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HomeMy WebLinkAboutDRC-2021-012229 - 0901a06880f3f91eDiv or and RacLation Control AUG 2 7 2021 ENERGYFUELS Energy Fuels Resources (USA) Inc. 225 Union Blvd. Suite 600 Lakewood, CO, US, 80228 303 974 2140 www.energyfuels.com August 25, 2021 Sent VIA E-MAIL AND EXPRESS DELIVERY Doug Hansen, Director of Waste Management and Radiation Control State of Utah Department of Environmental Quality 195 North 1950 West Salt Lake City, UT 84116 PRC-2o21-012229 Re: Transmittal of Plan and Time Schedule under Utah Ground Water Discharge Permit UGW370004 Part I.G.4 (c) White Mesa Mill (the "Mill") Dear Mr. Hansen: This letter transmits Energy Fuels Resources (USA) Inc.' s ("EFRI' s") Plan and Time Schedule pursuant to State of Utah Groundwater Discharge Permit UGW370004 (the "Permit") Part I.G.4(c) for MW-30 for the second quarter of 2021. Part I.G.2 of the Permit provides that out-of-compliance ("00C") status exists when the concentration of a pollutant in two consecutive samples from a compliance monitoring point exceeds a groundwater compliance limit ("GWCL"). While consecutive exceedance have been noted in other wells at the site, a plan and time schedule have not been required for those constituents in light of other actions currently being undertaken by EFRI or in light of other reports submitted by EFRI. This Plan covers uranium and selenium in MW-30 that was identified as being in violation of Part I.G.2 of the Permit, in the Second Quarter 2021 Exceedance Notice, dated July 28, 2021. Please contact me if you have any questions or require any further information. Yours very truly, ENERGY FUELS RESOURCES (USA) INC. Is'tbety Kathy Weinel Quality Assurance Manager cc: Scott Bakken David Frydenlund Garrin Palmer Logan Shumway Angie Persico (INTERA) Stewart Smith (HGC) WHITE MESA MILL State of Utah Ground Water Discharge Permit UGW370004 Plan and Time Schedule Under Part I.G.4 (c) For Exceedances in MW-30 in the Second Quarter of 2021 Energy Fuels Resources (USA) Inc. 225 Union Boulevard, Suite 600 Lakewood, CO 80228 August 25, 2021 1. INTRODUCTION Energy Fuels Resources (USA) Inc. ("EFRI") operates the White Mesa Uranium Mill (the "Mill"), located near Blanding Utah, under State of Utah Ground Water Discharge Permit UGW370004 (the "Permit"). This is the plan and time schedule (the "Plan") required under Part I.G.4(c) of the Permit relating to violations of Part I.G.2 of the Permit for the MW-30 for the second quarter of 2021. Part I.G.2 of the Permit provides that out-of-compliance status exists when the concentration of a pollutant in two consecutive samples from a compliance monitoring point exceeds a groundwater compliance limit ("GWCL") in Table 2 of the Permit. Uranium and selenium concentrations in MW-30 exceeded their respective GWCLs during the second quarter of 2021 and are the subject of this Plan. While consecutive exceedances of other constituents have been noted in MW-30, a P&TS and Source Assessment Report ("SAR") have not been required or appropriate in light of other actions currently being undertaken by EFRI or in light of other reports submitted by EFRI, and as determined by Division of Waste Management and Radiation Control ("DWMRC") Staff. Specifically, consecutive exceedances, which occurred in previous reporting periods are discussed in previous SARs submitted to DWMRC. A description of the other actions and reports which have affected the requirement to submit a P&TS are as follows: 1. Nitrate + nitrite and chloride in monitoring wells at the site have been the subject of ongoing investigations at the Mill. Based on the results of the previous investigations, EFRI and the Director acknowledge that it has not been possible to date to determine the source(s), cause(s), attribution, magnitudes of contribution, and proportion(s) of the local nitrate + nitrite and chloride in groundwater. However, as the commingled nitrate and chloride plumes (collectively the nitrate/chloride plume) extended upgradient of the tailings management system ("TMS"), it can be concluded that at least the northern portion of the plume had an upgradient source. EFRI submitted a Corrective Action Plan ("CAP") in February 2012 for nitrate + nitrite and chloride in groundwater. The CAP was approved on December 12, 2012 and the activities associated with the CAP are on- going. Based on information provided by DWMRC in teleconferences on April 27, and May 2, 2011, due to the ongoing activities and actions, the 30-day plan and schedule for assessment is not required for nitrate + nitrite and chloride exceedances at this time. 2. A P&TS will not be prepared for monitoring wells with two successive exceedances, if those successive exceedances were reported in a previous quarter and /or were included in a previous SAR during the current permit period beginning March 8, 2021, because the conclusions and actions delineated in those reports were accepted by DWMRC. 3. A chloroform plume commingles with the central portion of the nitrate/chloride plume. Chloroform and associated daughter product methylene chloride are the subject of the ongoing chloroform pumping program and are covered by State of Utah Notice of Violation ("NOV") and Groundwater Corrective Action Order ("CAO") State of Utah Department of Environmental Quality ("UDEQ") Docket No. UGW-20-01. As a result, the 30-day plan and schedule for assessment of chloroform and its daughter product exceedances is not required. Groundwater at the Mill site has been evaluated in multiple recent investigations and reports, including the 2007 Revised Background Groundwater Quality Report and the 2008 New Wells Background Report, an isotopic investigation performed by Hurst and Solomon in 2008, the 2012 Pyrite Report, and multiple SARs. Based on a review of the Background Reports and other information and analyses the Director re-opened the Permit and modified the GWCLs to be equal to the mean concentration plus two standard deviations or the equivalent of background for each constituent on an intrawell basis. The modified GWCLs became effective on January 20, 2010. A new GWDP was issued on January 19, 2018. The January 19, 2018 GWDP incorporated the revised GWCLs that resulted from previous SARs. Revised GWDPs were issued on March 19, 2019 and March 8, 2021. The revised GWDPs incorporated the revised GWCLs that resulted from previous SARs among other changes. Part I.G.4 c) of the GWDP states, with respect to exceedances of GWCLs, "that the Permittee shall prepare and submit within 30 calendar days to the Executive Secretary a P&TS for assessment of the sources, extent and potential dispersion of the contamination, and an evaluation of potential remedial action to restore and maintain groundwater quality to insure that Permit limits will not be exceeded at the compliance monitoring point and that DMT or BAT will be reestablished." Pursuant to this requirement, EFRI has previously submitted P&TSs and SARs to address previous dual exceedances (as required in light of other actions currently being undertaken by EFRI and as determined by DWMRC Staff and stated in teleconferences with EFRI on April 27 and May 2, 2011). This Plan covers uranium and selenium in MW-30, identified as being in violation of Part I.G.2 of the Permit, in the Second Quarter 2021 Exceedance Notice, dated July 28, 2021. 2. CONSTITUENTS AND WELLS SUBJECT TO THIS PLAN The following constituents are covered by this Plan: Table 1 Constituent and Well Subject to this Plan Constituent POC Well Current GWCL Q2 2021 Results Selenium (ug/L) MW-30 53.6 55.7, 58.3, 54.1 Uranium (ug/L) MW-30 9.82 10.3, 10.7, 9.84 It should be noted that the second quarter 2021 Exceedance Notice identifies a number of wells, with consecutive exceedances of other constituents. None of those constituents are included in this Plan, for the reasons stated in Section 1 above and in the Second Quarter Exceedance Notice. This Plan and the subsequent SAR are being submitted to DWMRC by EFRI to address exceedances in MW-30 for uranium and for selenium which were addressed in previous a SAR, but have exceeded the GWCLs specified in the March 8, 2021 GWDP due to statistically significant trends noted in previous studies. Nitrate + Nitrite and Chloride concentrations in MW-30 are associated with the Nitrate/Chloride plume, and are currently covered by the December 12, 2012 Stipulation and Consent Order. 3. CATEGORIES FOR ANALYSIS Previously EFRI has categorized wells and constituents in several categories as follows: 1. Constituents Potentially Impacted by Decreasing pH Trends Across the Site 2. Newly Installed Wells with Interim GWCLs 3. Constituents in Wells with Previously Identified Rising Trends 4. Pumping Wells 5. Other Constituents Uranium and selenium in MW-30 fall within the third category: Constituents in Wells with Previously Identified Rising Trends. Assessment of these constituents in MW-30 will follow the process noted below with additional considerations to address the previously identified rising trends. 3.1. Constituents in Wells with Previously Identified Rising Trends Uranium and selenium concentrations in MW-30 were exhibiting increasing trends at the time of the Background Report, although the trends were not statistically significant. Selenium and uranium were addressed in previous SARs but have exceeded the most recent recalculated GWCL specified in the March 8, 2021 GWDP due to statistically significant trends noted in these previous studies. The location of MW-30 is important when determining potential sources of contamination. MW-30 was included in the October 2012 SAR and in the January 15, 2019 SAR for exceedances of selenium and selenium, uranium and pH respectively. The previous SARs concluded that the increasing concentrations of indicator parameter, chloride, was due to the proximity of that well to the nitrate/chloride plume. MW-30 is located within the downgradient (southern) margin of the nitrate/chloride plume. The nitrate/chloride plume has been the subject of many studies that are described in detail in the following reports: • Nitrate Contamination Investigation Report • Quarterly Nitrate Reports 2009-2021 The nitrate/chloride plume is currently being addressed by the ongoing activities under the DWMRC-approved CAP. Other factors to consider in the evaluation of MW-30 include the following: 1) Concentration of indicator parameters fluoride and sulfate are and stable to decreasing. 2) Although nitrate at MW-30 has been relatively stable since 2012, nitrate has increased since installation in 2005. The increase in nitrate correlates to increases in both selenium and uranium concentrations exceeding the GWCL. Both uranium and selenium increases may result from nitrate oxidizing and mobilizing naturally-occurring uranium and selenium; or uranium and selenium that may be generally elevated in the nitrate/chloride plume due to the historical pond having seeped through the Mancos Shale (a source of both uranium and selenium) is now migrating past MW-30; or both uranium and selenium may be released from pyrite oxidized by nitrate or from elevated dissolved oxygen ("DO") in the plume. 4. PLAN 4.1. General This Plan is a plan and time schedule for assessment of the sources, extent and potential dispersion of the contamination, and an evaluation of potential remedial action to restore and maintain groundwater quality to ensure that Permit limits will not be exceeded at the compliance monitoring point and that, to the extent applicable, discharge minimization technology and best available technology will be reestablished. Given the recent site-wide analyses in the Background Reports, SARs, and Pyrite Report and other recent information relating to the Chloroform and Nitrate/Chloride investigations at the site, EFRI believes that exceedances in MW-30 are likely due to background influences (including changing water levels in some wells and other factors), disruption of the aquifer by pumping, and/or the geochemical influences of the existing chloroform and nitrate/chloride plumes. Therefore, the first step in the analysis will be to perform an assessment of the potential sources for each exceedance to determine whether the exceedance is due to background influences or Mill activities. If an exceedance is determined to be due to background influences then it will not be necessary to perform any further evaluations on the extent and potential dispersion of the contamination or to perform an evaluation of potential remedial actions. Monitoring will continue, and where appropriate revised GWCLs will be proposed to reflect changes in background conditions at the site. However, if any of the exceedances are determined to be caused by Mill activities, then EFRI will proceed to the next step and will consider the extent and potential dispersion of the contamination, and will perform an evaluation of potential remedial actions to restore and maintain groundwater quality to ensure that Permit limits will not be exceeded at the compliance monitoring point. This two-step approach is necessary, because, in light of the varied background conditions at the site, it can't be assumed that consecutive exceedances of a constituent in a well represents contamination that has been introduced to the groundwater. It is first necessary to establish whether or not the exceedances represent background influences. 4.2. Constituents With Pre-Existing Rising Trends It was well known at the time of setting the current GWCLs that certain constituents had rising trends. On page 3 of the Existing Well Background Report, INTERA concluded: "There are numerous cases of both increasing and decreasing trends in constituents in upgradient, far downgradient, and Mill site wells, which provide evidence that there are natural forces at work that are impacting groundwater quality across the entire site. In almost all cases where there are increasing trends in constituents in wells at the site, there are increasing trends in those constituents in upgradent wells. Furthermore, and more importantly, in no case is there any evidence in the wells in question of increasing trends in chloride, which is considered the most mobile and best indicator of potential tailings cell leakage at the site. We consider the combination of these factors to be conclusive evidence that all increasing trends at the site are caused by natural forces and not by Mill activities". The Groundwater Data Preparation and Statistical Process Flow for Calculating Groundwater Protection Standards, White Mesa Mill Site, San Juan County, Utah, (the "Flowsheet") which was approved by the Director, states in the final decision box, for circumstances where the data indicate an increasing trend to consider a modified approach to GWCLs. If necessary, a modified approach may be submitted as part of the SAR. The revised GWCL process will include a statistical analysis of uranium and selenium data from MW-30 using the methods described in the approved Flowsheet. As mentioned in previous SARs, the United States Environmental Protection Agency ("EPA") has recognized the need to update compliance limits periodically to reflect changes to background conditions. In 2009 guidance, EPA states: "We recommend that other reviews of background also take place periodically. These include the following situations: • When periodically updating background, say every 1-2 years • When performing a 5-10 year permit review During these reviews, all observations designated as background should be evaluated to ensure that they still adequately reflect current natural or baseline groundwater conditions. In particular, the background samples should be investigated for apparent trends or outliers. Statistical outliers may need to be removed, especially if an error or discrepancy can be identified, so that subsequent compliance tests can be improved. If trends are indicated, a change in the statistical method or approach may be warranted." and "Site-wide changes in the underlying aquifer should be identifiable as similar trends in both upgradient and compliance wells. In this case, it might be possible to remove a common trend from both the background and compliance point wells and to perform interwell testing on the trend residuals." (EPA 530/R-09-007, March 2009, Statistical Analysis Of Groundwater Monitoring Data At RCRA Facilities Wied Guidance, Environmental Protection Agency, Office Of Resource Conservation And Recovery.) 4.3. Experts Reports to be Prepared The results of the statistical analysis and, if appropriate, recalculation of the GWCL will be compiled as a SAR that will be submitted to DWMRC within 90 days of the approval of this Plan. The SAR will detail the results of all analyses to be performed and the conclusions to be drawn from such analyses, including proposed revision to the existing GWCL. Specifically, the SAR will follow the format of the originally submitted SAR (October 10, 2012) and will include discussions, results and conclusions of the analyses and appendices containing the following: A Statistical analysis of SAR Parameters Comparison of calculated and measured TDS for samples with complete major ions Charge balance calculations Descriptive statistics Box plots to identify extreme outliers Histograms and Shapiro Wilk test for normality Regression or Mann Kendall trend analysis Evaluation of inflection points and data subsets Proposed Revised GWCLs A statistical analysis of Indicator Parameters Descriptive Statistics Box plots to identify extreme outliers Histograms and Shapiro Wilk test for normality Regression and/or Mann Kendall trend analysis 5. TIME SCHEDULE The SAR will be submitted to the Director within 90 days after approval of this Plan. The SAR contemplated by this submission, may be combined with any subsequent SARs resulting from other Plans and Schedules for other out of compliance constituents, as necessary. 6. CONCLUSION Given the varied background groundwater quality at the site it cannot be assumed that consecutive exceedances of a constituent in a monitoring well means that contamination has been introduced to groundwater in that well. The location of MW-30 is important when determining potential sources of contamination. The concentrations of many constituents in MW-30 were due to or affected by the proximity of that well to the nitrate/chloride plume. MW-30 is located within the leading edge of the nitrate and chloride plume and is generally downgradient of the historical pond, the likely source of the commingled nitrate and chloride plumes (collectively the N/C1 plume). Chloride and nitrate at MW-30 has been generally increasing at least since 2009. The nitrate/chloride plume has been the subject of many studies that are described in detail in separate reports. Concentration of indicator parameters fluoride and sulfate are stable to decreasing. Although nitrate at MW-30 has been relatively stable since 2012, nitrate has increased since installation in 2005. The increase in nitrate correlates to increases in selenium and uranium. Nitrate may be oxidizing and mobilizing naturally-occurring uranium and selenium; or uranium and selenium that may be generally elevated in the nitrate/chloride plume due to the historical pond having seeped through the Mancos Shale is now migrating past MW-30; or uranium and selenium may be released from pyrite oxidized by nitrate or from elevated DO in the plume. The relative stability of the downgradient (southern) margin of the nitrate component of the nitrate/chloride plume implies a degradation mechanism that affects nitrate but not chloride; the most likely mechanism is degradation (reduction) of nitrate by naturally-occurring pyrite in the formations hosting perched groundwater at the site. Because pyrite may contain both uranium and selenium as contaminants, both may be released upon reaction of pyrite with nitrate.