitting cc: David C. Frydenlund Ron F. Hochstein Ryan Palmer Harold R. Roberts David E. Turk DENISO MINES J>U