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HomeMy WebLinkAboutDRC-2021-006812 - 0901a06880e8eb8cENERGY FUELS May 11, 2021 Sent VIA E-MAIL AND EXPRESS DELIVERY Jalynn Knudsen Interim Director Waste Management and Radiation Control State of Utah Department of Environmental Quality 195 North 1950 West Salt Lake City, UT 84116 Energy Fuels Resources (USA) Inc. 225 Union Blvd. Suite 600 Lakewood, CO, US, 80228 303 974 2140 www.energyfuels.com 2021 -12368- I 2_ Div of and Radiation Control MAY 1 3 2021 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 Ms. Knudsen: 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-29 for the first 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 or appropriate in light of other actions currently being undertaken by EFRI or in light of other reports submitted by EFRI. This Plan covers uranium in MW-29 that was identified as being in violation of Part I.G.2 of the Permit, in the First Quarter 2021 Exceedance Notice, dated April 23, 2021. Please contact me if you have any questions or require any further information. Yours very truly, ENERGY FUELS RESOURCES (USA) INC. ItriLa Kathy Weinel Quality Assurance Manager cc: Scott Bakken David Frydenlund Garrin Palmer Logan Shumway Terry Slade 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-29 in the First Quarter of 2021 Energy Fuels Resources (USA) Inc. 225 Union Boulevard, Suite 600 Lakewood, CO 80228 May 11, 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 ("P&TS") required under Part I.G.4(c) of the Permit relating to violations of Part I.G.2 of the Permit for MW-29 for the first 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. While consecutive exceedance have been noted in other wells at the site, 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. Additionally, pH was addressed in reports dated November 9, 2012 and December 7, 2012. 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. As discussed in previous quarterly groundwater sampling reports, the background levels and GWCLs for pH were established based on eight or more quarters of laboratory data, which are historically higher than field data. EFRI' s letter to the Director dated January 31, 2011 proposed the recalculation of the GWCLs for field pH. Following the statistical evaluation of pH data by EFRI' s geochemical consultant, INTERA, Inc., EFRI compared the Mill's groundwater pH data from Q2 2011 and noted that all of the June 2011 groundwater results, and many of the other results from Q2 2011, were already outside the revised GWCLs that were to be proposed in the June 30, 2011 letter. Pursuant to teleconferences with DWMRC on December 5, and December 19, 2011, EFRI submitted a Work Plan and Schedule on January 20, 2012 and a revised plan based on DWMRC comments on April 13, 2012. Based on the approved Work Plan and Time Schedule, EFRI and DWMRC entered into a Stipulated Consent Agreement ("SCA") dated July 12, 2012. The SCA required the completion of the pH Report and the Pyrite Investigation and associated report. The pH Report and Pyrite Investigation Report were submitted November 9, 2012 and December 7, 2012 respectively. By letter dated April 25, 2013, DWMRC accepted the conclusions that the out-of-compliance results for pH are due to background effects within the aquifer matrix and are not caused by Mill activities. DWMRC also approved the recalculation of the GWCLs. As a result, the 30-day plan and schedule for assessment is not required for field pH exceedances. 3. 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 19, 2019, because the conclusions and actions delineated in those reports were accepted by DWMRC. 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 Revised Background Groundwater Quality Report (INTERA, 2007a) and the New Wells Background Report (NTERA, 2008) (collectively with INTERA, 2007b, the "Background Reports"), the pH Report (INTERA, 2012), an isotopic investigation (Hurst and Solomon, 2008), a report discussing the occurrence and likely impact of naturally-occurring pyrite on perched (shallow) groundwater (the Pyrite Report [HGC, 2012a]), 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 P&TS covers uranium in MW-29, identified as being in violation of Part I.G.2 of the Permit, in the First Quarter 2021 Exceedance Notice, dated April 23, 2021. 2. CONSTITUENTS AND WELLS SUBJECT TO THIS PLAN The following constituents are covered by this P&TS: Table 1 Constituents and Wells Subject to this Plan Constituent POC Well GWCL (N/L) Q4 2020 and Q1 2021 Results (ttg/L) Uranium MW-29 15 15.3, 16.9 It should be noted that the First Quarter 2021 Exceedance Notice identifies a number of wells with consecutive exceedances of other constituents that are not included in this P&TS, for the reasons stated in Section 1 above and in the First Quarter 2021 Exceedance Notice. This P&TS is being submitted to DWMRC by EFRI to address exceedances in MW-29 for uranium. 3. CATEGORIES FOR ANALYSIS EFRI has previously categorized wells and constituents in several categories as follows: • Constituents Potentially Impacted by Decreasing pH Trends Across the Site • Newly Installed Wells with Interim GWCLs • Constituents in Wells with Previously Identified Rising Trends • Pumping Wells • Other Constituents and Wells Uranium in MW-29 falls within the third category: Constituents in Wells with Previously Identified Rising Trends. Uranium concentrations in MW-29 have been increasing since the well was installed in 2006. Trends in uranium concentrations in MW-29 were observed in the 2008 New Wells Background Report, the pH report submitted to DWMRC on November 9, 2012, and the 2013 SAR for Total Dissolved Solids ("TDS") in MW-29. It is important to note that the initial GWCL for uranium in MW-29 was set using the minimum eight data points and does not accurately reflect the true natural variation that would be evident with a larger data set. There are now 40 data points available, which will undoubtedly affect the outcome of the analysis. Assessment of uranium in MW-29 will follow the process noted below. 3.1. Constituents in Wells with Previously Identified Rising Trends Uranium concentrations in MW-29 exhibit a statistically significant upward trend first identified during the 2012 pH Report (Intera 2012). Preliminary analysis of pH and the indicator parameters shows that pH and chloride are stable and fluoride and sulfate in MW-29 are exhibiting downward trends. As discussed in previous reports, the absence of increasing concentrations of indicator parameters indicates there is no potential TMS seepage. Water level behavior at MW-29 is important when assessing potential sources of contamination. The water level in MW-29 has increased since 2006 due to perched water mounding associated with the northern wildlife ponds. Although use of the northern ponds was discontinued in March 2012, and the central portion of the mound has diminished, this mound is still evident as water levels have not returned to pre-pond conditions; therefore the mound is still expanding and causing increases in water levels at relatively distant wells such as MW-29. Increasing constituent concentrations in many wells (such as MW-29) are attributable to water level changes caused by the associated groundwater mound. EFRI and its consultants anticipated these changes and discussed these and other potential effects during discussions with DWMRC in March 2012 and May 2013. The transient nature of a large portion of the perched water system at the Mill, manifested in long-term changes in saturated thicknesses and rates of groundwater flow, is expected to result in trends in the concentrations of many dissolved constituents that are unrelated to site operations. Changes in saturated thicknesses and rates of groundwater flow can result in changes in concentrations of dissolved constituents for many reasons. For example, as discussed in HGC (2012), groundwater rising into a vadose zone having a different chemistry than the saturated zone can result in changes in pH and groundwater constituent concentrations. If the rise in groundwater represents a long-term trend, long-term changes in groundwater constituent concentrations may result. Furthermore, if water level changes at MW-29 were the result of TMS seepage, concentrations of conservative constituents such as chloride would be orders of magnitude larger than measured. For example, the saturated thickness at MW-29 has increased from approximately 20 to 25 feet. Assuming this change was caused by mixing TMS solution into the groundwater, the result would be a solution consisting of approximately 80% groundwater and 20% TMS solution, yielding a chloride concentration of thousands of mg/L rather the measured concentration of less than 40 mg/L. 4. PLAN 4.1. General This is 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 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 analyses in the Background Reports, SARs, pH Report, and Pyrite Report and other recent information relating to the Chloroform and Nitrate/Chloride investigations at the site, EFRI believes that all of the exceedances are likely due to background influences (including a natural decreasing trend in pH across the site [evident until approximately 2016, when pH in most wells began to stabilize or trend upward], 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. 4.2. Constituents in Wells with Previously Identified Rising Trends The primary focus of a source assessment for uranium in MW-29 is to determine whether or not there is any new information that would suggest that the previous analysis conducted in the New Wells Background Report, pH Report and Pyrite Report has changed since the date of those Reports. Preliminary analysis of pH and the indicator parameters shows that pH and chloride are stable and fluoride and sulfate in MW-29 are exhibiting downward trends. As discussed in previous reports, the absence of increasing trend in indicator parameters indicates there is no potential TMS impacts. The initial GWCL for uranium in MW-29 was set using the minimum eight data points and does not accurately reflect the true natural variation that would be evident with a larger data set. There are now 40 data points available, which will undoubtedly affect the outcome of the analysis. Therefore, EFRI will continue accelerated monitoring for uranium in MW-29 while EFRI prepares, and the Director evaluates, a SAR which will include a geochemical analysis of uranium and indicator parameters in MW-29, and if appropriate, a proposed revised GWCL using all data available at the time of the analysis. The revised GWCL process will include a statistical analysis of uranium data from MW-29 using the methods described in the Existing Wells Background Report (INTERA, 2007a) and the State of Utah Department of Environmental Quality approved Flowsheet ("the Flowsheet"). 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 Unified Guidance, Environmental Protection Agency, Office Of Resource Conservation And Recovery.) 4.3. Expert Reports to be Prepared The results of the statistical analysis and, if appropriate, recalculation of the GWCLs 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 of the analyses performed and the conclusions drawn from such analyses, including any proposed revisions to existing GWCLs. Specifically, the SAR will follow the format of the previously submitted SARs and will include discussions, results and conclusions of the analyses and appendices containing the following: A statistical analysis of SAR parameters in MW-29 to support a geochemical evaluation 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 Proposed Revised GWCLs for MW-29 A statistical analysis of Indicator Parameters in MW-29 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 for MW-29 will be submitted to the Director within 90 days after approval of this P&TS. The SAR contemplated by this submission may be combined with any subsequent SARs resulting from other P&TSs 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. Increasing concentrations of uranium in MW-29 are not associated with increasing concentrations of TMS indicator parameters. Concentrations of fluoride and sulfate are decreasing and pH and chloride in MW-29 are stable and exhibit no trend. The absence of increasing trends in indicator parameters indicates there is no potential TMS seepage. Current conditions within the perched groundwater system hosted by the Burro Canyon Formation and Dakota Sandstone do not approach steady state over much of the monitored area. A large part of the site perched water system is transient and affected by long-term changes in water levels due to past and current activities unrelated to the disposal of materials to the site TMS. Changes in water levels have historically been related to seepage from the wildlife ponds; however past impacts related to the historical pond are also expected. The water level in MW-29 has increased since 2006 due to perched water mounding associated with the wildlife ponds, which is still evident. Since use of the northern ponds was discontinued in March 2012, increases in constituent concentrations have been noted in many wells, and is attributable (at least in part) to the water level changes resulting from the associated groundwater mound. Concentrations of indicator parameters fluoride and sulfate are decreasing and pH and chloride in MW-29 are stable and exhibit no trend indicating there is no potential TMS seepage. Furthermore, if water level changes at MW-29 were the result of TMS seepage, concentrations of conservative constituents such as chloride would be orders of magnitude larger than measured.