Loading...
HomeMy WebLinkAboutDRC-2018-000483 - 0901a068807a218aJanuary 10, 2018 VIA PDF AND OVERNIGHT DELIVERY Scott Anderson, Director of Waste Management and Radiation Control State of Utah Department of Environmental Quality 195 North 1950 West P.O. Box 144880 Salt Lake City, UT 84114-4880 Energy Fuels Resources (USA) Inc. 225 Union Blvd. Suite 600 Lakewood, CO, US, 80228 303 974 2140 www.energvfuels.com Div of Waste Management and Radiation Control JAN 1 2 2018 DRC-ZOiS'OOO^&S Re: State of Utah Stipulation and Consent Order (“SCO”) Docket Number UGW-20-01 White Mesa Uranium Mill - Energy Fuels Resources (USA) Inc. (“EFRI”) Plan and Time Schedule, Revision 1, Pursuant to Part H.H.2 of the Groundwater Corrective Action Plan (“GCAP”) included as Attachment 1 to the SCO Dear Mr. Anderson: Part II.H.l) of the GCAP states that “At any time EFR[I] submits a quarterly report that demonstrates an exceedance (second quarter of chloroform exceedance), EFR[I] will provide a written exceedance notice to the Director (“Exceedance Notice”) for all wells that have demonstrated such an exceedance.” EFRI provided notice to the Director that the concentrations of chloroform in TW4-26 exceeded the respective GCAL of 70 ug/L for two or more consecutive quarters by letter dated November 27, 2017. Part II.H.2) of the GCAP requires that “Within 60 days after the time of submittal of a quarterly report that demonstrates an exceedance as defined in Part II.G, EFR[I] will provide a plan and schedule for remedial actions to address and resolve the excursion, for Director approval.” This is the revised plan and schedule in response to the Division of Waste Management and Radiation Control (“DWMRC”) comments as required under Part II.H.2) of the GCAP for TW4-26 for the third quarter of 2017. If you should have any questions regarding this submittal please contact me at (303) 389-4134. Yours truly, f ENERGY FUELS RESOURCES (USA) INC. Kathy Weinel Quality Assurance Manager cc:David Frydenlund, Mark Chalmers. David Turk. Logan Shumway, Scott Bakken, Paul Goranson WHITE MESA MILL State of Utah Stipulation and Consent Order Docket No. UGW-20-01 Plan and Time Schedule Under Part II.H.2 For Exceedances in TW4-26 in the Third Quarter of 2017 Energy Fuels Resources (USA) Inc. 225 Union Boulevard, Suite 600 Lakewood, CO 80228 January 10, 2018 1. INTRODUCTION Energy Fuels Resources (USA) Inc. (“EFRI”) operates the White Mesa Uranium Mill (the “Mill”), located near Blanding Utah. EFRI performed third quarter 2017 chloroform monitoring during the period from July 1, to September 30, 2017 under the September 14, 2015 Groundwater Corrective Action Plan (“GCAP”), included as Attachment 1 to the executed Stipulation and Consent Order (“SCO”). Part II.H.l) of the GCAP states that “At any time EFR[I] submits a quarterly report that demonstrates an exceedance (second quarter of chloroform exceedance), EFR[I] will provide a written exceedance notice to the Director (“Exceedance Notice”) for all wells that have demonstrated such an exceedance.” EFRI provided notice to the Director that the concentrations of chloroform in TW4-26 exceeded the respective GCAL of 70 ug/L for two or more consecutive quarters by letter dated November 27, 2017. Part II.H.2) of the GCAP requires that “Within 60 days after the time of submittal of a quarterly report that demonstrates an exceedance as defined in Part II.G, EFR[I] will provide a plan and schedule for remedial actions to address and resolve the excursion, for Director approval.” This is the plan and schedule required under Part II.H.2) of the GCAP for TW4-26 for the third quarter of 2017. 2. WELLS SUBJECT TO THIS PLAN The following well is covered by this Plan: Table 1 Chloroform Results in TW4-26 Constituent Monitoring Event GCAL (ug/L) Results (ug/L) Chloroform Q2 2017 Q3 2017 70.0 244 419 3. BACKGROUND The chloroform plume is currently entirely within the Mill property boundary and is bounded on all sides by wells having chloroform concentrations that are either non-detect or less than 70 pg/L (Figure 1). The plume is bounded to the north by TW4-25; to the west and southwest by MW-31, MW-32, TW4-23, and TW4-24; to the east by TW4-3, TW4-5, TW4-13, TW4-14, TW4-18, TW4-27, TW4-30, TW4-36 and TW4-38; to the south by TW4-34; and to the southeast by TW4-35. Chloroform pumping as of the third quarter of 2017 (4.8 gpm) exceeds calculated ‘background’ flow through the plume (3.4 gpm) and is therefore considered adequate. In addition, because of continued reductions in saturated thicknesses and hydraulic gradients 1 resulting from reduced wildlife pond recharge, ‘background’ flow through the plume is expected to continue to diminish, thereby reducing the pumping needed to control the plume. Because of the increase in chloroform at TW4-26 from approximately 46 in the first quarter of 2017 to 419 pg/L in the third quarter of 2017, TW4-26 no longer bounds the chloroform plume to the south-southwest. MW-17 bounds the plume to the far southwest (cross-gradient), and MW-22 bounds the plume far to the south (cross- to downgradient). At TW4-26, decreasing water level trends (since about the fourth quarter of 2013), and increasing concentration trends are also consistent with reduced wildlife pond seepage, in particular, reduced seepage from the southern wildlife pond. As the groundwater mound associated with the southern pond decays, groundwater flow directions in the southern extremity of the plume are likely to become more southerly, and plume migration is likely to turn more to the south. An increasingly southerly direction of plume migration is consistent with increasing concentrations at TW4-26. 4. PLAN AND TIME SCHEDULE This is a plan and schedule for actions to address and resolve the excursion noted in Table 1 above as required by the GCAP. Part II.H.2).i) of the GCAP states that the plan and schedule may include, but is not limited to the installation of one or more pumping wells in the vicinity of the well found in exceedance and installation of one or more replacement wells for the compliance well in exceedance. EFRI plans to address the exceedance through the installation of two wells (TW4-40 and TW4-41). Figure 2 shows 1) the proposed location of new compliance monitoring well TW4-40; and 2) the locations of proposed test borings (one of which will be completed as new chloroform pumping well TW4-41). As shown in Figure 2, the proposed location of new compliance monitoring well TW4-40 is approximately 200 feet south of TW4- 26, and the proposed test borings are located within the vicinity of existing pumping well TW4- 4. TW4-40 will be positioned cross-to downgradient of TW4-26. Because of groundwater flow directions that are increasingly southerly in this area, new well TW4-40 is expected to become increasingly downgradient rather than cross-gradient with respect to TW4-26. Pumping well TW4-41 is proposed to augment pumping well TW4-4 by increasing chloroform mass removal rates in this area. TW4-41 is proposed to be installed near TW4-4 rather than farther to the south in the toe of the plume because perched zone hydraulic conductivities south of TW4-4 are too low to allow a pumping rate large enough to result in significant chloroform mass removal. TW4-4 is located within a generally north-south oriented relatively high conductivity zone that is interpreted to ‘pinch out’ between TW4-4 and TW4-6. Because the precise southern extent of the higher conductivity zone is unknown, the test borings shown in Figure 2 are proposed to be installed in the vicinity of TW4-4 to attempt to intercept this zone. One of these test borings will be overdrilled and completed as new pumping well TW4-41. The test boring installation order is indicated by the labels 1 through 5. 2 The rationale for the test boring installation order is to gather the information needed to complete the new pumping well as far as possible to the south while remaining within the higher conductivity zone. Therefore, proposed test boring #1 is located approximately halfway between TW4-4 and TW4-6; and proposed test boring #2 is located approximately halfway between test boring #1 and TW4-4. Proposed locations #1 or #2 would be the most desirable for a new pumping well assuming the higher conductivity zone extends to the south of TW4-4 and is penetrated by one of these borings. Under conditions where, based on drilling, the higher conductivity zone does not appear to extend to the south of TW4-4 (is not penetrated by either test boring #1 or #2), test borings #3 and #4 are proposed immediately east and immediately west (within approximately 30 feet) of TW4-4. Test borings #3 and #4 are an attempt to penetrate the higher conductivity zone near TW4-4 assuming it has sufficient width. Under conditions where none of proposed test borings #1 through #4 encounter higher conductivity materials, test boring #5 will be installed immediately to the north (within approximately 30 feet) of TW4-4 as shown in Figure 2. The test boring having the highest productivity, based on water produced during drilling, will be overdrilled and completed as new pumping well TW4-41. If the higher conductivity zone is encountered by either test boring #1 or #2, a decision may be made to complete the most productive as TW4-41 and to terminate the installation of additional test borings. The new well will be completed within a larger diameter boring (nominal 10-inch diameter) and have a larger diameter casing (nominal 6-inch diameter) than TW4-4 (nominal 6 % inch diameter boring and 4-inch diameter casing). Test borings not completed as the new pumping well will be abandoned in accordance with State of Utah Administrative Rules for Water Wells R655-4-14. 4.1. Experts Reports to be Prepared As required by Part II.H.4) EFRI will submit an as-built report within 60 days of well installation for the newly installed wells proposed in this plan and time schedule. Boring logs for wells and test borings will be included in the as-built report. Assessment of the plume, hydraulic capture and effectiveness of the remediation strategy will be discussed in the quarterly chloroform reports submitted as required by the GCAP. 4.2. Time Schedule The installation of the proposed wells and the completion of the as-built reports will be completed in accordance with the required timeframes specified in the approved and executed GCAP. The proposed wells will be installed and operational within 90 days of director approval of this plan and time schedule and the as-built report will be completed within 60 days of well completion. 3 5. CONCLUSION The chloroform plume is currently entirely within the Mill property boundary and is bounded on all sides by wells having chloroform concentrations that are either non-detect or less than 70 pg/L. Data collected to date indicate there are sufficient chloroform monitoring and pumping wells to effectively define, control, and monitor the plume. Chloroform pumping as of the third quarter of 2017 (4.8 gpm) exceeds calculated ‘background’ flow through the plume (3.4 gpm) and is therefore considered adequate. In addition, because of continued reductions in saturated thicknesses and hydraulic gradients resulting from reduced wildlife pond recharge, ‘background’ flow through the plume is expected to continue to diminish, thereby reducing the pumping needed to control the plume. As previously stated, decreasing water level trends (since about the fourth quarter of 2013), and increasing concentration trends at TW4-26 are consistent with reduced wildlife pond seepage, in particular, reduced seepage from the southern wildlife pond. As the groundwater mound associated with the southern pond decays, groundwater flow directions in the southern extremity of the plume are likely to become more southerly, and plume migration is likely to turn more to the south. An increasingly southerly direction of plume migration is consistent with increasing concentrations at TW4-26. Proposed new compliance monitoring well TW4-40, located approximately 200 feet south of TW4-26 as shown in Figure 2, will be positioned cross-to downgradient of TW4-26. Because of groundwater flow directions that are increasingly southerly in this area, new well TW4-40 is expected to become increasingly downgradient rather than cross-gradient with respect to TW4- 26. Additional pumping within higher conductivity portions of the southern portion of the plume in the vicinity of existing pumping well TW4-4 is expected to result in a substantial increase in chloroform mass removal rates and to help cut off chloroform transport to more downgradient portions of the plume. As discussed above, small-diameter pilot holes are proposed to be drilled as shown in Figure 2 to ensure that new pumping well TW4-41 is located within a relatively high conductivity zone and will be productive. The most productive of the test borings will be reamed and completed as the new pumping well, which will have a nominal bore diameter of 10 inches and a casing diameter of 6 inches. Pumping in this area is expected to enhance mass removal rates and reduce or halt further plume expansion to the south. 4 FIGURES WM abandoned TWN-11 abandoned TWN-12 ms TWN-19 WBm : .. • ?mm> v _ . abandoned TWN-15 rii! TWN-16 /abandoned TWN-17 '• ."*« V- :/ f TWN-14 ND 2Q MW-01 abandoned TWN-10 ND 2Q. MW-18 abandoned TWN-05 .........I...: ■ • ' -• ' '■ ' ■■ ■'”1 s . 'NS TWN-06 abandoned TWN-08 abandoned TWN-09 .iliandoiied TWN-13 Js, PIEZ4J1 ND 20 MW-19 : ' •• .•■'-..V.'v'■■ ■ !. -v- -.■’>••V. V-vAc^ . -r .■ ••• -.f.' . ‘y ' ;■t / V-^£s$£v'>; ^ ndSs1 tiVr "•r!»V r ■; ND ZND.2Q MVV-24 MW4J2 Cell 1 ■V. ' ;V - -V MW-28 5150 O 027 ™4-39 ™4-°5 ™45M0™4-2° S TW4-38 MW2&D30 ™ * D TW4'12MVv-260 l3t0o o1 TW4-10l<‘IW4-03 oND \ ^ ......... ™o-16 TVM-13 Cell 2 ■ ■ .te MW-32' ~ TW4-04O1290 TW^™«2 ' - ' .. vi^ ®8 aTW4-36 TW4-14 06TW4416 TW4.26? i TW4-2|o ^440 QTW4-35 NDoTW4-34 Q .'I'' IF ISM' ' .. . ..•%;V .v:: * . . * -V :W; fe't- ■' it ! ' 'i ••. «’ > • : ... #■ ND2Q MW-3A dry MW-21 4 ; t M mix ■ ND 20 ■ MW-20 t , EXPLANATION NS = not sampled; ND = not detected; ND Q2 = not detected in second quarter "70 kriged chloroform isocon and label TW4-38 temporary perched monitoring well and installed October, 2016 showing concentration in pg/L PlycN3<f May’ 2016 replacement of perched & N '' piezometer Piez-03 (not sampled) ND2Q MW-22 1 mile MW-32• ND TW4-7O1070 TWN-1^NS PIEZ-1 ©NS perched monitoring well showing concentration in pg/L temporary perched monitoring well showing concentration in pg/L temporary perched nitrate monitoring well (not sampled) perched piezometer (not sampled) NOTES: MW-4, MW-26, TW4-1, TW4-2, TW4-4, TW4-11, TW4-19, TW4-20, TW4-21, TW4-37 and TW4-39 are chloroform pumping wells; TW4-22, TW4-24, TW4-25 and TWN-2 are nitrate pumping wells; HYDRO GEO CHEM, INC. KRIGED 3rd QUARTER, 2017 CHLOROFORM (|jg/L) WHITE MESA SITE DATE REFERENCE FIGURE H:/718000/tw40/Plan/Uchl0917.srf 1 TW4-38+ PIEZ-3A w MW-25 TW4-7 o PIEZ-2 O proposed test boring and sequence temporary perched monitoring well installed October, 2016 May, 2016 replacement of perched piezometer Piez-03 perched monitoring well temporary perched monitoring well perched piezometer NOTES: MW-4, MW-26, TW4-1, TW4-2, TW4-4, TW4-11, TW4-19, TW4-20, TW4-21, TW4-37 and TW4-39 are chloroform pumping wells; TW4-22, TW4-24, TW4-25 and TWN-2 are nitrate pumping wells; TW4-11 water level is below the base of the Burro Canyon Formation HYDRO GEO CHEM, INC. PROPOSED LOCATIONS OF NEW TEMPORARY COMPLIANCE WELL TW4-40 AND TEST BORINGS (one test boring to be completed as new DATE REFERENCE FIGURE H:/718000/tw40/Plan/propboringtw40.srf 2