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Home My WebLink AboutDRC-2020-003725 - 0901a06880bf7e1aFebruary 19, 2020 ENERGY FUELS Energy Fuels Resources (USA) Inc. 225 Union Blvd. Suite 600 Lakewood, CO, US, 80228 303 974 2140 D — ZOZo Oo3s7 2.5 www.enerofuels.com Sent VIA E-MAIL AND EXPRESS DELIVERY Mr. Ty L. Howard Director Division of Waste Management and Radiation Control Utah Department of Environmental Quality 195 North 1950 West P.O. Box 144880 Salt Lake City, UT 84114-4880 Div of Waste Management and Radiation Control FEB 2 I 2020 Re: Transmittal of White Mesa Uranium Mill Cell 2 Reclamation Cover 2019 Annual Performance Monitoring Report Dear Mr. Howard: In accordance with the Stipulation and Consent Agreement ("SCA" dated February 23, 2017) between the Division of Waste Management and Radiation Control ("DWMRC") and Energy Fuels Resource (USA) Inc. ("EFRI"), EFRI constructed a cover performance monitoring test section ("Primary Test Section") on Cell 2 in 2016, completed Phase 1 cover placement on Cell 2 in 2017, constructed a supplement vegetation monitoring test section ("Supplemental Test Section") in 2017, and initiated performance monitoring. This letter transmits the 2019 annual performance monitoring report for the reclamation cover and includes monitoring results for both test sections. This report is being provided to DWMRC for information only, as submittal of this report is not a requirernent of the SCA since the official test section monitoring tirne period has not yet started. For your convenience, two hard copies of the report and two CDs, each containing a word searchable electronic copy of the files, will be mailed to DWMRC. If you should have any questions regarding this transmittal please contact me at 303-389-4134. Yours very truly, ENERGY FUELS RESOURCES (USA) INC. Kathy Weinel Quality Assurance Manager CC- David Frydenlund Terry Slade Logan Shurn way Scott Bakken Paul Goranson February 19, 2020 Sent VIA E-MAIL AND EXPRESS DELIVERY Mr. Ty L. Howard Director Division of Waste Management and Radiation Control 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 .energyfuels.com Re: Transmittal of White Mesa Uranium Mill Cell 2 Reclamation Cover 2019 Annual Performance Monitoring Report Dear Mr. Howard: In accordance with the Stipulation and Consent Agreement ("SCA" dated February 23, 2017) between the Division of Waste Management and Radiation Control ("DWMRC") and Energy Fuels Resource (USA) Inc. ("EFRI"), EFRI constructed a cover performance monitoring test section ("Primary Test Section") on Cell 2 in 2016, completed Phase 1 cover placement on Cell 2 in 2017, constructed a supplement vegetation monitoring test section ("Supplemental Test Section") in 2017, and initiated performance monitoring. This letter transmits the 2019 annual performance monitoring report for the reclamation cover and includes monitoring results for both test sections. This report is being provided to DWMRC for information only, as submittal of this report is not a requirement of the SCA since the official test section monitoring time period has not yet started. For your convenience, two hard copies of the report and two CDs, each containing a word searchable electronic copy of the files, will be mailed to DWMRC. If you should have any questions regarding this transmittal please contact me at 303-389-4134. �;;;ru ENERGY FUELS RESOURCES (USA) INC.Kathy Weinel Quality Assurance Manager CC: David Frydenlund Terry Slade Logan Shumway Scott Bakken Paul Goranson White Mesa Uranium Mill Cell 2 Reclamation Cover 2019 Annual Performance Monitoring Report February 14, 2020 Prepared for: Energy Fuels Resources (USA) Inc. Prepared by: Stantec Consulting Services Inc. ~ Stantec Document Review and Revision Record Rev. Description Author(s) Quality Check Independent Review 0 Draft for client review S. Downey, C. Benson, J. Dillon 1/31/2020 M. Davis 2/4/2020 C. Strachan 2/6/2020 WHITE MESA URANIUM MILL CELL 2 RECLAMATION COVER 2019 ANNUAL PERFORMANCE MONITORING REPORT Table of Contents 1.0 INTRODUCTION .......................................................................................................... 1.1 1.1 BACKGROUND ............................................................................................................ 1.1 1.2 MONITORING REQUIREMENTS ................................................................................. 1.2 1.3 REPORT ORGANIZATION .......................................................................................... 1.3 2.0 COVER AND PRIMARY TEST SECTION DESIGN ..................................................... 2.1 3.0 PRIMARY TEST SECTION HYDROLOGIC MONITORING ......................................... 3.1 4.0 PRIMARY AND SUPPLEMENTAL TEST SECTIONS VEGETATION INSPECTION ............................................................................................................... 4.1 5.0 CELL 2 SETTLEMENT AND WATER LEVEL MONITORING...................................... 5.1 5.1 SETTLEMENT MONUMENTS...................................................................................... 5.1 5.2 PIEZOMETERS ............................................................................................................ 5.2 6.0 CONCLUSIONS ........................................................................................................... 6.1 7.0 REFERENCES ............................................................................................................. 7.1 LIST OF TABLES Table 1 Primary Test Section Water Balance for 2016 – 2019 Table 2 Cell 2 Top Surface Settlement Measured Between April 2016 and December 2019 Table 3 Piezometer Water Level Elevations During and After Phase 1 Cover Placement LIST OF FIGURES Figure 1 Regional Location Map Figure 2 Site Location Map Figure 3 Cover Profile within Lysimeter Figure 4 Settlement Monument and Piezometer Locations LIST OF APPENDICES APPENDIX A FIELD HYDROLOGY OF THE CELL 2 PRIMARY TEST SECTION AT THE WHITE MESA MILL APPENDIX B 2019 REVEGETATION EVALUATION CELL 2 PRIMARY AND SUPPLEMENTAL TEST SECTIONS APPENDIX C CELL 2 SETTLEMENT MONITORING DATA APPENDIX D CELL 2 STANDPIPE PIEZOMETER WATER LEVELS IJ WHITE MESA URANIUM MILL CELL 2 RECLAMATION COVER 2019 ANNUAL PERFORMANCE MONITORING REPORT Introduction 1.1 1.0 INTRODUCTION This report documents the 2019 monitoring and inspection results for the reclamation cover and Primary and Supplemental Test Sections on the Cell 2 tailings management cell at the Energy Fuels Resources (USA) Inc. (EFRI) White Mesa Uranium Mill site (Mill site). Reclamation cover performance monitoring for Cell 2 was initiated in 2016. Calibration monitoring was conducted from 2018 through 2019. This report is provided to the Utah Department of Environmental Quality, Division of Waste Management and Radiation Control (DWMRC) for information only. Official cover performance monitoring and required reporting began January 1, 2020. The Mill site is located in San Juan County in southeastern Utah, approximately 6 miles south of Blanding, Utah. Figure 1 shows a regional location map and Figure 2 shows the site layout. EFRI site facilities are within an approximately 686-acre restricted area and consist of a uranium processing mill and lined tailings management/evaporation ponds. 1.1 BACKGROUND On November 11, 2015, the DWMRC recommended that EFRI develop a plan to begin reclamation of Cell 2. This plan would consist of placing the proposed cover system presented in Reclamation Plan, Revision 5.1 (EFRI, 2016) on Cell 2 in two phases and demonstrating acceptable cover performance via a performance monitoring program. The Reclamation Plan was updated to Revision 5.1B (EFRI, 2018) on February 8, 2018. Information and requirements for the Cell 2 reclamation cover construction and monitoring did not change for Revision 5.1B. Thus, references to the Reclamation Plan in the remainder of this report refer to Revision 5.1B. EFRI and DWMRC executed a Stipulation and Consent Agreement (SCA) on February 23, 2017 defining the commitments and timeframes for completing placement of reclamation cover on Cell 2 and performance assessment of the cover system, in accordance with the Reclamation Plan. EFRI committed to the following tasks by the end of 2017: (1) completion of Phase 1 cover placement on Cell 2, (2) construction of a cover performance monitoring test section (Primary Test Section), and (3) construction of a supplemental vegetation monitoring test section (Supplemental Test Section). Cell 2 Phase 1 cover placement commenced in April 2016, was completed in April 2017, and is documented in Stantec (2017b). The Primary Test Section was constructed within the Cell 2 cover in fall 2016 (concurrently with the Phase 1 cover placement). The Primary Test Section construction was considered complete (per the DWMRC) after finalizing the laboratory testing for samples collected from the test section during construction and submitting the as-built report (June 30, 2017). Construction of this test section is documented in Stantec (2017a). The Supplemental Test Section was constructed in fall 2017 as a supplemental vegetation monitoring section to the Primary Test Section (Stantec, 2018a). The Supplemental Test Section does not evaluate the entire cover profile but will demonstrate that vegetation can be established and that erosional influences will not be detrimental to long-term vegetation establishment. The Supplemental Test Section 11 WHITE MESA URANIUM MILL CELL 2 RECLAMATION COVER 2019 ANNUAL PERFORMANCE MONITORING REPORT Introduction 1.2 was constructed in a location representative of cover conditions on the tailings management system cells (see Figure 2). The Supplemental Test Section is 100 feet by 100 feet in size to match the dimensions of the Primary Test Section. The slope of the test section is greater than 1 percent (the maximum reclamation cover slope). The cover design includes addition of gravel to the topsoil for slopes greater than 0.5 percent. However, gravel was not added to the topsoil for the test section to evaluate the short- term impact of erosion on the vegetative cover without gravel addition. Successful Supplemental Test Section performance will then translate to both the cover with or without the addition of gravel for erosion protection. Mulch was placed to provide erosion protection for the seeds during germination and early seedling growth. The Reclamation Plan (EFRI, 2018) provides additional design information for the Supplemental Test Section. 1.2 MONITORING REQUIREMENTS The Primary Test Section is required to be monitored for percolation and vegetative cover performance. Per the SCA, the Primary Test Section calibration monitoring was required to begin on January 1, 2018 (following Primary Test Section construction completion) and be conducted for two years. The calibration monitoring and results from 2017 and 2018 are in the 2017 and 2018 Annual Performance Monitoring Reports (Stantec, 2018b and Stantec, 2019, respectively). Official performance monitoring was required to commence two calendar years after calibration monitoring begins (i.e. January 1, 2020) and continue for five years. The Supplemental Test Section will be monitored annually for erosional stability and vegetative cover during official performance monitoring. Percolation monitoring procedures are outlined in the Reclamation Plan (EFRI, 2018). The percolation rate from the base of the lysimeter in the Primary Test Section will be used as the percolation performance parameter for the cover system. The cover design will be considered to have performed adequately if the average annual percolation rate is 2.3 mm/yr or less over the official performance monitoring time period. Vegetation sampling and monitoring procedures for the test section follow recommendations outlined in the Reclamation Plan (EFRI, 2018). The vegetation component of the cover will be considered successful if: (1) a minimum vegetation cover of 40 percent, and (2) acceptable vegetation diversity per EFRI (2018) (perennial grasses, forbs and shrubs) are met for the Supplemental and Primary Test Sections by the end of the five-year performance monitoring time period. As part of Cell 2 reclamation, EFRI is also conducting settlement monitoring of the Phase 1 cover surface and monitoring water levels in the Cell 2 using procedures outlined in the Reclamation Plan (EFRI, 2018). Monitoring results for settlement and water levels and interpretation of these results are included in this report. Settlement and dewatering data will be evaluated after completing the cover performance monitoring. The evaluation will determine if sufficient settlement has occurred to facilitate Phase 2 cover placement and minimize maintenance of the final cover surface. Per the SCA, decreasing trends in settlement followed by a maximum of 0.1 feet (30 mm) of cumulative settlement over 12 months (for at least 90 percent of the settlement monuments), will be considered acceptable to proceed with placement of the Phase 2 Cell 2 cover. 11 WHITE MESA URANIUM MILL CELL 2 RECLAMATION COVER 2019 ANNUAL PERFORMANCE MONITORING REPORT Introduction 1.3 During the official performance monitoring time period, EFRI is required to submit quarterly data quality reports and annual performance monitoring reports to DWMRC. EFRI has provided data quality reports to DWMRC for information purposes since mid-2017 and is providing this 2019 annual monitoring report for information purposes as well. Report submittals required for the official performance monitoring begin in 2020, with the 2020 First Quarter Data Quality Report being the first report required to be submitted (submittal due May 30, 2020). 1.3 REPORT ORGANIZATION This report provides an overview of the cover and Primary Test Section design (Section 2.0), Primary Test Section hydrologic monitoring (Section 3.0), Primary and Supplemental Test Section vegetation survey results (Section 4.0), Cell 2 settlement and water level monitoring (Section 5.0), and conclusions (Section 6.0). 11 WHITE MESA URANIUM MILL CELL 2 RECLAMATION COVER 2019 ANNUAL PERFORMANCE MONITORING REPORT Cover and Primary Test Section Design 2.1 2.0 COVER AND PRIMARY TEST SECTION DESIGN The cover system is a monolithic water balance cover, designed to minimize percolation, meet the radon emanation standard, and minimize maintenance over the short- and long-term. The design reclamation cover thicknesses for the tailings management cells range from 9.5 to 10.5 feet. The minimum design cover thickness of 9.5 feet was used for the lysimeter area of the Primary Test Section to evaluate the lower bound reclamation cover thickness for the tailings management cells. The remaining area within the test section was constructed to the full-depth Cell 2 cover profile (10.5 feet). The cover profile within the lysimeter is shown on Figure 3. The reclamation cover contains the following layers, listed in order from top to bottom: Layer 4 – 0.5 feet thick Erosion Protection Layer (topsoil-gravel admixture) Layer 3 – 3.5 feet thick Growth Medium Layer (loam to sandy clay) Layer 2 – 3.0 to 4.0 feet thick Compacted Cover (highly compacted loam to sandy clay) Layer 1 – 2.5 feet thick (minimum) Interim Fill Layer (loam to sandy clay) The Primary Test Section is in the southeast corner of Cell 2, as shown in Figure 2. The test section was constructed as a design-build project during reclamation cover construction using procedures adopted from the test section installation instructions developed by the United States Environmental Protection Agency (EPA) Alternative Cover Assessment Program (ACAP) (Benson et al., 1999, 2001). The test section is approximately 100 feet by 100 feet, with a 32-feet by 64-feet lysimeter centered within the test section. The longer side of the lysimeter is oriented parallel to the cover slope. The lysimeter collects percolation from the base of the cover, surface runoff, and interflow from the textural interface between the interim fill (Layer 1) and compacted cover (Layer 2). Sensors monitor hydrologic state variables (temperature and water content) within the cover. Percolation rate, lateral drainage, runoff, internal state conditions, and meteorological data are recorded continuously using a data logger near the southern edge of the test section. The Reclamation Plan (EFRI, 2018) provides detailed design information for the cover and Primary Test Section. 11 WHITE MESA URANIUM MILL CELL 2 RECLAMATION COVER 2019 ANNUAL PERFORMANCE MONITORING REPORT Primary Test Section Hydrologic Monitoring 3.1 3.0 PRIMARY TEST SECTION HYDROLOGIC MONITORING Data collected from the Primary Test Section from September 9, 2016 to December 29, 2019 are described in the annual Primary Test Section report in Appendix A. Data in this report represent the first three full calendar years (2017, 2018, and 2019) of monitoring. Table 1 summarizes the water balance. Table 1. Primary Test Section Water Balance for 2016 to 2019 Calendar Year Water Balance Quantities (mm) Precipitation Runoff Lateral Flow ET Change Storage Percolation 2016 60 0.0 0.0 35 17 0.0 2017* 223 0.0 0.0 325 39 0.6 2018 163 0.0 0.0 124 41 0.9 2019 308 0.3 0.0 325 3 1.0 *Damage from vault flooding precluded measuring flows 7 February 2017 – 25 March 2017 Seasonal water balance trends are consistent with expectations for a water balance cover in a semi-arid climate. Precipitation at the test section in 2019 (308 mm) was comparable, but lower than the long-term average recorded at the Blanding, Utah station (355 mm) operated by the NWS. Soil water storage increased substantially during the winter and early spring due to greater than average precipitation. The wet spring conditions supported an abundant stand of vegetation, which removed water from the cover profile in later spring and summer, depleting soil water storage throughout the spring. Nearly all the precipitation at the test section was returned to the atmosphere via evapotranspiration. Runoff and lateral flow were essentially nil, and percolation was 1.0 mm. Thermally driven flow appears responsible for nearly all the percolation. The annual percolation rate is similar to percolation rates reported in the literature for water balance covers in similar climates. The test section is functioning as expected and is consistent with the expectations for water balance covers in semi-arid climates. 7 7 I ,--- I I - I I - I I - I I - I I - I I - 11 WHITE MESA URANIUM MILL CELL 2 RECLAMATION COVER 2019 ANNUAL PERFORMANCE MONITORING REPORT Primary and Supplemental Test Sections Vegetation Inspection 4.1 4.0 PRIMARY AND SUPPLEMENTAL TEST SECTIONS VEGETATION INSPECTION Cedar Creek Associates, Inc. visited the Mill site on May 29, 2019 and on September 11, 2019 to inspect the status of plant development on the Primary and Supplemental Test Sections. Inspection results are summarized below, and Appendix B presents a full report with photos. Favorable precipitation conditions in October 2018 allowed for late season plant growth, and very favorable conditions in the winter and spring of 2019 facilitated a substantial increase in vegetation growth at the site, particularly on the Primary Test Section. Ground cover during the fall revegetation survey on Primary Test Section consisted of 65.9 percent live vegetation, 2.6 percent rock, 22.7 percent litter, and bare ground exposure of 8.8 percent. Perennial plant cover across the unit averaged 51.9 percent, with annual species comprising 14.0 percent. Ground cover during the fall revegetation survey on Supplemental Test Section consisted of 79.4 percent live vegetation, 0.2 percent rock, 8.0 percent litter, and bare ground exposure of 21.4 percent. Perennial plant cover across the unit averaged 2.0 percent, with annual species comprising 68.4 percent. The outlook for future years on the Primary Test Section is that plant cover of the seeded species should decrease once precipitation levels return to near average, leveling out between 30 to 40 percent, with about 40 percent cover as a maximum sustainable cover for this environment. The outlook for future years on the Supplemental Test Section is that plant cover of the seeded species should increase to about 15 to 25 percent in the third growing season in 2020 and to about 20 to 30 percent in the following years, with an eventual plant cover reaching about 40 percent as a maximum sustainable cover for this environment. This maximum cover for both test sections should stabilize in about seven years unless consecutive years of drought occur, and the trajectory for plant cover development is delayed. It is recommended that revegetation evaluation continue with spring and fall evaluations until plants are established in accordance with these expectations. The dynamic response to local precipitation conditions should be tracked until the revegetation community stabilizes. 11 WHITE MESA URANIUM MILL CELL 2 RECLAMATION COVER 2019 ANNUAL PERFORMANCE MONITORING REPORT Cell 2 Settlement and Water Level Monitoring 5.1 5.0 CELL 2 SETTLEMENT AND WATER LEVEL MONITORING Cell 2 includes settlement monuments and piezometers (Figure 4 shows locations). Settlement monuments were installed between 1989 and 2010. Existing settlement monuments were extended upward during Phase 1 cover construction. Standpipe piezometers were installed in June 2016 across Cell 2 during Phase 1 cover construction to monitor water levels within the tailings. After official performance monitoring is complete for the Primary and Secondary Test Sections, the settlement and dewatering data will be evaluated to determine if sufficient settlement has occurred to facilitate Phase 2 cover placement. The following sections discuss settlement monitoring and monitoring of water levels in the tailings during and after Phase 1 cover construction. 5.1 SETTLEMENT MONUMENTS Appendix C contains graphs showing settlement monument measurements from installation through December 2019. Table 2 lists the settlement measured since the start of Phase 1 cover construction (April 2016) through December 2019. Settlement totals during this period range from 0 to 0.5 feet. Settlement of the cover surface due to the Phase 1 cover loading is occurring as expected, with a relatively quick response to the additional loading, as occurred when the initial interim fill was placed on the tailings. The majority of total settlement due to Phase 1 cover placement is estimated to have occurred. Settlement is showing a decreasing trend and less than 0.1 feet of cumulative settlement was measured for 2019 for all the monuments (range of 0 to 0.06 feet). Prior to initiating Phase 2 cover placement, additional fill will be added to settled areas and the top surface of the compacted cover layer will be recompacted. Table 2. Cell 2 Top Surface Settlement Measured Between April 2016 and December 2019 Settlement Monument April 2016 to December 2019 Settlement (ft) 2019 Settlement (ft) Settlement Monument April 2016 to December 2019 Settlement (ft) 2019 Settlement (ft) 2W1 0.25 0.01 2W6-N 0.18 0.03 2W2 0.34 0.02 2W6-C 0.30 0.00 2W3 0.32 0.03 2W6-S 0.42 0.03 2W3-S 0.36 0.03 2W7-N -0.03 0.03 2W4-N 0.26 0.02 2W7-C 0.08 0.02 2W4-C 0.29 0.04 2W7-S 0.29 0.04 2W4-S 0.49 0.05 2E1-N 0.20 0.03 2W5-N 0.25 0.03 2E1 0.28 0.03 2W5-C 0.31 0.02 2E1-1S 0.31 0.03 2W5-S 0.41 0.05 2E1-2S 0.43 0.06 I 1 1r--I ~ J ~ J ~ j J ~ I I I 11 WHITE MESA URANIUM MILL CELL 2 RECLAMATION COVER 2019 ANNUAL PERFORMANCE MONITORING REPORT Cell 2 Settlement and Water Level Monitoring 5.2 5.2 PIEZOMETERS Standpipe piezometers were installed across Cell 2 prior to the first phase of final cover placement to monitor changes in water levels in the tailings due to dewatering from the sump prior to and after final cover placement. These piezometers were completed within the tailings to provide information on the rate and extent of dewatering of the tailings. The piezometers were primarily adjacent to the settlement monuments to minimize damage to the piezometers during cover construction, while providing sufficient locations to evaluate tailings water levels. Appendix D presents figures showing water levels in the piezometers since installation (June 2016) through January 3, 2020. Figure D.1 shows the water levels for all the piezometers. For comparison, Figures D.2, D.3, and D.4 show the water levels in the piezometers on the west side of Cell 2 (excluding locations near the sump), near the sump, and on the east side of Cell 2 (excluding locations near the sump), respectively. Figures D.2 through D.4 show water levels are lower near the sump, indicating migration of water towards the sump. The figures show that piezometer water levels increased during the Phase 1 cover placement (late 2016 to early 2017), and then generally decreased until the wet winter/spring of 2019. The increase in water levels was expected during Phase 1 cover placement and is due to the excess pore water pressure from consolidation associated with the loading from the additional cover. In 2019, water levels for piezometers increased or were generally level for the majority of the year. These conditions are likely due to the significantly wet 2019 winter/spring. For the piezometers with increasing water levels in 2019, recent readings show a return to a decreasing trend in water levels. Overall, water levels have decreased since Phase 1 cover placement, which is summarized in Table 3. 11 WHITE MESA URANIUM MILL CELL 2 RECLAMATION COVER 2019 ANNUAL PERFORMANCE MONITORING REPORT Cell 2 Settlement and Water Level Monitoring 5.3 Table 3 Piezometer Water Level Elevations During and After Phase 1 Cover Placement Piezometer Location on Cell Maximum Measured Water Level Elevation during Phase 1 Cover Placement (ft) Measured Water Level Elevation on 1/3/2020 (ft) Change in Water Level Elevation since Phase 1 Cover Placement (ft)* C2-P01 West 5612.55 5611.75 -0.80 C2-P02 West 5613.30 5612.32 -0.98 C2-P03 West 5612.31 5611.43 -0.88 C2-P04 West 5613.97 5612.88 -1.09 C2-P05 West 5608.39 5607.10 -1.29 C2-P06 West 5609.21 5608.05 -1.16 C2-P07 West 5610.08 5608.60 -1.48 C2-P08 West 5605.25 5604.08 -1.17 C2-P09 Near Sump 5602.94 5601.89 -1.05 C2-P10 Near Sump 5601.54 5600.14 -1.40 C2-P11 Near Sump 5602.38 5600.27 -2.11 C2-P12 Near Sump 5599.45 5596.13 -3.32 C2-P14 Near Sump 5603.99 5602.58 -1.41 C2-P15 Near Sump 5604.01 5602.48 -1.53 C2-P16 Near Sump 5604.37 5602.95 -1.42 C2-P13 East 5605.72 5604.75 -0.97 C2-P17 East 5607.49 5606.79 -0.70 C2-P18 East 5607.82 5606.21 -1.61 C2-P19 East 5609.09 5607.85 -1.24 C2-P20 East 5610.63 5609.63 -1.00 C2-P21 East 5612.40 5610.28 -2.12 C2-P22 East 5613.39 5610.84 -2.55 C2-P23 East 5614.24 5611.87 -2.37 *Negative number indicates a decrease in water level. 1~ I I I I I I I ~ ,--- I I -I I ~ I t-- - I I r-- --I I - I I ~ ~ I -I -I I ~ -I I - I I -I I - I I ~ -I I I I I I I I I I ~ -I I I I - I_ I I I I _J 11 WHITE MESA URANIUM MILL CELL 2 RECLAMATION COVER 2019 ANNUAL PERFORMANCE MONITORING REPORT Conclusions 6.1 6.0 CONCLUSIONS Hydrology of the Primary Test Section during 2019 was consistent with expectations for a water balance cover in a semi-arid environment. Nearly all precipitation at the test section returned to the atmosphere via evapotranspiration. Runoff and lateral flow were essentially nil, and percolation was 1.0 mm. The annual percolation rate is similar to percolation rates reported in the literature for water balance covers in similar climates. The test section is functioning as expected and is consistent with the expectations for water balance covers in semi-arid climates. Following the revegetation evaluations in 2018, the seeding of the Primary and Supplemental Test Sections was determined to be successful, although very low precipitation was observed for most of 2018. Favorable precipitation conditions in October 2018 allowed for late season plant growth, and very favorable conditions in the winter and spring of 2019 facilitated a substantial increase in vegetation growth at the site, particularly on the Primary Test Section. Plant cover is expected to continue to level out or increase and should stabilize in about seven years unless consecutive years of drought occur, and the trajectory for plant cover development is delayed. Total Cell 2 cover surface settlement ranged from 0 to 0.5 feet. This represents total settlement from the start of Phase 1 cover construction (April 2016) through December 2019. Settlement trends are similar to settlement monitoring after the initial interim fill was placed, with a quick response to the additional loading. The majority of total settlement due to Phase 1 cover placement is estimated to have occurred. Settlement is showing a decreasing trend and less than 0.1 feet of cumulative settlement was measured for 2019 for all the monuments. Water levels for piezometers increased during the Phase 1 cover placement and then generally decreased until the wet winter/spring of 2019. In 2019, water levels for piezometers increased or were generally level for the majority of the year and was likely due to the significantly wet 2019 winter/spring. For the piezometers with increasing water levels in 2019, recent readings show a return to a decreasing trend in water levels. Overall, water levels have decreased since Phase 1 cover placement. 11 WHITE MESA URANIUM MILL CELL 2 RECLAMATION COVER 2019 ANNUAL PERFORMANCE MONITORING REPORT References 7.1 7.0 REFERENCES Benson, C., T. Abichou, X. Wang, G. Gee, and W. Albright, 1999. Test Section Installation Instructions – Alternative Cover Assessment Program, Geotechnics Report 99-3, Geological Engineering, University of Wisconsin-Madison. Benson, C., Abichou, T., Albright, W., Gee, G., and Roesler, A. 2001. Field Evaluation of Alternative Earthen Final Covers, International J. Phytoremediation, 3(1), 1-21. Energy Fuels Resources (USA) Inc. (EFRI), 2016. Reclamation Plan, White Mesa Mill, Blanding Utah, Revision 5.1, December 5. Energy Fuels Resources (USA) Inc. (EFRI), 2018. Reclamation Plan, White Mesa Mill, Blanding Utah, Revision 5.1, February 8. Stantec Consulting Services Inc. (Stantec), 2017a. White Mesa Uranium Mill, Cell 2 Cover Performance Test Section As-Built Report, June 30. Stantec Consulting Services Inc. (Stantec), 2017b. White Mesa Uranium Mill, Cell 2 Phase 1 Cover As- Built Report, July 18. Stantec Consulting Services Inc. (Stantec), 2018a. White Mesa Uranium Mill, Cell 2 Supplemental Test Section As-Built Report, February 26. Stantec Consulting Services Inc. (Stantec), 2018b. White Mesa Uranium Mill, Cell 2 Reclamation Cover 2017 Annual Performance Monitoring Report, May 2. Stantec Consulting Services Inc. (Stantec), 2019. White Mesa Uranium Mill, Cell 2 Reclamation Cover 2018 Annual Performance Monitoring Report, April 5. 11 WHITE MESA URANIUM MILL CELL 2 RECLAMATION COVER 2019 ANNUAL PERFORMANCE MONITORING REPORT FIGURES REGIONAL LOCATION MAP FIGURE 1 1009740 LOC MAP WHITE MESA MILL TAILINGS RECLAMATION MAR 2019ENERGY FUELS REFERENCE: ADAPTED FROM FIGURE 1-1 IN DENISON MINES (USA) ~~:~g1~AGTIOUNT,AH2009. RECLAMATION PLAN WHITE MESA MILL , · VERSION 4.0. NOVEMBER. ' PROJECT !nKmLr-E _______ __JC) Stantec DATE FILE NAME SUPPLEMENTAL TEST SECTION LOCATION MILL SITE BOUNDARY CELL 1 CELL 2 CELL 3 CELL 4A CELL 4B DESIGNED APPROVED FIGURE CHECKED ENERGY FUELS WHITE MESA MILL TAILINGS RECLAMATION BLANDING, UTAH SITE LOCATION MAP 2 233001001 MARCH 2019 K REED B VAN M DAVIS PRIMARY TEST SECTION DRAWING BmBtNCt(s)· 1. Al. 00DIIJIWD REFDI: 1D UTAH STATE PLANE IOlfTH. ~ US SUIMY Fm . .2. NMERf SOI.RC£. ■~ 20141 () Stantec 9.5' 0.5' 3.5' 3.0' 2.5' EROSION PROTECTION LAYER LAYER 3 - GROWTH MEDIUM LAYER 1 - INTERIM FILL LAYER 2 - COMPACTED COVER TAILINGS VEGETATION COVER PROFILE WITHIN LYSIMETER FIGURE 3 1009740 WM ET COVR MAR 2019 WHITE MESA MILL TAILINGS RECLAMATION ENERGY FUELS PROJECT ITI'i[E""TITL£ _____ _J () Stantec DATE FILE NAME RESTRICTED AREA BOUNDARY CELL2-P01 CELL2-P10 CELL2-P11 CELL2-P16 LEGEND: CELL 2 CELL 3 MILL SITE CELL 1 COVER PERFORMANCE TEST SECTION EXISTING GROUND SURFACE CONTOURS (IN FEET) (SEE DRAWING REFERENCE 2) LIMIT OF TOPOGRAPHIC SURVEY DESIGNED APPROVED FIGURE CHECKED ENERGY FUELS WHITE MESA MILL TAILINGS RECLAMATION BLANDING, UTAH CELL 2 SETTLEMENT MONUMENT AND PIEZOMETER LOCATIONS 4 233001001 MARCH 2019 K REED B VAN M DAVIS 06 2\J/tELL2- CELL2-P04 06 2W3-S .-~·.········· · /,. · C)" 1/;. ·· .... •' -. . . . v -P09 06 2W~ 5622 CELL2-P14 0 ~ 2W6-C CELL2-P07 06 2W4-S 0 0: CELL2-P15 1. EXISTING TOPOGRAPHY BASED UPON FILE PROVIDED FROl.l ENERGY FUELS ON JULY 20, 2015. PER ENERGY FUELS, GROUND SURFACE CONTOURS ARE FROt.l 2012 AERIAL SURVEY CONDUCTED BY JONES &: DaMILLE ENGINEERING INC., EXCEPT FOR CELLS 2 AND 3. CELL 2 TOPOGRAPHY FROM ENERGY FUELS SURVEY CONDUCTED OCTOBER 2013. CELL 3 TOPOGRAPHY FROM ENERGY FUELS SURVEY CONDUCTED ON JULY 8, 201 +. 2. EXISTING TOPOGRAPHY BASED ON FILES PROVIDED FROM ENERGY FUELS IN MAY 2017. CONTOURS ARE FROM DRONE SURVEY CONDUCTED BY JONES & DEMILLE ENGINEERING ON JUNE 9, 2017. • G~ C!':LL2-P18 06 2W7-C "' () Stantec 7 EXISTING GROUND SURFACE ELEVATION, FEET (SEE REFERENCE 1) EXISTING ROAD EXISTING WATER EXISTING TRAIL --x--EXISTING FENCE □ EXISTING STRUCTURE 6 EXISTING SETTLEMENT MONITORING POINT 0 CELL 2 PIEZOMETER LOCATIONS ,,,~ APPROXIMATE SUMP AND DRAIN I \ '-/ ACCESS LOCATION j I ,-_ WHITE MESA URANIUM MILL CELL 2 RECLAMATION COVER 2019 ANNUAL PERFORMANCE MONITORING REPORT APPENDICES D WHITE MESA URANIUM MILL CELL 2 RECLAMATION COVER 2019 ANNUAL PERFORMANCE MONITORING REPORT Appendix A FIELD HYDROLOGY OF THE CELL 2 PRIMARY TEST SECTION AT THE WHITE MESA MILL D FIELD HYDROLOGY OF THE CELL 2 PRIMARY TEST SECTION AT THE WHITE MESA MILL ANNUAL REPORT FOR CALENDAR YEAR 2019 WHITE MESA MILL – TAILINGS MANAGEMENT CELL 2 ENERGY FUELS RESOURCES (USA) INC. SAN JUAN COUNTY, UTAH Craig H. Benson, PhD, PE, NAE 2 February 2019 i EXECUTIVE SUMMARY This report describes monitoring data collected from the Primary Test Section at the White Mesa Mill in San Juan County, Utah, which is being used to evaluate the water balance cover for Cell 2 of the tailings management area at the mill. The data were collected during the period 9 September 2016 to 29 December 2019 (last automated data download of 2019). The data set includes the first three full calendar years (2017 - 2019) of monitoring for the test section. This report emphasizes data collected in 2019. The water balance of the test section is summarized as follows: Water Balance Quantity (mm) 2016* 2017 2018 2019 Precipitation 60 223 163 308 Runoff 0 0 0 0.3 Lateral Flow 0 0 0 0 Change in Storage 17 39 41 3 Evapotranspiration 35 325 122 325 Percolation 0.0 0.6 0.9 1.0 *partial year, monitoring began on 9 September 2016. The hydrology of the test section during 2019 was consistent with expectations for a water balance cover in a semi-arid environment. Precipitation in 2019 (308 mm) was comparable, but lower than the long-term average for the nearby Blanding, Utah station (355 mm, located at 37° 62' N, 109° 47' W with elevation 1829.1 m) operated by the National Weather Service. Winter and spring 2019 were much wetter than average, and summer much drier than average. Soil water storage increased substantially in the winter and spring in response to the precipitation. An abundant stand of vegetation emerged in response to the wet spring, resulting in rapid depletion of soil moisture in late spring via evapotranspiration. Late fall was also wetter than average, resulting in an increase in soil water storage. Annual runoff and annual lateral flow were essentially nil. Annual percolation was 1.0 mm, which compares well with percolation rates reported in the literature for water balance covers in similar climates. Thermally driven flow appears responsible for nearly all percolation recorded to date. ii TABLE OF CONTENTS EXECUTIVE SUMMARY i LIST OF TABLES AND FIGURES iii 1. INTRODUCTION 1 2. METEOROLOGICAL DATA 2 3.TEST SECTION DATA 6 4. SUMMARY AND CONCLUSIONS 16 5. REFERENCES 17 ATTACHMENT A – DATA QUALITY REPORTS FOR 2019 18 iii LIST OF TABLES AND FIGURES Table 1. Water balance quantities for the final cover test section at White Mesa from 09/29/16 to 12/29/19. Fig. 1. Schematic of cover profile evaluated at White Mesa. Fig. 2. Cross-section of test section showing layering (orange = interim layer, yellow = compacted layer, green = growth medium layer), lysimeter, pipe runs, and vault used to monitor flows. Fig. 3. Comparison of on-site meteorological data to historical data from the Blanding station operated by NWS: (upper) air temperature and (lower) cumulative precipitation. Fig. 4. Cumulative precipitation and potential evapotranspiration (PET) on-site during 2019. PET was computed using the FAO method described in Allen et al. (1998) with on-site meteorological data. Fig. 5. Water balance graph for test section through end of 2019. Fig. 6. Relationship between annual precipitation (Pa), annual potential evapotranspiration (PETa), and annual evapotranspiration (ETa) for test section at White Mesa (solid squares) and from ACAP and other international studies (solid blue circles) as reported by Apiwantragoon et al. (2014). Fig. 7. Vegetation on surface of test section on 31 May 2018 (a) and 31 May 2019 (b). Photographs from Cedar Creek (2020). Fig. 8. Daily average air temperature and daily average soil temperature at various depths in the test section (green = growth medium, orange = compacted layer, yellow = interim layer). Fig. 9. Soil water storage and cumulative percolation over time for the test section. Vertical dashed lines correspond to annual onset and cessation of percolation. Fig. 10. Annual percolation for the test section at White Mesa in context of data from other sites in ACAP and other international studies as reported by Apiwantragoon et al. (2014). 1 1. INTRODUCTION The Primary Test Section was constructed at the White Mesa Mill in San Juan County, Utah in Summer 2016 to evaluate the field-scale hydrology of the final cover placed over the Cell 2 tailings management cell. The profile of the final cover design is shown in Fig. 1 and a cross- section of the test section is shown in Fig. 2. The cover is an earthen design employing water balance principles that is comprised of four layers (bottom to top): well-graded interim layer (760 mm, 2.5 ft), fine-textured compacted layer (915 mm, 3.0 ft), growth medium layer (1070 mm, 3.5 ft), and gravel-amended topsoil layer (150 mm, 0.5 ft) (Fig. 1). Construction documentation for the test section is described in Stantec (2017). The test section includes a drainage lysimeter and associated instruments (Fig. 2) based on the lysimeter design developed for the Alternative Cover Assessment Program (ACAP) as described in Benson et al. (1999, 2001). The instruments are used to monitor fluxes from the cover profile (runoff, lateral flow, percolation), state variables (soil water content and temperature at discrete monitoring points), and meteorological conditions. A datalogger collects data from the sensors at intervals ranging from hourly to as short as 30 seconds depending on the hydrological condition. A cellular modem transmits data stored on the datalogger to a computer off site on a daily basis. Data collection began on 29 September 2016 and continues uninterrupted. The sensors and data acquisition system used to monitor the test section are maintained and recalibrated annually. A data quality evaluation is conducted monthly for measurements from all sensors, and a data quality report (DQR) is issued quarterly. Attachment A contains DQRs for 2019. Instrumentation calibration and maintenance is conducted annually, most recently on 11 September 2019. This report describes data collected since inception of the test section, with particular emphasis on data collected in 2019. Section 2 compares meteorological data collected on-site to historical data from a nearby monitoring station operated by the National Weather Service (NWS). 2 Section 3 describes hydrological data from the test section. Section 4 provides a summary and conclusions. 2. METEOROLOGICAL DATA Detailed comparisons are made quarterly between the on-site meteorological data and meteorological data compiled by the National Weather Service at the Blanding, Utah station ( 37° 62' N, 109° 47' W, elevation 1829.1 m). Comparisons to NWS data in the quarterly DQRs (see Attachment A) indicate agreement between the measurements on site and those made by NWS. Fig. 3 compares the average daily precipitation and the average daily air temperature measured on-site with long-term historical averages reported by the NWS at the Blanding station. Average air temperature at the test section generally falls within the long-term high and low temperatures recorded at the Blanding station (Fig. 3a), except for three brief cold periods in February, May, and October. The on-site precipitation in 2019 was comparable, but lower than the long-term average annual precipitation at the Blanding station (308 vs. 355 mm). The winter and spring were much wetter than average, and summer was much drier than average. Late fall was also wetter than average. The long-term average precipitation record does not exhibit the variability inherent in the actual precipitation record. Smoothing associated with long-term temporal averaging makes the long-term precipitation record smoother and more gradually varying compared to actual records. When a daily precipitation record is averaged over long periods, the number of days with non- zero precipitation diminishes (in the limit, the number of non-zero precipitation days tends to zero). The number of days with large precipitation events diminishes as well. For this reason, long-term precipitation records are not recommended for use in simulating the hydrology of covers (Albright et al. 2010), but they are useful for comparative analysis. 3 Fig. 1. Schematic of cover profile evaluated at White Mesa. 4 Fig. 2. Cross-section of test section showing layering (orange = interim layer, yellow = compacted layer, green = growth medium layer), lysimeter, pipe runs, and vault used to monitor flows. . 5 Fig. 3. Comparison of on-site meteorological data to historical data from the Blanding station operated by NWS: (upper) air temperature and (lower) cumulative precipitation. 6 Fig. 4 shows cumulative precipitation and potential evapotranspiration (PET) computed with the FAO method (Allen et al. 1998) for 2019 data. PET far exceeds precipitation throughout much of the year, indicating an excess of energy for evaporation and transpiration relative to the amount of water to manage. 3.TEST SECTION DATA Table 1 summarizes the annual water balance for the test section. Fig. 5 shows the water balance graph for the test section. Table 1. Water balance quantities for the final cover test section at White Mesa from 09/29/16 to 12/29/19 (last day of automated downloads for 2019). Calendar Year Water Balance Quantities (mm) Precipitation Runoff Lateral Flow ET D Storage Percolation 2016 60 0.0 0.0 35 17 0.0 2017* 223 0.0 0.0 325 39 0.6 2018 163 0.0 0.0 124 41 0.9 2019 308 0.3 0.0 325 3 1.0 *damage from vault flooding precluded measuring flows 7 February 2017 – 25 March 2017. Fig. 5 shows cumulative quantities for each of the water balance fluxes (precipitation, evapotranspiration, runoff, lateral flow, and percolation) as a function of time. Percolation is the flux from the base of the cover that is captured by the geocomposite drain in the base of the lysimeter and would normally flow into the tailings. Lateral flow is the flux of liquid occurring laterally at the interface between the growth medium and the compacted layer and is captured by a collection point at the downslope edge of the lysimeter. Fig. 5 also shows soil water storage (total water stored in the cover per unit surface area) as function of time. Soil water storage is computed by integrating the water content measurements over the volume of the test section at a given point in time. 7 Fig. 4. Cumulative precipitation and potential evapotranspiration (PET) on-site during 2019. PET computed using the FAO method described in Allen et al. (1998) with on-site meteorological data. 8 Fig. 5. Water balance graph for test section through end of 2019. 9 Each water balance quantity is measured directly except for evapotranspiration (ET), which is computed as the residual of the daily water balance: ET = P – R – L – Pr – DS (1) where P = daily precipitation, R = daily runoff, L = daily lateral flow, Pr = daily percolation, and DS = daily change in soil water storage. ET computed with Eq. 1 includes actual ET and any errors in the water balance. ET computed with Eq. 1 was 325 mm in 2019, which reflects the wet winter and spring periods, as well as wet conditions in late Fall 2018. Cumulative annual ET computed with Eq. 1 is in agreement with the generalized relationship between annual ET, potential evapotranspiration (PET), and precipitation for water balance covers and natural watersheds, as shown in Fig. 6. Annual PET in Fig. 6 was computed using the on-site meteorological data with the FAO method described in Allen et al. (1998) and shown in Fig. 4. The seasonal water balance trends shown in Fig. 5 are consistent with expectations for a water balance cover in a semi-arid climate. Soil water storage increased substantially during the winter and early spring due to greater than average precipitation. The wet spring conditions supported an abundant stand of vegetation (Fig. 7), which removed water from the cover profile in later spring and summer, depleting soil water storage throughout the spring. Subfreezing conditions did not occur in the cover during 2019 due to mild winter weather conditions (Fig. 8). Thus, water was able to move across the surface of the cover unimpeded nearly the entire year. Percolation began on 25 July 2019, about one month later than in 2018, and similar to the initiation time in 2017 (Fig. 9). Percolation ceased on 27 October 2019, several months earlier than the previous year. For each year in the record, percolation is unrelated to the soil water storage record, and occurs when soil water storage is near a minimum. Percolation also occurs during when the thermal gradient is oriented downward (thermal flow from warmer to cooler areas), with the initiation and cessation of percolation apparently aligned with inversion of the thermal gradient 10 Fig. 6. Relationship between annual precipitation (Pa), annual potential evapotranspiration (PETa), and annual evapotranspiration (ETa) for test section at White Mesa (solid squares) and from ACAP and other international studies (solid blue circles) reported by Apiwantragoon et al. (2014). 11 Fig. 7. Vegetation on surface of test section on 31 May 2018 (a) and 31 May 2019 (b). Photographs from Cedar Creek (2020). (a) 31 May 2018 (b) 31 May 2019 12 Fig. 8. Daily average air temperature and daily average soil temperature at various depths in the test section (green = growth medium, orange = compacted layer, yellow = interim layer). 13 Fig. 9. Soil water storage and cumulative percolation over time for the test section. Vertical dashed lines correspond to annual onset and cessation of percolation. 14 in early summer and later in the fall (Fig. 8). Thermally driven flows can be a substantial portion of deep drainage in semi-arid and arid environments (Milly 1996). Fig. 10 shows annual percolation from the test section for 2017, 2018, and 2019 along with data compiled from USEPA’s Alternative Cover Assessment Program (ACAP) and other data sources, as reported by Apiwantragoon et al. (2014). Percolation data for 2017 and 2018 fall in the middle of the data reported by Apiwantragoon et al. (2014) for the bin corresponding to annual precipitation between 0 to 250 mm/yr. For 2019, the percolation falls at the lower end of the data reported by Apiwantragoon et al. (2014) for annual precipitation between 250 and 500 mm/yr. This agreement indicates consistency with other water balance covers in similar climates. 15 Fig. 10. Annual percolation for the test section at White Mesa in context of data from other sites in ACAP and other international studies as reported by Apiwantragoon et al. (2014). 16 4.SUMMARY AND CONCLUSIONS This report describes hydrological and meteorological data collected from the Cell 2 test section at the White Mesa Mill near Blanding, Utah. Data are reported for the period 29 September 2016 to 29 December 2019 (date of last automated data download in 2019), with the discussion emphasizing data collected in 2019. The monitoring system for the test section was collecting all of the required data, except for a short period in 2017 when the flow monitoring systems were not functioning due to flooding of the vault by snow melt (7 February 2017 through 25 March 2017). Data collection continued uninterrupted since vault repairs were made in May 2017. The following observations and conclusions are made based on the data collected: •Precipitation at the test section in 2019 (308 mm) was comparable, but lower than the long- term average recorded at the Blanding, Utah station (355 mm) operated by the NWS. The winter and spring were wetter than historical averages, and the summer drier than the historical average. The late fall was also wetter than the historical average. The wet winter and spring supported an abundant stand of vegetation. Evapotranspiration by the vegetation was effective in removing water stored in the cover profile during the wet winter and spring. •The test section hydrology is consistent with expectations for water balance covers in semi- arid locations in the western US. Nearly all precipitation at the test section was returned to the atmosphere via evapotranspiration. Runoff and lateral flow were essentially nil, and percolation was 1.0 mm. The annual percolation rate is similar to percolation rates reported in the literature for water balance covers in similar climates. •Thermally driven flow appears responsible for nearly all the percolation. Each year percolation begins when soil water storage is near its lowest, and the thermal gradient is downward. Thermally driven flows are common in semi-arid and arid climates. •The test section is functioning as expected and is consistent with the expectations for water balance covers in semi-arid climates. 17 5.REFERENCES Albright, W., Benson, C., and Waugh, W. (2010), Water Balance Covers for Waste Containment: Principles and Practice, ASCE Press, Reston, VA, 158 p. Allen, R., Pereira, L., Raes, D., and Smith, M. (1998). Crop Evapotranspiration-Guidelines for Computing Crop Water Requirements.” FAO Irrigation and Drainage Paper 56, Food and Agricultural Organization of the United Nations, Rome. Apiwantragoon, P., Benson, C., and Albright, W. (2014), Field Hydrology of Water Balance Covers for Waste Containment, J. Geotech. and Geoenvironmental Eng., 04014101-1-20. Benson, C., Abichou, T., Albright, W., Gee, G., and Roesler, A. (2001), Field Evaluation of Alternative Earthen Final Covers, International J. Phytoremediation, 3(1), 1-21. Benson, C., Abichou, T., Wang, X., Gee, G., and Albright, W. (1999), Test Section Installation Instructions – Alternative Cover Assessment Program, Environmental Geotechnics Report 99-3, Dept. of Civil & Environmental Engineering, University of Wisconsin-Madison. Cedar Creek (2020), White Mesa Mill Site, 2019 Revegetation Evaluation Cell 2 Primary and Supplemental Test Sections, report prepared for Energy Fuels Resources Inc by Cedar Creek Associates, Inc., Fort Collins, CO. Milly, P. (1996), Effects of Thermal Vapor Diffusion on Seasonal Dynamics of Water in the Unsaturated Zone, Water Resources Research, 32(3), 509-518. Stantec Consulting Services Inc. (Stantec), 2017, White Mesa Uranium Mill, Cell 2 Cover Performance Test Section As-Built Report, June 30. 18 ATTACHMENT A DATA QUALITY REPORTS FOR 2019 V ENERGY FUELS Energy Fuels Resources (USA) Inc. 225 Union Blvd. Suite 600 Lakewood, CO, US, 80228 303 974 2140 www.energyfuels.com CC: David C. Frydenlund Terry Slade Logan Shumway Scott Bakken Paul Goranson May 17, 2019 Sent VIA E-MAIL AND EXPRESS DELIVERY Mr. Ty L. Howard Director Division of Waste Management and Radiation Control Utah Department of Environmental Quality 195 North 1950 West P.O. Box 144880 Salt Lake City, UT 84114-4880 Re: Transmittal of Ql-19 Data Quality Report ("DQR") for the White Mesa Cell 2 Cover Test Section Monitoring Dear Mr. Howard: In accordance with the Stipulation and Consent Agreement ("SCA" dated February 23, 2017) between the Division of Waste Management and Radiation Control ("DWMRC") and Energy Fuels Resource (USA) Inc. ("EFRl"), EFRI constructed a cover performance monitoring test section on Cell 2 in 2016 and initiated performance monitoring. This letter transmits the data quality report for monitoring data collected during the first quarter of 2019. This report is being provided to DWMRC for information only, as submittal of this report is not a requirement of the SCA since the official test section monitoring time period has not yet started. Please note that this report is for quality assurance only and does not provide interpretive information. Interpretive information is provided in annual reports. For your convenience, two hard copies of the report and two CDs, each containing a word searchable electronic copy of the files, will be mailed to DWMRC. If you should have any questions regarding this transmittal please contact me at 303-389-4134. Yours very truly, +(�Jtr� ENERGY FUELS RESOURCES (USA) INC. Kathy Weinel Quality Assurance Manager Q1-19 DATA QUALITY REPORT FOR THE PRIMARY TEST SECTION WHITE MESA MILL – TAILINGS MANAGEMENT CELL 2 ENERGY FUELS RESOURCES (USA) INC. SAN JUAN COUNTY, UTAH 11 May 2019 1 1.0 INTRODUCTION This data quality report (DQR) was prepared to record data quality assurance for the White Mesa Mill cover performance monitoring test section (Primary Test Section) for first quarter 2019 (Q1-19). This report is documentary and not interpretative. The annual report includes interpretation of the monitoring data. The Primary Test Section was constructed in August – September 2016 over tailings management Cell 2 at Energy Fuels Resources (USA) Inc.’s White Mesa Mill in San Juan County, Utah. Hydrological monitoring was initiated on 29 September 2016. A large-scale “ACAP-style” drainage lysimeter is used to monitor the test section. The lysimeter is equipped to monitor all water balance components along with meteorological data. Fig. 1 shows a profile of the final cover being evaluated at White Mesa (minimum thickness). Fig. 2 shows a cross-sectional schematic of the lysimeter. The test section is instrumented with two nests of vertically stacked and co-located sensors to monitor soil temperature and soil water content, as illustrated in Figs. 1 and 2. The nests are on the centerline of the test section at the upper and lower 1/3 points. Probes in the lower nest are odd-numbered and probes in the upper nest are even numbered. The water content probes were calibrated with on-site soils collected during construction. Temperature compensation was incorporated into the calibrations. Flows from the runoff, lateral flow (interflow), and percolation collection points in the test section are routed via pipe (Fig. 2) to collection basins in a subsurface vault downslope from the test section. Flow into each basin is monitored by tipping buckets and a pressure transducer. Flows reported by the tipping bucket are described in terms of “tips,” whereas water elevations reported by the transducers are reported as “stage.” Flows are reported in mm of water per unit area. The tipping buckets and pressure transducers were calibrated initially in September 2016, and re-calibrated on 10 May 2017, 14 November 2017, and 27 June 2018. 2.0 WATER BALANCE DATA Data in this DQR were collected during Q1-19 from 25 December 2018 to 24 March 2019. These dates align with automated data downloads and do not correspond precisely to the start and end of Q1-19. Data for 25 March 2019 and onward will be included in the Q2-19 report. Fig. 3 shows the water balance graph for the test sections and Table 1 summarizes the water balance quantities. Fig. 4 shows cumulative percolation and daily precipitation for both test sections. Figs. 5-34 show data from each sensor collected during Q1-19. The quality assurance summary is on pp. 7-8. The site received substantial precipitation in Q1-19, primarily as snow. Melting of the snow and rain on snow resulted in a modest amount of precipitation and infiltration. Increases in water content were observed in the growth medium, but not in the compacted layer or the interim layer. No lateral flow occurred (Fig. 4), which is consistent with infiltration not penetrating the compacted layer. A small amount of percolation was recorded in Q1-19 corresponding to tailing of the percolation at the end of 2018. Percolation ceased on 7 January 2019. 2 No water ingress into the vault was recorded during the snowmelt in Q1-19, indicating that the grading and other repairs made in 2017 were effective in preventing infiltration of snowmelt water into the vault. 3.0 CONCERNS • Significant differences in water content exist between Probes 1 and 2 and between Probes 3 and 4. These differences have existed since 2017 and are a response to lateral water movement above the compacted layer associated with infiltration of snowmelt in 2017. These differences are not a substantive concern and are diminishing slowly. Water contents reported by these probes will continue to be compared during future quality control activities. • A brief outage of line power to the datalogger and vault pump was recorded late in January 2019. This outage was confirmed with personnel at the plant. No data loss occurred, as the datalogger is powered by batteries that are recharged by solar panels and line power. 4.0 ACTION ITEMS • Comparison of water content Probes 1 and 2 and Probes 3 and 4 should continue. 3 Fig. 1. Schematic of cover profile evaluated at White Mesa. 4 Fig. 2. Schematic of lysimeter used for the White Mesa Primary Test Section. 5 Table 1. Water balance quantities for the final cover test section at White Mesa from 09/29/16 to 03/24/19. Calendar Year Water Balance Quantities (mm) Precipitation Runoff Lateral Flow ET ∆ Storage Percolation 2016 59.9 0.03 0.00 34.6 16.9 0.00 2017* 222.7 0.06 0.00 324.8 39.4 0.65 2018 163.4 0.09 0.00 124.6 37.9 0.90 2019 174.5 0.19 0.00 68.5 147.9 0.03 *Damage from vault flooding precluded measuring flows from 7 February 2017 – 25 March 2017. 6 0 200 400 600 800 0 200 400 600 800 9/20/16 2/20/17 7/24/17 12/25/17 5/27/18 10/28/18 3/31/19 White Mesa, UT Soil Water Storage On-Site Precipitation On-Site Evapotranspiration Surface RunoffPercolation NWS Evapotranspiration NWS Precipitation Lateral Flow Vault Flooded So i l W a t e r S t o r a g e , C u m u l a t i v e R u n o f f , L a t e r a l F l o w , an d P e r c o l a t i o n ( m m ) Cu m u l a t i v e P r e c i p i t a t i o n a n d E v a p o t r a n s p i r a t i o n ( m m ) Fig. 3. Water balance quantities for the final cover test section at White Mesa from 09/29/16 to 03/24/19. 7 DATA QUALITY REPORT SUMMARY: Q1-19 White Mesa Primary Test Section 12/25/18 through 03/24/19 Water Balance Summary •Table 1 summarizes the water balance of the test section since inception. •Fig. 3 is the water balance graph for the test section since inception. •Fig. 4 shows a graph of daily precipitation and cumulative percolation for the test section since inception. Meteorology •The battery and solar panel are working properly (Fig. 5). •All meteorological sensors are working properly (Figs. 6 -12). •The on-site precipitation data are consistent with the NWS data recorded at the Blanding station (Fig. 7) (KBDG, 37.62° N, 109.47° W, Elev.: 6001 ft). •The solar radiation data are consistent with data recorded at the NWS Blanding station (Fig. 12). Test Section •The WCR probes to measure water content are functioning properly (Figs. 13-19). Differences in water content of approximately 0.2 are reported by Probes 3 and 4 in the compacted layer at 2134 mm bgs. Differences in water content of approximately 0.1 are reported by Probes 1 and 2 in the interim layer at 2743 mm bgs (Figs 18 - 19). These differences in water content are real and reflect spatial variations in water content remaining from the deep penetration of a wetting front in Q1-17. •The thermocouples used to measure soil temperature are functioning properly (Fig. 20). •Flows reported by the transducer and tippers for runoff, lateral flow, and percolation are reasonably consistent (Figs. 21-29). •The vault stage has been negative, ranging from -2.0 to -3.0 mm, indicating no accumulation of water in the vault (Fig. 30). •The voltage sensor that monitors the power supply in the vault is functioning properly (Fig. 31). An intermittent loss of line power occurred in late January 2019. White Mesa personnel confirmed that there was a problem with the electrical service on that date. 8 No loss of power to the datalogger occurred during that period, as the data acquisition system relies on battery power. Electrical service from the plant is only used as a backup for the datalogger, and to power the pump within the vault if water accumulates. 9 0 10 20 30 40 50 0.0 0.5 1.0 1.5 2.0 9/20/16 2/20/17 7/24/17 12/25/17 5/27/18 10/28/18 3/31/19 Da i l y P r e c i p i t a t i o n ( m m ) Cu m u l a t i v e P e r c o l a t i o n ( m m ) White Mesa, UT Percolation Precipitation Fig. 4. Daily precipitation (blue) and cumulative percolation (red) for the final cover test section at White Mesa from 09/29/16 to 03/24/19. 10 11 12 13 14 12/20/18 1/5/19 1/21/19 2/7/19 2/23/19 3/11/19 3/28/19 Ba t t e r y ( V o l t s ) Fig. 5. Battery voltage for the datalogger at the final cover test section at White Mesa from 12/25/18 to 03/24/19. 10 12/20/18 1/5/19 1/22/19 2/8/19 2/25/19 3/14/19 3/31/19-0. 5 10 15 20 25 30 Da i l y P r e c i p i t a t i o n ( m m ) 0 Fig. 6. Daily precipitation at the final cover test section at White Mesa from 12/25/18 to 03/24/19. 12/20/18 1/6/19 1/23/19 2/9/19 2/25/19 3/14/19 3/31/190 50 100 150 200 Cu m u l a t i v e P r e c i p i t a t i o n ( m m ) 0 White Mesa Blanding Fig. 7. Cumulative precipitation measured at the final cover test section at White Mesa (blue) and NWS Blanding station (red) from 12/25/18 to 03/24/19. 11 0 10 20 30 40 0 10 20 30 40 White Mesa, UT Ti p p e r P r e c i p i t a t i o n ( m m ) Geonor Precipitation (mm) Fig. 8. Precipitation measured from tipper and Geonor precipitation gauge at the final cover test section at White Mesa from 09/29/16 to 03/24/19. 12/20/18 1/5/19 1/22/19 2/8/19 2/25/19 3/14/19 3/31/19 Min Air Temp Avg. Air Temp Max Air Temp -20 -10 0 10 20 30 Da i l y A i r T e m p e r a t u r e ( oC) Fig. 9. Daily air temperature at the final cover test section at White Mesa from 12/25/18 to 03/24/19. 12 12/20/18 1/5/19 1/22/19 2/8/19 2/25/19 3/14/19 3/31/19 Min RH Avg. RHMax RH 0 20 40 60 80 100 120 Da i l y R e l a t i v e H u m i d i t y ( % ) Fig. 10. Daily relative humidity at the final cover test section at White Mesa from 12/25/18 to 03/24/19. 0 2 4 6 8 10 12/20/18 1/5/19 1/22/19 2/8/19 2/25/19 3/14/19 3/31/19 Da i l y M e a n W i n d S p e e d ( m / s ) Fig. 11. Daily mean wind speed at the final cover test section at White Mesa from 12/25/18 to 03/24/19. 13 0 2000 4000 6000 8000 10000 12/20/18 1/5/19 1/22/19 2/8/19 2/25/19 3/14/19 3/31/19 So l a r R a d i a t i o n ( W - h r / m 2 ) White Mesa Blanding Fig. 12 Total daily solar radiation at the final cover test section at White Mesa (blue) and NWS Blanding station (red) from 12/25/18 to 03/24/19. 0.0 0.1 0.2 0.3 0.4 0.5 12/20/18 1/9/19 1/29/19 2/18/19 3/10/19 3/31/19 White Mesa, UT (457-mm Depth Growth Medium Layer) Vo l u m e t r i c W a t e r C o n t e n t Probe 13 Probe 14 Fig. 13. Volumetric water content in the growth medium layer (457 mm bgs) of the final cover test section at White Mesa from 12/25/18 to 03/24/19. Odd numbered probe is downslope and even is upslope. 14 0.0 0.1 0.2 0.3 0.4 0.5 12/20/18 1/5/19 1/22/19 2/8/19 2/25/19 3/14/19 3/31/19 White Mesa, UT(685-mm Depth Growth Medium Layer) Vo l u m e t r i c W a t e r C o n t e n t Probe 11 Probe 12 Fig. 14. Volumetric water content in the growth medium layer (685 mm bgs) of the final cover test section at White Mesa from 12/25/18 to 03/24/19. Odd numbered probe is downslope and even is upslope. 0.0 0.1 0.2 0.3 0.4 0.5 12/20/18 1/5/19 1/22/19 2/8/19 2/25/19 3/14/19 3/31/19 White Mesa, UT(914-mm Depth Growth Medium Layer) Vo l u m e t r i c W a t e r C o n t e n t Probe 9Probe 10 Fig.15. Volumetric water content in the growth medium layer (914 mm bgs) of the final cover test section at White Mesa from 12/25/18 to 03/24/19. Odd numbered probe is downslope and even is upslope. 15 0.0 0.1 0.2 0.3 0.4 0.5 12/20/18 1/5/19 1/22/19 2/8/19 2/25/19 3/14/19 3/31/19 White Mesa, UT(1524-mm Depth Compacted Layer) Vo l u m e t r i c W a t e r C o n t e n t Probe 8 Probe 7 Fig. 16. Volumetric water content in the compacted layer (1524 mm bgs) of the final cover test section at White Mesa from 12/25/18 to 03/24/19. Odd numbered probe is downslope and even is upslope. 0.0 0.1 0.2 0.3 0.4 0.5 12/20/18 1/5/19 1/22/19 2/8/19 2/25/19 3/14/19 3/31/19 White Mesa, UT(1829-mm Depth Compacted Layer) Vo l u m e t r i c W a t e r C o n t e n t Probe 6 Probe 5 Fig. 17. Volumetric water content in the compacted layer (1829 mm bgs) of the final cover test section at White Mesa from 12/25/18 to 03/24/19. Odd numbered probe is downslope and even is upslope. 16 0.0 0.1 0.2 0.3 0.4 0.5 12/20/18 1/5/19 1/22/19 2/8/19 2/25/19 3/14/19 3/31/19 White Mesa, UT(2134-mm Depth Compacted Layer) Vo l u m e t r i c W a t e r C o n t e n t Probe 4 Probe 3 Fig. 18. Volumetric water content in the compacted layer (2134 mm bgs) of the final cover test section at White Mesa from 12/25/18 to 03/24/19. Odd numbered probe is downslope and even is upslope. 0.0 0.1 0.2 0.3 0.4 0.5 12/20/18 1/5/19 1/22/19 2/8/19 2/25/19 3/14/19 3/31/19 White Mesa, UT(2743-mm Depth Interim Layer) Vo l u m e t r i c W a t e r C o n t e n t Probe 2 Probe 1 Fig. 19. Volumetric water content in the interim layer (2743 mm bgs) of the final cover test section at White Mesa from 12/25/18 to 03/24/19. Odd numbered probe is downslope and even is upslope. 17 . -10 0 10 20 30 12/20/18 1/5/19 1/22/19 2/8/19 2/25/19 3/14/19 3/31/19 White Mesa, UT 2743 mm D 2743 mm U 2134 mm D 2134 mm U 1829 mm D 1829 mm U 1524 mm D 1524 mm U 914 mm D 914 mm U 685 mm D 685 mm U 457 mm D 457 mm U So i l T e m p e r a t u e ( oC) 2743 mm (D) 457 mm (D) Fig. 20. Soil temperature in the final cover test section at White Mesa from 12/25/18 to 03/24/19 (sensor depths in mm bgs in legend, D = downslope; U = upslope). 0 10 20 30 40 50 12/20/18 1/5/19 1/22/19 2/8/19 2/25/19 3/14/19 3/31/19 White Mesa, UT Cu m u l a t i v e T i p s f o r R u n o f f Tipper (1 L) Fig. 21. Cumulative tips from tipper in the runoff basin for the final cover test section at White Mesa from 12/25/18 to 03/24/19. 18 0 100 200 300 400 500 12/20/18 1/5/19 1/22/19 2/8/19 2/25/19 3/14/19 3/31/19 White Mesa, UT Ru n o f f B a s i n S t a g e f o r R u n o f f ( m m ) Fig. 22. Pressure transducer stage in the runoff basin for the final cover test section at White Mesa from 12/25/18 to 03/24/19. 0.0 0.1 0.2 0.3 0.4 0.5 12/20/18 1/5/19 1/22/19 2/8/19 2/25/19 3/14/19 3/31/19 White Mesa, UT Cu m u l t i v e F l o w i n R u n o f f B a s i n ( m m ) Tipper (1-L) Pressure Transducer Fig. 23. Cumulative flow from pressure transducer stage and from the tipper for the final cover test section at White Mesa from 12/25/18 to 03/24/19. 19 0 2 4 6 8 10 12/20/18 1/5/19 1/22/19 2/8/19 2/25/19 3/14/19 3/31/19 White Mesa, UT Cu m u l a t i v e T i p s f o r L a t e r a l f l o w Tipper (1 L) Fig. 24. Cumulative tips from tipper in the lateral flow basin for the final cover test section at White Mesa from 12/25/18 to 03/24/19. 0 100 200 300 400 500 12/20/18 1/5/19 1/22/19 2/8/19 2/25/19 3/14/19 3/31/19 White Mesa, UT Pr e s s u r e T r a n s d u c e r S t a g e f o r L a t e r a l F l o w ( m m ) Fig. 25. Pressure transducer stage in lateral flow basin for the final cover test section at White Mesa from 12/25/18 to 03/24/19. 20 0.0 0.1 0.2 0.3 0.4 0.5 12/20/18 1/5/19 1/22/19 2/8/19 2/25/19 3/14/19 3/31/19 White Mesa, UT Cu m u l t i v e F l o w i n L a t e r a l F l o w B a s i n ( m m ) Tipper (1-L)Pressure Transducer Fig. 26. Cumulative flow from pressure transducer stage and from tipper in lateral flow basin for the final cover test section at White Mesa from 12/25/18 to 03/24/19. 0 1 2 3 4 5 12/20/18 1/9/19 1/29/19 2/18/19 3/10/19 3/31/19 White Mesa, UT Cu m u l a t i v e T i p s f o r D r a i n a g e Tipper (1 L) Tipper (70 mL) Fig. 27. Cumulative tips from the tipper in the drainage basin for the final cover test section at White Mesa from 12/25/18 to 03/24/19. 21 0 200 400 600 12/20/18 1/9/19 1/29/19 2/18/19 3/10/19 3/31/19 White Mesa, UT Pr e s s u r e T r a n s d u c e r S t a g e f o r D r a i n a g e ( m m ) Fig. 28. Pressure transducer stage in drainage basin for the final cover test section at White Mesa from 12/25/18 to 03/24/19. 0.0 0.1 0.2 0.3 0.4 0.5 12/20/18 1/5/19 1/22/19 2/8/19 2/25/19 3/14/19 3/31/19 White Mesa, UT Cu m u l t i v e F l o w i n D r a i n a g e B a s i n ( m m ) Tipper (70 mL)Pressure Transducer Tipper (1L) Fig. 29. Cumulative flow from pressure transducer stage and from tippers in drainage basin for the final cover test section at White Mesa from 12/25/18 to 03/24/19. 22 -4.0 -3.0 -2.0 -1.0 0.0 12/20/18 1/5/19 1/22/19 2/8/19 2/25/19 3/14/19 3/31/19 White Mesa, UT Va u l t S t a g e ( m m ) Fig. 30. Vault stage in the basin for the final cover test section at White Mesa from 12/25/18 to 03/24/19. 100 120 140 160 180 200 12/20/18 1/5/19 1/22/19 2/8/19 2/25/19 3/14/19 3/31/19 White Mesa, UT Va u l t V o l t a g e ( v o l t ) Fig. 31. Vault voltage in the basin for the final cover test section at White Mesa from 12/25/18 to 03/24/19. Q2-19 DATA QUALITY REPORT FOR THE PRIMARY TEST SECTION WHITE MESA MILL – TAILINGS MANAGEMENT CELL 2 ENERGY FUELS RESOURCES (USA) INC. SAN JUAN COUNTY, UTAH 18 July 2019 1 1.0 INTRODUCTION This data quality report (DQR) was prepared to record data quality assurance for the White Mesa Mill cover performance monitoring test section (Primary Test Section) for second quarter 2019 (Q2-19). This report is documentary and not interpretative. The annual report includes interpretation of the monitoring data. The Primary Test Section was constructed in August – September 2016 over tailings management Cell 2 at Energy Fuels Resources (USA) Inc.’s White Mesa Mill in San Juan County, Utah. Hydrological monitoring was initiated on 29 September 2016. A large-scale “ACAP-style” drainage lysimeter is used to monitor the test section. The lysimeter is equipped to monitor all water balance components along with meteorological data. Fig. 1 shows a profile of the final cover being evaluated at White Mesa (minimum thickness). Fig. 2 shows a cross-sectional schematic of the lysimeter. The test section is instrumented with two nests of vertically stacked and co-located sensors to monitor soil temperature and soil water content, as illustrated in Figs. 1 and 2. The nests are on the centerline of the test section at the upper and lower 1/3 points. Probes in the lower nest are odd-numbered and probes in the upper nest are even numbered. The water content probes were calibrated with on-site soils collected during construction. Temperature compensation was incorporated into the calibrations. Flows from the runoff, lateral flow (interflow), and percolation collection points in the test section are routed via pipe (Fig. 2) to collection basins in a subsurface vault downslope from the test section. Flow into each basin is monitored by tipping buckets and a pressure transducer. Flows reported by the tipping bucket are described in terms of “tips,” whereas water elevations reported by the transducers are reported as “stage.” Flows are reported in mm of water per unit area. The tipping buckets and pressure transducers were calibrated initially in September 2016, and re-calibrated on 10 May 2017, 14 November 2017, and 27 June 2018. 2.0 WATER BALANCE DATA Data in this DQR were collected during Q2-19 from 24 March 2019 to 24 June 2019. These dates align with automated data downloads and do not correspond precisely to the start and end of Q2-19. Data for 25 June 2019 and onward will be included in the Q3-19 report. Fig. 3 shows the water balance graph for the test sections and Table 1 summarizes the water balance quantities. Fig. 4 shows cumulative percolation and daily precipitation for both test sections. Figs. 5-31 show data from each sensor collected during Q2-19. The quality assurance summary is on pp. 7-8. The site received substantial precipitation in Q2-19, primarily as rain. However, precipitation during Q2-19 had little impact on water redistribution in the cover or water fluxes from the cover. Elevated water contents from infiltration of snow melt in the upper 1 m of the cover in Q1-19 diminished during Q2-19 (Figs. 13-15), as water was removed from the cover via evapotranspiration. At depths greater than 1 m below ground surface (bgs), the water contents remained relatively constant. A very small amount of runoff was measured (Fig 23). No lateral flow or percolation was recorded (Figs. 26, 29). 2 3.0 CONCERNS Significant differences in water content exist between Probes 1 and 2 and betweenProbes 3 and 4. These differences have existed since 2017 and are a response tolateral water movement above the compacted layer associated with infiltration of snowmelt in 2017. These differences are not a substantive concern and are diminishingslowly. Water contents reported by these probes will continue to be compared during future quality control activities. 4.0 ACTION ITEMS Continue comparison of water content Probes 1 and 2 and Probes 3 and 4. 3 Fig. 1. Schematic of cover profile evaluated at White Mesa. 4 Fig. 2. Schematic of lysimeter used for the White Mesa Primary Test Section. 5 Table 1. Water balance quantities for the final cover test section at White Mesa from 09/29/16 to 06/24/19. Calendar Year Water Balance Quantities (mm) Precipitation Runoff Lateral Flow ET  Storage Percolation 2016 59.9 0.03 0.00 34.6 16.9 0.00 2017 222.7 0.06 0.00 324.8 39.4 0.65 2018 163.4 0.09 0.00 124.6 37.9 0.90 2019 225.6 0.24 0.00 262.1 -35.4 0.03 *Flows not measured from 7 February 2017 to 25 March 2017 due to vault flooding. 6 0 200 400 600 800 0 200 400 600 800 9/20/16 3/7/17 8/23/17 2/8/18 7/27/18 1/12/19 6/30/19 White Mesa, UT Soil Water Storage On-Site Precipitation On-Site ET Surface RunoffPercolation NWS ET NWS Precipitation Lateral Flow So i l W a t e r S t o r a g e , C u m u l a t i v e R u n o f f , L a t e r a l F l o w , an d P e r c o l a t i o n ( m m ) Cu m u l a t i v e P r e c i p i t a t i o n a n d E v a p o t r a n s p i r a t i o n ( m m ) Fig. 3. Water balance quantities for the final cover test section at White Mesa from 09/29/16 to 06/24/19. 7 DATA QUALITY REPORT SUMMARY: Q2-19 White Mesa Primary Test Section 03/24/19 through 06/24/19 Water Balance Summary Table 1 summarizes the water balance of the test section since inception. Fig. 3 is the water balance graph for the test section since inception. Fig. 4 is a graph of daily precipitation and cumulative percolation for the test section since inception. Meteorology The battery and solar panel are working properly (Fig. 5). All meteorological sensors are working properly (Figs. 6-12). NWS precipitation data from the nearby Kane Gulch-Blanding (23WSW) station were used for the May and June 2019 data instead of data from the central Blanding station (KBDG, 37.62° N, 109.47° W, Elev.: 6001 ft). NWS data from the central Blanding station were unavailable during that period because the National Climatic Data Center was upgrading its website. The on-site precipitation data are consistent with, but slightly less than, the NWS data recorded during Q2-19 (Fig. 7). Most of the difference between the on-site and NWS precipitation occurred during two large storms, one in late April and the other in late May. The solar radiation data are consistent with data recorded at the NWS Blanding station (Fig. 12). Test Section The WCR probes to measure water content are functioning properly (Figs. 13-19). Differences in water content of approximately 0.2 are reported by Probes 3 and 4 in the compacted layer at 2134 mm bgs (Fig. 18). Differences in water content of approximately 0.1 are reported by Probes 1 and 2 in the interim layer at 2743 mm bgs (Fig. 19). These differences in water content reflect spatial variations in water content remaining from the deep penetration of a wetting front in Q1-17. The thermocouples used to measure soil temperature are functioning properly (Fig. 20). 8 Flows reported by the transducer and tippers for runoff, lateral flow, and percolation are reasonably consistent (Figs. 21-29). The vault stage has been negative, ranging from -2.0 to -3.0 mm, indicating no accumulation of water in the vault (Fig. 30). The voltage sensor that monitors the power supply in the vault is functioning properly (Fig. 31). No line power loss occurred during Q2-19. 9 0 10 20 30 40 50 0.0 0.5 1.0 1.5 2.0 9/20/16 3/7/17 8/23/17 2/8/18 7/27/18 1/12/19 6/30/19 Da i l y P r e c i p i t a t i o n ( m m ) Cu m u l a t i v e P e r c o l a t i o n ( m m ) White Mesa, UT Percolation Precipitation Fig. 4. Daily precipitation (blue) and cumulative percolation (red) for the final cover test section at White Mesa from 09/29/16 to 06/24/19. 10 11 12 13 14 3/20/19 4/6/19 4/23/19 5/10/19 5/27/19 6/13/19 7/1/19 Ba t t e r y ( V o l t s ) Fig. 5. Battery voltage for the datalogger at the final cover test section at White Mesa from 03/24/19 to 06/24/19. 10 3/20/19 4/6/19 4/23/19 5/10/19 5/27/19 6/13/19 6/30/19 -0. 5 10 15 Da i l y P r e c i p i t a t i o n ( m m ) 0 Fig. 6. Daily precipitation at the final cover test section at White Mesa from 03/24/19 to 06/24/19. 3/20/19 4/6/19 4/23/19 5/10/19 5/27/19 6/13/19 6/30/19 0 20 40 60 80 100 Cu m u l a t i v e P r e c i p i t a t i o n ( m m ) White Mesa Blanding Fig. 7. Cumulative precipitation at the final cover test section at White Mesa (blue) and the NWS stations in Blanding (red) from 03/24/19 to 06/24/19. 11 0 10 20 30 40 0 10 20 30 40 White Mesa, UT Ti p p e r P r e c i p i t a t i o n ( m m ) Geonor Precipitation (mm) Fig. 8. Precipitation measured from tipper and Geonor precipitation gauge at the final cover test section at White Mesa from 09/29/16 to 06/24/19. 3/20/19 4/6/19 4/23/19 5/10/19 5/27/19 6/13/19 6/30/19 Min Air Temp Avg. Air Temp Max Air Temp -10 0 10 20 30 40 Da i l y A i r T e m p e r a t u r e ( oC) Fig. 9. Daily air temperature at the final cover test section at White Mesa from 03/24/19 to 06/24/19. 12 3/20/19 4/6/19 4/23/19 5/10/19 5/27/19 6/13/19 6/30/19 Min RH Avg. RHMax RH 0 20 40 60 80 100 120 Da i l y R e l a t i v e H u m i d i t y ( % ) Fig. 10. Daily relative humidity at the final cover test section at White Mesa from 03/24/19 to 06/24/19. 0 2 4 6 8 10 3/20/19 4/6/19 4/23/19 5/10/19 5/27/19 6/13/19 6/30/19 Da i l y M e a n W i n d S p e e d ( m / s ) Fig. 11. Daily mean wind speed at the final cover test section at White Mesa from 03/24/19 to 06/24/19. 13 0 2000 4000 6000 8000 10000 3/20/19 4/6/19 4/23/19 5/10/19 5/27/19 6/13/19 6/30/19 So l a r R a d i a t i o n ( W - h r / m 2 ) White Mesa Blanding Fig. 12 Total daily solar radiation at the final cover test section at White Mesa (blue) and NWS Blanding station (red) from 03/24/19 to 06/24/19. 0.0 0.1 0.2 0.3 0.4 0.5 3/20/19 4/9/19 4/29/19 5/20/19 6/9/19 6/30/19 White Mesa, UT (457-mm Depth Topsoil Layer) Vo l u m e t r i c W a t e r C o n t e n t Probe 13 Probe 14 Fig. 13. Volumetric water content in the growth medium layer (457 mm bgs) of the final cover test section at White Mesa from 03/24/19 to 06/24/19. Odd numbered probe is downslope and even is upslope. 14 0.0 0.1 0.2 0.3 0.4 0.5 3/20/19 4/6/19 4/23/19 5/10/19 5/27/19 6/13/19 6/30/19 White Mesa, UT(685-mm Depth Growth Medium Layer) Vo l u m e t r i c W a t e r C o n t e n t Probe 11 Probe 12 Fig. 14. Volumetric water content in the growth medium layer (685 mm bgs) of the final cover test section at White Mesa from 03/24/19 to 06/24/19. Odd numbered probe is downslope and even is upslope. 0.0 0.1 0.2 0.3 0.4 0.5 3/20/19 4/6/19 4/23/19 5/10/19 5/27/19 6/13/19 6/30/19 White Mesa, UT (914-mm Depth Growth Medium Layer) Vo l u m e t r i c W a t e r C o n t e n t Probe 9 Probe 10 Fig.15. Volumetric water content in the growth medium layer (914 mm bgs) of the final cover test section at White Mesa from 03/24/19 to 06/24/19. Odd numbered probe is downslope and even is upslope. 15 0.0 0.1 0.2 0.3 0.4 0.5 3/20/19 4/6/19 4/23/19 5/10/19 5/27/19 6/13/19 6/30/19 White Mesa, UT(1524-mm Depth Compacted Layer) Vo l u m e t r i c W a t e r C o n t e n t Probe 8 Probe 7 Fig. 16. Volumetric water content in the compacted layer (1524 mm bgs) of the final cover test section at White Mesa from 03/24/19 to 06/24/19. Odd numbered probe is downslope and even is upslope. 0.0 0.1 0.2 0.3 0.4 0.5 3/20/19 4/6/19 4/23/19 5/10/19 5/27/19 6/13/19 6/30/19 White Mesa, UT(1829-mm Depth Compacted Layer) Vo l u m e t r i c W a t e r C o n t e n t Probe 6 Probe 5 Fig. 17. Volumetric water content in the compacted layer (1829 mm bgs) of the final cover test section at White Mesa from 03/24/19 to 06/24/19. Odd numbered probe is downslope and even is upslope. 16 0.0 0.1 0.2 0.3 0.4 0.5 3/20/19 4/6/19 4/23/19 5/10/19 5/27/19 6/13/19 6/30/19 White Mesa, UT(2134-mm Depth Compacted Layer) Vo l u m e t r i c W a t e r C o n t e n t Probe 4 Probe 3 Fig. 18. Volumetric water content in the compacted layer (2134 mm bgs) of the final cover test section at White Mesa from 03/24/19 to 06/24/19. Odd numbered probe is downslope and even is upslope. 0.0 0.1 0.2 0.3 0.4 0.5 3/20/19 4/6/19 4/23/19 5/10/19 5/27/19 6/13/19 6/30/19 White Mesa, UT(2743-mm Depth Interim Layer) Vo l u m e t r i c W a t e r C o n t e n t Probe 2 Probe 1 Fig. 19. Volumetric water content in the interim layer (2743 mm bgs) of the final cover test section at White Mesa from 03/24/19 to 06/24/19. Odd numbered probe is downslope and even is upslope. 17 . -10 0 10 20 30 40 3/20/19 4/6/19 4/23/19 5/10/19 5/27/19 6/13/19 6/30/19 White Mesa, UT 2743 mm D 2743 mm U 2134 mm D 2134 mm U 1829 mm D 1829 mm U 1524 mm D 1524 mm U 914 mm D 914 mm U 685 mm D 685 mm U 457 mm D 457 mm U So i l T e m p e r a t u e ( oC) 2743 mm (D) 457 mm (D) Fig. 20. Soil temperature in the final cover test section at White Mesa from 03/24/19 to 06/24/19 (sensor depths in mm bgs in legend, D = downslope; U = upslope). 0 1 2 3 4 5 3/20/19 4/6/19 4/23/19 5/10/19 5/27/19 6/13/19 6/30/19 White Mesa, UT Cu m u l a t i v e T i p s f o r R u n o f f Tipper (1 L) Fig. 21. Cumulative tips from tipper in the runoff basin for the final cover test section at White Mesa from 03/24/19 to 06/24/19. 18 0 100 200 300 400 500 3/20/19 4/6/19 4/23/19 5/10/19 5/27/19 6/13/19 6/30/19 White Mesa, UT Ru n o f f B a s i n S t a g e f o r R u n o f f ( m m ) Fig. 22. Pressure transducer stage in the runoff basin for the final cover test section at White Mesa from 03/24/19 to 06/24/19. 0.0 0.1 0.2 0.3 0.4 0.5 3/20/19 4/6/19 4/23/19 5/10/19 5/27/19 6/13/19 6/30/19 White Mesa, UT Cu m u l t i v e F l o w i n R u n o f f B a s i n ( m m ) Tipper (1-L)Pressure Transducer Fig. 23. Cumulative flow from pressure transducer stage and from the tipper for the final cover test section at White Mesa from 03/24/19 to 06/24/19. 19 0 1 2 3 4 5 3/20/19 4/6/19 4/23/19 5/10/19 5/27/19 6/13/19 6/30/19 White Mesa, UT Cu m u l a t i v e T i p s f o r L a t e r a l f l o w Tipper (1 L) Fig. 24. Cumulative tips from tipper in the lateral flow basin for the final cover test section at White Mesa from 03/24/19 to 06/24/19. 0 100 200 300 400 500 3/20/19 4/6/19 4/23/19 5/10/19 5/27/19 6/13/19 6/30/19 White Mesa, UT Pr e s s u r e T r a n s d u c e r S t a g e f o r L a t e r a l F l o w ( m m ) Fig. 25. Pressure transducer stage in lateral flow basin for the final cover test section at White Mesa from 03/24/19 to 06/24/19. 20 0.0 0.1 0.2 0.3 0.4 0.5 3/20/19 4/6/19 4/23/19 5/10/19 5/27/19 6/13/19 6/30/19 White Mesa, UT Cu m u l t i v e F l o w i n L a t e r a l F l o w B a s i n ( m m ) Tipper (1-L)Pressure Transducer Fig. 26. Cumulative flow from pressure transducer stage and from tipper in lateral flow basin for the final cover test section at White Mesa from 03/24/19 to 06/24/19. 0 1 2 3 4 5 3/20/19 4/6/19 4/23/19 5/10/19 5/27/19 6/13/19 6/30/19 White Mesa, UT Cu m u l a t i v e T i p s f o r D r a i n a g e Tipper (1 L)Tipper (70 mL) Fig. 27. Cumulative tips from the tipper in the drainage basin for the final cover test section at White Mesa from 03/24/19 to 06/24/19. 21 0 200 400 600 3/20/19 4/6/19 4/23/19 5/10/19 5/27/19 6/13/19 6/30/19 White Mesa, UT Pr e s s u r e T r a n s d u c e r S t a g e f o r D r a i n a g e ( m m ) Fig. 28. Pressure transducer stage in drainage basin for the final cover test section at White Mesa from 03/24/19 to 06/24/19. 0.0 0.1 0.2 0.3 0.4 0.5 3/20/19 4/6/19 4/23/19 5/10/19 5/27/19 6/13/19 6/30/19 White Mesa, UT Cu m u l t i v e F l o w i n D r a i n a g e B a s i n ( m m ) Tipper (70 mL)Pressure Transducer Tipper (1L) Fig. 29. Cumulative flow from pressure transducer stage and from tippers in drainage basin for the final cover test section at White Mesa from 03/24/19 to 06/24/19. 22 -4.0 -3.0 -2.0 -1.0 0.0 3/20/19 4/6/19 4/23/19 5/10/19 5/27/19 6/13/19 6/30/19 White Mesa, UT Va u l t S t a g e ( m m ) Fig. 30. Vault stage in the basin for the final cover test section at White Mesa from 03/24/19 to 06/24/19. 100 120 140 160 180 200 3/20/19 4/6/19 4/23/19 5/10/19 5/27/19 6/13/19 6/30/19 White Mesa, UT Va u l t V o l t a g e ( v o l t ) Fig. 31. Vault voltage in the basin for the final cover test section at White Mesa from 03/24/19 to 06/24/19. October 23, 2019 Sent VIA E-MAIL AND EXPRESS DELIVERY Mr. Ty L. Howard Director Division of Waste Management and Radiation Control 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 2l40 ww, .cncrgyfucls. om Re: Transmittal of Q3-19 Data Quality Report ("DQR") for the White Mesa Cell 2 Cover Test Section Monitoring Dear Mr. Howard: In accordance with the Stipulation and Consent Agreement ("SCA" dated February 23, 2017) between the Division of Waste Management and Radiation Control ("DWMRC") and Energy Fuels Resource (USA) Inc. ("EFRJ"), EFRI constructed a cover performance monitoring test section on Cell 2 in 2016 and initiated performance monitoring. This letter transmits the data quality report for monitoring data collected during the third quarter of 2019. This report is being provided to DWMRC for information only, as submittal of this report is not a requirement of the SCA since the official test section monitoring time period has not yet started. Please note that this report is for quality assurance only and does not provide interpretive information. Interpretive information is provided in annual reports. For your convenience, two hard copies of the report and two CDs, each containing a word searchable electronic copy of the files, will be mailed to DWMRC. If you should have any questions regarding this transmittal please contact me at 303-389-4134. :;;::/;� ENERGY FUELS RESOURCES (USA) INC. Kathy Weinel Quality Assurance Manager CC: David C. Frydcnlund Terry Slade Logan Shumway Scott Bakken Paul Goranson Q3-19 DATA QUALITY REPORT FOR THE PRIMARY TEST SECTION WHITE MESA MILL – TAILINGS MANAGEMENT CELL 2 ENERGY FUELS RESOURCES (USA) INC. SAN JUAN COUNTY, UTAH 16 October 2019 1 1.0 INTRODUCTION This data quality report (DQR) was prepared to record data quality assurance for the White Mesa Mill cover performance monitoring test section (Primary Test Section) for third quarter 2019 (Q3-19). This report is documentary and not interpretative. The annual report includes interpretation of the monitoring data. The Primary Test Section was constructed in August – September 2016 over tailings management Cell 2 at Energy Fuels Resources (USA) Inc.’s White Mesa Mill in San Juan County, Utah. Hydrological monitoring was initiated on 29 September 2016. A large-scale “ACAP” drainage lysimeter monitors the test section. The lysimeter is equipped to monitor all water balance components along with meteorological data. Fig. 1 shows a profile of the final cover being evaluated at White Mesa (minimum thickness). Fig. 2 shows a cross-sectional schematic of the lysimeter. The test section is instrumented with two nests of vertically stacked and co-located sensors to monitor soil temperature and soil water content, as illustrated in Figs. 1 and 2. The nests are on the centerline of the test section at the upper and lower 1/3 points. Probes in the lower nest are odd-numbered and probes in the upper nest are even numbered. The water content probes were calibrated with on-site soils collected during construction. Temperature compensation was incorporated into the calibrations. Flows from the runoff, lateral flow (interflow), and percolation collection points in the test section are routed via pipe (Fig. 2) to collection basins in a subsurface vault downslope from the test section. Flow into each basin is monitored by tipping buckets and a pressure transducer. Flows reported by the tipping bucket are described in terms of “tips,” whereas water elevations reported by the transducers are reported as “stage.” Flows are reported in mm of water per unit area. The tipping buckets and pressure transducers were calibrated initially in September 2016, and re-calibrated on 10 May 2017, 14 November 2017, 27 June 2018, and 11 September 2019. 2.0 WATER BALANCE DATA Data in this DQR were collected during Q3-19 from 24 June 2019 to 22 September 2019. These dates align with automated data downloads and do not correspond precisely to the start and end of Q3-19. Data for 23 September 2019 and onward will be included in the Q4-19 report. Fig. 3 shows the water balance graph for the test sections and Table 1 summarizes the water balance quantities. Fig. 4 shows cumulative percolation and daily precipitation for both test sections. Figs. 5-31 show data from each sensor collected during Q3-19. The quality assurance summary is on pp. 7-8. Approximately 15 mm of precipitation was received as rain in Q3-19. Total precipitation in 2019 (240 mm) is the highest annual precipitation recorded since monitoring began in 2016 (Table 1). Most of the Q3-19 precipitation was quickly returned to the atmosphere as evapotranspiration. A very small fraction was shed as runoff (less than 0.02 mm). No deep penetration into the cover prolife occurred, and water contents in the upper meter of the cover remained steady or diminished due to evapotranspiration. 2 No lateral flow was recorded (Fig. 26) in Q3-19. Percolation was transmitted at a steady rate throughout most of Q3-19 (Fig. 4), and began to tail in September as the thermal gradient diminished (Fig. 20). 3.0 CONCERNS •Significant differences in water content exist between Probes 1 and 2 and betweenProbes 3 and 4. These differences have existed since 2017 and are a response to lateral water movement above the compacted layer associated with infiltration ofsnowmelt in 2017. These differences are not a substantive concern. Water contents reported by these probes will continue to be compared during future quality control activities. •Line power to the vault was interrupted for a short period in mid-September due to theGFCI breaker being tripped. The red light sentry mounted on the cabinet at the weatherstation ceased emitting light, indicating that the power was interrupted. Site personnel observed that the sentry was not emitting light and reported that the line power wasout. The GFCI breaker was reset during the calibration and maintenance activity on 11 September 2019. The vault pump was also tested when the breaker was reset, and functioned properly. No power loss to the datalogger occurred during that period, asthe data acquisition system relies on battery power. Electrical service from the plant is only used as a backup for the datalogger, and to power the pump within the vault if water accumulates. 4.0 ACTION ITEMS •Continue comparing water content Probes 1 and 2 and Probes 3 and 4. •Request periodic surveillance by site personnel to confirm that line power to the vault is maintained as evinced by light emitted by the red light sentry mounted on the cabinetat the weather station. 3 Fig. 1. Schematic of cover profile evaluated at White Mesa. 4 Fig. 2. Schematic of lysimeter used for the White Mesa Primary Test Section. 5 Table 1. Water balance quantities for the final cover test section at White Mesa from 09/29/16 to 09/22/19. Calendar Year Water Balance Quantities (mm) Precipitation Runoff Lateral Flow ET D Storage Percolation 2016 59.9 0.03 0.00 34.6 16.9 0.00 2017 222.7 0.06 0.00 324.8 39.4 0.65 2018 163.4 0.09 0.00 124.6 37.9 0.90 2019 240.3 0.25 0.00 272.9 -34.8 0.75 *damage from vault flooding precluded measuring flows from 7 February 2017 – 25 March 2017. 6 Fig. 3. Water balance quantities for the final cover test section at White Mesa from 09/29/16 to 09/22/19. 0 200 400 600 800 0 200 400 600 800 9/20/16 3/23/17 9/23/17 3/26/18 9/26/18 3/29/19 9/30/19 White Mesa, UT Soil Water Storage On-Site Precipitation On-Site Evapotranspiration Surface RunoffPercolation NWS Evapotranspiration NWS Precipitation Lateral Flow VaultFlooded So i l W a t e r S t o r a g e , C u m u l a t i v e R u n o f f , L a t e r a l F l o w , an d P e r c o l a t i o n ( m m ) Cu m u l a t i v e P r e c i p i t a t i o n a n d E v a p o t r a n s p i r a t i o n ( m m ) 7 DATA QUALITY REPORT SUMMARY: Q3-19 White Mesa Primary Test Section 06/24/19 through 09/22/19 Water Balance Summary •Table 1 summarizes the water balance of the test section since inception. •Fig. 3 presents the water balance graph for the test section since inception. •Fig. 4 shows graphs of daily precipitation and cumulative percolation for the test section since inception. Meteorology •The battery and solar panel are working properly (Fig. 5). •All meteorological sensors are working properly (Figs. 6-12). •The on-site precipitation data are generally lower than the NWS data recorded at the Blanding station (KBDG, 37.62° N, 109.47° W, Elev.: 6001 ft) (Fig.7). However, independent precipitation measurements recorded by the Geonor gage and the tipping bucket are in good agreement (Fig. 8). •Solar radiation data are consistent with data recorded at the NWS Blanding station (Fig. 12). Test Section •The WCR probes to measure water content are functioning properly (Figs. 13-19). Differences in water content of approximately 0.2 are reported by Probes 3 and 4 in the compacted layer at 2134 mm bgs. Differences in water content of approximately 0.1 are reported by Probes 1 and 2 in the interim layer at 2743 mm bgs (Figs 18-19). These differences in water content are real and reflect spatial variations in water content that are remnant from the deep penetration of a wetting front in Q1-17. •The thermocouples used to measure soil temperature are functioning properly (Fig. 20). •Flows reported by the transducer and tippers for runoff, lateral flow, and percolation are reasonably consistent (Figs. 21-29). •The vault stage has been negative, ranging from -2.0 to -3.0 mm, indicating no accumulation of water in the vault (Fig. 30). The pump was tested on 11 September 2019 and functions properly. 8 •The voltage sensor that monitors the power supply in the vault is functioning properly (Fig. 31). An intermittent loss of line power occurred in early August. White Mesa personnel confirmed that there was a problem with the electrical service during that period. Another loss of line power occurred just prior to the calibration and maintenance activity on 11 September 2019. This line power loss was caused by the GFCI being tripped, and the sentry light on the datalogger cabinet showed the power was down. Line power to the vault was restored by re-setting the GFCI breaker. No power loss to the datalogger occurred during that period, as the data acquisition system relies on battery power. Electrical service from the plant is only used as a backup for the datalogger, and to power the pump within the vault if water accumulates. 9 Fig. 4. Daily precipitation (blue) and cumulative percolation (red) for the final cover test section at White Mesa from 09/29/16 to 09/22/19. Fig. 5. Battery voltage for the datalogger at the final cover test section at White Mesa from 06/24/19 to 09/22/19. 0 10 20 30 40 50 0.0 0.5 1.0 1.5 2.0 2.5 3.0 9/20/16 3/23/17 9/23/17 3/26/18 9/26/18 3/29/19 9/30/19 Da i l y P r e c i p i t a t i o n ( m m ) Cu m u l a t i v e P e r c o l a t i o n ( m m ) White Mesa, UT Percolation Precipitation 10 11 12 13 14 6/20/19 7/6/19 7/22/19 8/7/19 8/23/19 9/8/19 9/25/19 Ba t t e r y ( V o l t s ) 10 Fig. 6. Daily precipitation at the final cover test section at White Mesa from 06/24/19 to 09/22/19. Fig. 7. Cumulative precipitation measured at the final cover test section at White Mesa (blue) and NWS Blanding station (red) from 06/24/19 to 09/22//19. 6/20/19 7/7/19 7/24/19 8/10/19 8/27/19 9/13/19 9/30/19-0. 2 4 6 8 10 Da i l y P r e c i p i t a t i o n ( m m ) 0 6/20/19 7/7/19 7/24/19 8/10/19 8/27/19 9/13/19 9/30/19 0 5 10 15 20 25 Cu m u l a t i v e P r e c i p i t a t i o n ( m m ) White Mesa Blanding 11 Fig. 8. Precipitation measured from tipper and Geonor precipitation gauge at the final cover test section at White Mesa from 06/24/19 to 09/22/19. Fig. 9. Daily air temperature at the final cover test section at White Mesa from 06/24/19 to 09/22/19. 0 3 5 8 10 0 3 5 8 10 White Mesa, UT Ti p p e r P r e c i p i t a t i o n ( m m ) Geonor Precipitation (mm) 6/20/19 7/7/19 7/24/19 8/10/19 8/27/19 9/13/19 9/30/19 Min Air Temp Avg. Air Temp Max Air Temp -10 0 10 20 30 40 Da i l y A i r T e m p e r a t u r e ( oC) 12 Fig. 10. Daily relative humidity at the final cover test section at White Mesa from 06/24/19 to 09/22/19. Fig. 11. Daily mean wind speed at the final cover test section at White Mesa from 06/24/19 to 09/22/19. 6/20/19 7/7/19 7/24/19 8/10/19 8/27/19 9/13/19 9/30/19 Min RH Avg. RHMax RH 0 20 40 60 80 100 120 Da i l y R e l a t i v e H u m i d i t y ( % ) 0 2 4 6 8 10 6/20/19 7/7/19 7/24/19 8/10/19 8/27/19 9/13/19 9/30/19 Da i l y M e a n W i n d S p e e d ( m / s ) 13 Fig. 12 Total daily solar radiation at the final cover test section at White Mesa (blue) and NWS Blanding station (red) from 06/24/19 to 09/22/19. Fig. 13. Volumetric water content in the growth medium layer (457 mm bgs) of the final cover test section at White Mesa from 06/24/19 to 09/22/19. Odd numbered probe is downslope and even is upslope. 0 2000 4000 6000 8000 10000 6/20/19 7/7/19 7/24/19 8/10/19 8/27/19 9/13/19 9/30/19 So l a r R a d i a t i o n ( W - h r / m 2 ) White Mesa Blanding 0.0 0.1 0.2 0.3 0.4 0.5 6/20/19 7/10/19 7/30/19 8/20/19 9/9/19 9/30/19 White Mesa, UT(457-mm Depth Topsoil Layer) Vo l u m e t r i c W a t e r C o n t e n t Probe 13Probe 14 14 Fig. 14. Volumetric water content in the growth medium layer (685 mm bgs) of the final cover test section at White Mesa from 06/24/19 to 09/22/19. Odd numbered probe is downslope and even is upslope. Fig.15. Volumetric water content in the growth medium layer (914 mm bgs) of the final cover test section at White Mesa from 06/24/19 to 09/22/19. Odd numbered probe is downslope and even is upslope. 0.0 0.1 0.2 0.3 0.4 0.5 6/20/19 7/7/19 7/24/19 8/10/19 8/27/19 9/13/19 9/30/19 White Mesa, UT(685-mm Depth Growth Medium Layer) Vo l u m e t r i c W a t e r C o n t e n t Probe 11 Probe 12 0.0 0.1 0.2 0.3 0.4 0.5 6/20/19 7/7/19 7/24/19 8/10/19 8/27/19 9/13/19 9/30/19 White Mesa, UT (914-mm Depth Growth Medium Layer) Vo l u m e t r i c W a t e r C o n t e n t Probe 9 Probe 10 15 Fig. 16. Volumetric water content in the compacted layer (1524 mm bgs) of the final cover test section at White Mesa from 06/24/19 to 09/22/19. Odd numbered probe is downslope and even is upslope. Fig. 17. Volumetric water content in the compacted layer (1829 mm bgs) of the final cover test section at White Mesa from 06/24/19 to 09/22/19. Odd numbered probe is downslope and even is upslope. 0.0 0.1 0.2 0.3 0.4 0.5 6/20/19 7/7/19 7/24/19 8/10/19 8/27/19 9/13/19 9/30/19 White Mesa, UT(1524-mm Depth Compacted Layer) Vo l u m e t r i c W a t e r C o n t e n t Probe 8 Probe 7 0.0 0.1 0.2 0.3 0.4 0.5 6/20/19 7/7/19 7/24/19 8/10/19 8/27/19 9/13/19 9/30/19 White Mesa, UT(1829-mm Depth Compacted Layer) Vo l u m e t r i c W a t e r C o n t e n t Probe 6 Probe 5 16 Fig. 18. Volumetric water content in the compacted layer (2134 mm bgs) of the final cover test section at White Mesa from 06/24/19 to 09/22/19. Odd numbered probe is downslope and even is upslope. Fig. 19. Volumetric water content in the interim layer (2743 mm bgs) of the final cover test section at White Mesa from 06/24/19 to 09/22/19. Odd numbered probe is downslope and even is upslope. 0.0 0.1 0.2 0.3 0.4 0.5 6/20/19 7/7/19 7/24/19 8/10/19 8/27/19 9/13/19 9/30/19 White Mesa, UT(2134-mm Depth Compacted Layer) Vo l u m e t r i c W a t e r C o n t e n t Probe 4 Probe 3 0.0 0.1 0.2 0.3 0.4 0.5 6/20/19 7/7/19 7/24/19 8/10/19 8/27/19 9/13/19 9/30/19 White MEsa, UT(2743-mm Depth Interim Layer) Vo l u m e t r i c W a t e r C o n t e n t Probe 2 Probe 1 17 . Fig. 20. Soil temperature in the final cover test section at White Mesa from 06/24/19 to 09/22/19 (sensor depths in mm bgs in legend, D = downslope; U = upslope). Fig. 21. Cumulative tips from tipper in the runoff basin for the final cover test section at White Mesa from 06/24/19 to 09/22/19. 0 10 20 30 40 6/20/19 7/7/19 7/24/19 8/10/19 8/27/19 9/13/19 9/30/19 White Mesa, UT 2743 mm D 2743 mm U 2134 mm D 2134 mm U 1829 mm D 1829 mm U 1524 mm D 1524 mm U 914 mm D 914 mm U 685 mm D 685 mm U 457 mm D 457 mm U So i l T e m p e r a t u e ( oC) 2743 mm (D) 457 mm (D) 0 5 10 15 20 6/20/19 7/7/19 7/24/19 8/10/19 8/27/19 9/13/19 9/30/19 White Mesa, UT Cu m u l a t i v e T i p s f o r R u n o f f Tipper (1 L) Calibration 18 Fig. 22. Pressure transducer stage in the runoff basin for the final cover test section at White Mesa from 06/24/19 to 09/22/19. Fig. 23. Cumulative flow from pressure transducer stage and from the tipper in the runoff basin for the final cover test section at White Mesa from 06/24/19 to 09/22/19. 0 100 200 300 400 500 6/20/19 7/7/19 7/24/19 8/10/19 8/27/19 9/13/19 9/30/19 White Mesa, UT Ru n o f f B a s i n S t a g e f o r R u n o f f ( m m ) Calibration 0.0 0.1 0.2 0.3 0.4 0.5 6/20/19 7/7/19 7/24/19 8/10/19 8/27/19 9/13/19 9/30/19 White Mesa, UT Cu m u l t i v e F l o w i n R u n o f f B a s i n ( m m ) Tipper (1-L)Pressure Transducer 19 Fig. 24. Cumulative tips from tipper in the lateral flow basin for the final cover test section at White Mesa from 06/24/19 to 09/22/19. Fig. 25. Pressure transducer stage in lateral flow basin for the final cover test section at White Mesa from 06/24/19 to 09/22/19. 0 5 10 15 20 6/20/19 7/7/19 7/24/19 8/10/19 8/27/19 9/13/19 9/30/19 White Mesa, UT Cu m u l a t i v e T i p s f o r L a t e r a l F l o w Tipper (1 L) Calibration 0 100 200 300 400 500 6/20/19 7/7/19 7/24/19 8/10/19 8/27/19 9/13/19 9/30/19 White Mesa, UT Pr e s s u r e T r a n s d u c e r S t a g e f o r L a t e r a l F l o w ( m m ) Calibration 20 Fig. 26. Cumulative flow from pressure transducer stage and from tipper in lateral flow basin for the final cover test section at White Mesa from 06/24/19 to 09/22/19. Fig. 27. Cumulative tips from the tipper in the drainage basin for the final cover test section at White Mesa from 06/24/19 to 09/22/19. 0.0 0.1 0.2 0.3 0.4 0.5 6/20/19 7/7/19 7/24/19 8/10/19 8/27/19 9/13/19 9/30/19 White Mesa, UT Cu m u l t i v e F l o w i n L a t e r a l F l o w B a s i n ( m m ) Tipper (1-L)Pressure Transducer 0 500 1000 1500 2000 6/20/19 7/7/19 7/24/19 8/10/19 8/27/19 9/13/19 9/30/19 White Mesa, UT Cu m u l a t i v e T i p s f o r D r a i n a g e Tipper (1 L) Tipper (70 mL) 21 Fig. 28. Pressure transducer stage in drainage basin for the final cover test section at White Mesa from 06/24/19 to 09/22/19. Fig. 29. Cumulative flow from pressure transducer stage and from tippers in drainage basin for the final cover test section at White Mesa from 06/24/19 to 09/22/19. 0 200 400 600 6/20/19 7/7/19 7/24/19 8/10/19 8/27/19 9/13/19 9/30/19 White Mesa, UT Pr e s s u r e T r a n s d u c e r S t a g e f o r D r a i n a g e ( m m ) Calibration 0.0 0.2 0.4 0.6 0.8 1.0 6/20/19 7/7/19 7/24/19 8/10/19 8/27/19 9/13/19 9/30/19 White Mesa, UT Cu m u l t i v e F l o w i n D r a i n a g e B a s i n ( m m ) Tipper (70 mL) Pressure Transducer Tipper (1L) 22 Fig. 30. Vault stage in the basin for the final cover test section at White Mesa from 06/24/19 to 09/22/19. Fig. 31. Vault voltage in the basin for the final cover test section at White Mesa from 06/24/19 to 09/22/19. -4.0 -3.0 -2.0 -1.0 0.0 6/20/19 7/7/19 7/24/19 8/10/19 8/27/19 9/13/19 9/30/19 White Mesa, UT Va u l t S t a g e ( m m ) 100 120 140 160 180 200 6/20/19 7/7/19 7/24/19 8/10/19 8/27/19 9/13/19 9/30/19 White Mesa, UT Va u l t V o l t a g e ( v o l t ) February 4, 2020 Sent VIA E-MAIL A D EXPRESS DELIVERY Mr. Ty L. Howard Director Division of Waste Management and Radiation Control Utah Department of Environmental Quality 195 North 1950West P.O. Box 144880 Salt Lake City, UT 84114-4880 Energy Fuels Resources (USA) Inc. 225 Union Blvd. Suite 600 Lakewood, CO, S, 80228 303 974 2140 www.energyfuel .com Re: Transmittal of Q4-19 Data Quality Report ("DQR") for the White Mesa Cell 2 Cover Test Section Monitoring Dear Mr. Howard: In accordance with the Stipulation and Consent Agreement ("SCA" dated February 23, 2017) between the Division of Waste Management and Radiation Control ("DWMRC") and Energy Fuels Resource (USA) Inc. ("EFRI"), EFRI constructed a cover performance monitoring test section on Cell 2 in 2016 and initiated performance monitoring. This letter transmits the data quality report for monitoring data collected during the fourth quarter of 2019. This report is being provided to DWMRC for information only, as submittal of this report is not a requirement of the SCA since the official test section monitoring time period has not yet started. Please note that this report is for quality assurance only and does not provide interpretive information. Interpretive information is provided in annual rep011s. For your convenience, two hard copies of the report and two CDs, each containing a word searchable electronic copy of the files, will be mailed to DWMRC. If you should have any questions regarding this transmittal please contact me at 303-389-4134. ENERGY FUELS RESOURCES (USA) INC. Kathy Weinel Quality Assurance Manager CC: David C. Frydenlund Terry Slade Logan Shumway Scott Bakken Paul Goranson Q4-19 DATA QUALITY REPORT FOR THE PRIMARY TEST SECTION WHITE MESA MILL – TAILINGS MANAGEMENT CELL 2 ENERGY FUELS RESOURCES (USA) INC. SAN JUAN COUNTY, UTAH 25 January 2020 1 1.0 INTRODUCTION This data quality report (DQR) was prepared to record data quality assurance for the White Mesa Mill cover performance monitoring test section (Primary Test Section) for fourth quarter 2019 (Q4-19). This report is documentary and not interpretative. The annual report includes interpretation of the monitoring data. The Primary Test Section was constructed in August – September 2016 over tailings management Cell 2 at Energy Fuels Resources (USA) Inc.’s White Mesa Mill in San Juan County, Utah. Hydrological monitoring was initiated on 29 September 2016. A large-scale “ACAP” drainage lysimeter monitors the test section. The lysimeter is equipped to monitor all water balance components along with meteorological data. Fig. 1 shows a profile of the final cover being evaluated at White Mesa (minimum thickness). Fig. 2 shows a cross-sectional schematic of the lysimeter. The test section is instrumented with two nests of vertically stacked and co-located sensors to monitor soil temperature and soil water content, as illustrated in Figs. 1 and 2. The nests are on the centerline of the test section at the upper and lower 1/3 points. Probes in the lower nest are odd-numbered and probes in the upper nest are even numbered. The water content probes were calibrated with on-site soils collected during construction. Temperature compensation was incorporated into the calibrations. Flows from the runoff, lateral flow (interflow), and percolation collection points in the test section are routed via pipe (Fig. 2) to collection basins in a subsurface vault downslope from the test section. Flow into each basin is monitored by tipping buckets and a pressure transducer. Flows reported by the tipping bucket are described in terms of “tips,” whereas water elevations reported by the transducers are reported as “stage.” Flows are reported in mm of water per unit area. The tipping buckets and pressure transducers were calibrated initially in September 2016, and re-calibrated on 10 May 2017, 14 November 2017, 27 June 2018, and 11 September 2019. 2.0 WATER BALANCE DATA Data in this DQR were collected during Q4-19 from 22 September 2019 to 29 December 2019. These dates align with automated data downloads and do not correspond precisely to the start and end of Q4-19. Data for 30 December 2019 and onward will be included in the Q1-20 report. Fig. 3 shows the water balance graph for the test sections and Table 1 summarizes the water balance quantities. Fig. 4 shows cumulative percolation and daily precipitation for both test sections. Figs. 5-33 show data from each sensor collected during Q4-19. The quality assurance summary is on pp. 7-8. Approximately 70 mm of precipitation was received as rain in Q4-19, primarily in late November and December. Total precipitation in 2019 (308 mm) is the highest annual precipitation recorded since monitoring began in 2016 (Table 1). The Q4-19 precipitation was stored in the cover profile, shed as runoff (less than 0.05 mm, Fig. 24), or released by evapotranspiration (Fig. 3). Water contents increased to a depth of approximately 0.5 m. 2 No lateral flow was recorded (Fig. 28). Percolation tailed through mid-November and then ceased (Fig. 31). 3.0 CONCERNS • Significant differences in water content exist between Probes 1 and 2 and between Probes 3 and 4. These differences have existed since 2017 and are a response to lateral water movement above the compacted layer associated with infiltration of snowmelt in 2017. These differences are not a substantive concern. Water contents reported by these probes will continue to be compared during future quality control activities. • Line power to the vault was interrupted for two short periods in October, as confirmed with plant personnel. No power loss to the datalogger occurred during that period, as the data acquisition system relies on battery power. Electrical service from the plant is only used as a backup for the datalogger, and to power the pump within the vault if water accumulates. 4.0 ACTION ITEMS • Continue comparing water content Probes 1 and 2 and Probes 3 and 4. • Request periodic surveillance by site personnel to confirm that line power to the vault is maintained as evidenced by light emitted by the red light sentry mounted on the cabinet at the weather station. 3 Fig. 1. Schematic of cover profile evaluated at White Mesa. 4 Fig. 2. Schematic of lysimeter used for the White Mesa Primary Test Section. 5 Table 1. Water balance quantities for the final cover test section at White Mesa from 09/29/16 to 12/29/19. Calendar Year Water Balance Quantities (mm) Precipitation Runoff Lateral Flow ET  Storage Percolation 2016 59.9 0.03 0.00 34.6 16.9 0.00 2017* 222.7 0.06 0.00 324.8 39.4 0.65 2018 163.4 0.09 0.00 124.6 37.9 0.90 2019 307.9 0.28 0.00 324.8 3.3 1.01 *damage from vault flooding precluded measuring flows from 7 February 2017 – 25 March2017. 6 0 200 400 600 800 1000 0 1 2 3 4 5 9/1/16 3/22/17 10/11/17 5/2/18 11/21/18 6/12/19 1/1/20 Soil Water Storage On-Site Precip. On-Site ET Surface Runoff Percolation NWS ET NWS Precip. Lateral Flow So i l W a t e r S t o r a g e , C u m u l a t i v e P r e c i p i t a t i o n , an d C u m u l a t i v e E T ( m m ) Cu m u l a t i v e S u r f a c e R u n o f f , L a t e r a l F l o w , an d P e r c o l a t i o n ( m m ) Fig. 3. Water balance quantities for the final cover test section at White Mesa from 09/29/16 to 12/29/19. 7 4 DATA QUALITY REPORT SUMMARY: Q4-19 White Mesa Primary Test Section 09/22/19 through 12/29/19 Water Balance Summary Table 1 summarizes the water balance of the test section since inception. Fig. 3 presents the water balance graph for the test section since inception. Fig. 4 shows graphs of daily precipitation and cumulative percolation for the test section since inception. Meteorology The battery and solar panel are working properly (Fig. 5). All meteorological sensors are working properly (Figs. 6-12). The on-site precipitation data are generally consistent with the NWS data recorded at the Blanding station (KBDG, 37.62° N, 109.47° W, Elev.: 6001 ft) (Fig.7). Independent precipitation measurements recorded by the Geonor gage and the tipping bucket are also in good agreement (Fig. 8). Solar radiation data are consistent with data recorded at the NWS Blanding station (Fig. 12). Test Section The WCR probes to measure water content are functioning properly (Figs. 13-19). Differences in water content of approximately 0.2 are reported by Probes 3 and 4 in the compacted layer at 2134 mm bgs. Differences in water content of approximately 0.1 are reported by Probes 1 and 2 in the interim layer at 2743 mm bgs (Figs 18-19). These differences in water content are real and reflect spatial variations in water content that are remnant from the deep penetration of a wetting front in Q1-17. The thermocouples used to measure soil temperature are functioning properly (Fig. 20). Flows reported by the transducers and tippers for runoff, lateral flow, and percolation are reasonably consistent (Figs. 21-31). A decreasing trend in pressure transducer stage was recorded for the runoff and lateral flow basins (Figs.23 and 27), most likely due to temperature change or evaporation. 8 The vault stage has been negative, ranging from -2.0 to -3.0 mm, indicating no water accumulation in the vault (Fig. 32). The pump was tested on 11 September 2019 and functions properly. The voltage sensor that monitors the power supply in the vault is functioning properly (Fig. 33). Intermittent loss of line power occurred twice in mid-October. White Mesa personnel confirmed that there was a problem with the electrical service during that period. No power loss to the datalogger occurred during that period, as the data acquisition system relies on battery power. Electrical service from the plant is only used as a backup for the datalogger, and to power the pump within the vault if water accumulates. 9 0 10 20 30 40 50 0.0 0.5 1.0 1.5 2.0 2.5 3.0 9/20/16 4/8/17 10/25/17 5/14/18 11/30/18 6/18/19 1/5/20 Da i l y P r e c i p i t a t i o n ( m m ) Cu m u l a t i v e P e r c o l a t i o n ( m m ) White Mesa, UT Percolation Precipitation Fig. 4. Daily precipitation (blue) and cumulative percolation (red) for the final cover test section at White Mesa from 09/29/16 to 12/29/19. 10 11 12 13 14 9/15/19 10/3/19 10/22/19 11/10/19 11/28/19 12/17/19 1/5/20 Ba t t e r y ( V o l t s ) Fig. 5. Battery voltage for the datalogger at the final cover test section at White Mesa from 09/22/19 to 12/29/19. 10 9/15/19 10/3/19 10/22/19 11/10/19 11/28/19 12/17/19 1/5/20 -0. 2 4 6 8 10 Da i l y P r e c i p i t a t i o n ( m m ) 0 Fig. 6. Daily precipitation at the final cover test section at White Mesa from 09/22/19 to 12/29/19 9/15/19 10/4/19 10/22/19 11/10/19 11/29/19 12/17/19 1/5/20 0 20 40 60 80 Cu m u l a t i v e P r e c i p i t a t i o n ( m m ) White Mesa Blanding Fig. 7. Cumulative precipitation measured at the final cover test section at White Mesa (blue) and NWS Blanding station (red) from 09/22/19 to 12/29/19. 11 0 2 4 6 8 10 0246810 White Mesa, UT Ti p p e r P r e c i p i t a t i o n ( m m ) Geonor Precipitation (mm) Fig. 8. Precipitation measured from tipper and Geonor precipitation gauge at the final cover test section at White Mesa from 09/22/19 to 12/29/19. 9/15/19 10/3/19 10/22/19 11/10/19 11/28/19 12/17/19 1/5/20 Min Air Temp Avg. Air Temp Max Air Temp -20 -10 0 10 20 30 Da i l y A i r T e m p e r a t u r e ( oC) Fig. 9. Daily air temperature at the final cover test section at White Mesa from 09/22/19 to 12/29/19. 12 9/15/19 10/3/19 10/22/19 11/10/19 11/28/19 12/17/19 1/5/20 Min RHAvg. RH Max RH 0 20 40 60 80 100 120 Da i l y R e l a t i v e H u m i d i t y ( % ) Fig. 10. Daily relative humidity at the final cover test section at White Mesa from 09/22/19 to 12/29/19. 0 2 4 6 8 10 9/15/19 10/3/19 10/22/19 11/10/19 11/28/19 12/17/19 1/5/20 Da i l y M e a n W i n d S p e e d ( m / s ) Fig. 11. Daily mean wind speed at the final cover test section at White Mesa from 09/22/19 to 12/29/19. 13 0 2000 4000 6000 8000 10000 9/15/19 10/3/19 10/22/19 11/10/19 11/28/19 12/17/19 1/5/20 So l a r R a d i a t i o n ( W - h r / m 2 ) White Mesa Blanding Fig. 12. Total daily solar radiation at the final cover test section at White Mesa (blue) and NWS Blanding station (red) from 09/22/19 to 12/29/19. 0.0 0.1 0.2 0.3 0.4 0.5 9/15/19 10/7/19 10/29/19 11/21/19 12/13/19 1/5/20 White Mesa, UT (457-mm Depth Topsoil Layer) Vo l u m e t r i c W a t e r C o n t e n t Probe 13 Probe 14 Fig. 13. Volumetric water content in the growth medium layer (457 mm bgs) of the final cover test section at White Mesa from 09/22/19 to 12/29/19. Odd numbered probe is downslope and even is upslope. 14 0.0 0.1 0.2 0.3 0.4 0.5 9/15/19 10/3/19 10/22/19 11/10/19 11/28/19 12/17/19 1/5/20 White Mesa, UT (685-mm Depth Growth Medium Layer) Vo l u m e t r i c W a t e r C o n t e n t Probe 11 Probe 12 Fig. 14. Volumetric water content in the growth medium layer (685 mm bgs) of the final cover test section at White Mesa from 09/22/19 to 12/29/19. Odd numbered probe is downslope and even is upslope. 0.0 0.1 0.2 0.3 0.4 0.5 9/15/19 10/3/19 10/22/19 11/10/19 11/28/19 12/17/19 1/5/20 White Mesa, UT(914-mm Depth Growth Medium Layer) Vo l u m e t r i c W a t e r C o n t e n t Probe 9 Probe 10 Fig.15. Volumetric water content in the growth medium layer (914 mm bgs) of the final cover test section at White Mesa from 09/22/19 to 12/29/19. Odd numbered probe is downslope and even is upslope. 15 0.0 0.1 0.2 0.3 0.4 0.5 9/15/19 10/3/19 10/22/19 11/10/19 11/28/19 12/17/19 1/5/20 White Mesa, UT(1524-mm Depth Compacted Layer) Vo l u m e t r i c W a t e r C o n t e n t Probe 8 Probe 7 Fig. 16. Volumetric water content in the compacted layer (1524 mm bgs) of the final cover test section at White Mesa from 09/22/19 to 12/29/19. Odd numbered probe is downslope and even is upslope. 0.0 0.1 0.2 0.3 0.4 0.5 9/15/19 10/3/19 10/22/19 11/10/19 11/28/19 12/17/19 1/5/20 White Mesa, UT (1829-mm Depth Compacted Layer) Vo l u m e t r i c W a t e r C o n t e n t Probe 6 Probe 5 Fig. 17. Volumetric water content in the compacted layer (1829 mm bgs) of the final cover test section at White Mesa from 09/22/19 to 12/29/19. Odd numbered probe is downslope and even is upslope. 16 0.0 0.1 0.2 0.3 0.4 0.5 9/15/19 10/3/19 10/22/19 11/10/19 11/28/19 12/17/19 1/5/20 White Mesa, UT(2134-mm Depth Compacted Layer) Vo l u m e t r i c W a t e r C o n t e n t Probe 4 Probe 3 Fig. 18. Volumetric water content in the compacted layer (2134 mm bgs) of the final cover test section at White Mesa from 09/22/19 to 12/29/19. Odd numbered probe is downslope and even is upslope. 0.0 0.1 0.2 0.3 0.4 0.5 9/15/19 10/3/19 10/22/19 11/10/19 11/28/19 12/17/19 1/5/20 White Mesa, UT(2743-mm Depth Interim Layer) Vo l u m e t r i c W a t e r C o n t e n t Probe 2 Probe 1 Fig. 19. Volumetric water content in the interim layer (2743 mm bgs) of the final cover test section at White Mesa from 09/22/19 to 12/29/19. Odd numbered probe is downslope and even is upslope. 17 . 0 10 20 30 40 9/15/19 10/3/19 10/22/19 11/10/19 11/28/19 12/17/19 1/5/20 White Mesa, UT 2743 mm D 2743 mm U 2134 mm D 2134 mm U 1829 mm D 1829 mm U 1524 mm D 1524 mm U 914 mm D 914 mm U 685 mm D 685 mm U 457 mm D 457 mm U So i l T e m p e r a t u e ( oC) 2743 mm (D) 457 mm (D) Fig. 20. Soil temperature in the final cover test section at White Mesa from 09/22/19 to 12/29/19 (sensor depths in mm bgs in legend, D = downslope; U = upslope). 0 2 4 6 8 10 9/15/19 10/3/19 10/22/19 11/10/19 11/28/19 12/17/19 1/5/20 White Mesa, UT Cu m u l a t i v e T i p s f o r R u n o f f Tipper (1 L) Fig. 21. Cumulative tips from tipper in the runoff basin for the final cover test section at White Mesa from 09/22/19 to 12/29/19. 18 0 100 200 300 400 500 9/15/19 10/3/19 10/22/19 11/10/19 11/28/19 12/17/19 1/5/20 White Mesa, UT Ru n o f f B a s i n S t a g e f o r R u n o f f ( m m ) Fig. 22. Pressure transducer stage in the runoff basin for the final cover test section at White Mesa from 09/22/19 to 12/29/19. 90 95 100 105 110 9/15/19 10/3/19 10/22/19 11/10/19 11/28/19 12/17/19 1/5/20 White Mesa, UT Ru n o f f B a s i n S t a g e f o r R u n o f f ( m m ) Fig. 23. Pressure transducer stage in the runoff basin for the final cover test section at White Mesa from 09/22/19 to 12/29/19. 19 0.0 0.1 0.2 0.3 0.4 0.5 9/15/19 10/3/19 10/22/19 11/10/19 11/28/19 12/17/19 1/5/20 White Mesa, UT Cu m u l t i v e F l o w i n R u n o f f B a s i n ( m m ) Tipper (1-L)Pressure Transducer Fig. 24. Cumulative flow from pressure transducer stage and from the tipper in the runoff basin for the final cover test section at White Mesa from 09/22/19 to 12/29/19. 0 1 2 3 4 5 9/15/19 10/3/19 10/22/19 11/10/19 11/28/19 12/17/19 1/5/20 White Mesa, UT Cu m u l a t i v e T i p s f o r L a t e r a l F l o w Tipper (1 L) Fig. 25. Cumulative tips from tipper in the lateral flow basin for the final cover test section at White Mesa from 09/22/19 to 12/29/19. 20 0 100 200 300 400 500 9/15/19 10/3/19 10/22/19 11/10/19 11/28/19 12/17/19 1/5/20 White Mesa, UT Pr e s s u r e T r a n s d u c e r S t a g e f o r L a t e r a l F l o w ( m m ) Fig. 26. Pressure transducer stage in lateral flow basin for the final cover test section at White Mesa from 09/22/19 to 12/29/19. 45 46 47 48 49 50 9/15/19 10/3/19 10/22/19 11/10/19 11/28/19 12/17/19 1/5/20 White Mesa, UT Pr e s s u r e T r a n s d u c e r S t a g e f o r L a t e r a l F l o w ( m m ) Fig. 27. Pressure transducer stage in lateral flow basin for the final cover test section at White Mesa from 09/22/19 to 12/29/19. 21 0.0 0.1 0.2 0.3 0.4 0.5 9/15/19 10/3/19 10/22/19 11/10/19 11/28/19 12/17/19 1/5/20 White Mesa, UT Cu m u l t i v e F l o w i n L a t e r a l F l o w B a s i n ( m m ) Tipper (1-L)Pressure Transducer Fig. 28. Cumulative flow from pressure transducer stage and from tipper in lateral flow basin for the final cover test section at White Mesa from 09/22/19 to 12/29/19. 0 200 400 600 800 1000 9/15/19 10/3/19 10/22/19 11/10/19 11/28/19 12/17/19 1/5/20 White Mesa, UT Cu m u l a t i v e T i p s f o r D r a i n a g e Tipper (1 L) Tipper (70 mL) Fig. 29. Cumulative tips from the tipper in the drainage basin for the final cover test section at White Mesa from 09/22/19 to 12/29/19. 22 0 200 400 600 9/15/19 10/3/19 10/22/19 11/10/19 11/28/19 12/17/19 1/5/20 White Mesa, UT Pr e s s u r e T r a n s d u c e r S t a g e f o r D r a i n a g e ( m m ) Fig. 30. Pressure transducer stage in drainage basin for the final cover test section at White Mesa from 09/22/19 to 12/29/19. 0.0 0.2 0.4 0.6 0.8 1.0 9/15/19 10/3/19 10/22/19 11/10/19 11/28/19 12/17/19 1/5/20 White Mesa, UT Cu m u l t i v e F l o w i n D r a i n a g e B a s i n ( m m ) Tipper (70 mL) Pressure Transducer Tipper (1L) Fig. 31. Cumulative flow from pressure transducer stage and from tippers in drainage basin for the final cover test section at White Mesa from 09/22/19 to 12/29/19. 23 -4.0 -3.0 -2.0 -1.0 0.0 9/15/19 10/3/19 10/22/19 11/10/19 11/28/19 12/17/19 1/5/20 White Mesa, UT Va u l t S t a g e ( m m ) Fig. 32. Vault stage in the basin for the final cover test section at White Mesa from 09/22/19 to 12/29/19. 100 120 140 160 180 200 9/15/19 10/3/19 10/22/19 11/10/19 11/28/19 12/17/19 1/5/20 White Mesa, UT Va u l t V o l t a g e ( v o l t ) Fig. 33. Vault voltage in the basin for the final cover test section at White Mesa from 09/22/19 to 12/29/19. WHITE MESA URANIUM MILL CELL 2 RECLAMATION COVER 2019 ANNUAL PERFORMANCE MONITORING REPORT Appendix B 2019 REVEGETATION EVALUATION CELL 2 PRIMARY AND SUPPLEMENTAL TEST SECTIONS D White Mesa Mill Site 2019 REVEGETATION EVALUATION CELL 2 PRIMARY AND SUPPLEMENTAL TEST SECTIONS JANUARY 2020 CEDAR CREEK ASSOCIATES, INC. i Table of Contents 1.0 INTRODUCTION .......................................................................................................................... 1 1.1 General ................................................................................................................................... 1 1.2 Background ............................................................................................................................. 1 1.3 Precipitation ............................................................................................................................ 2 2.0 METHODS ................................................................................................................................... 3 3.0 2019 MONITORING RESULTS ...................................................................................................... 5 3.1 Primary Test Section ................................................................................................................ 5 3.2 Supplemental Test Section ....................................................................................................... 9 4.0 CONCLUSION ............................................................................................................................ 14 List of Tables & Exhibits Table 1 – 2019 Site and Long Term Average Precipitation ............................................................... 2 Figure 1 – Sampling Procedure ...................................................................................................... 4 Table 2 – Vegetation Cover - Primary Test Section - Spring Survey .................................................. 6 Table 3 – Vegetation Cover - Primary Test Section - Fall Survey ....................................................... 8 Table 4 – Summary of Woody Plant Density ................................................................................... 9 Table 5 – Vegetation Cover - Supplemental Test Section - Spring Survey ....................................... 11 Table 6 – Vegetation Cover - Supplemental Test Section - Fall Survey ............................................ 13 1 White Mesa Mill Site 2019 Revegetation Evaluation Cell 2 Primary and Supplemental Test Sections 1.0 INTRODUCTION 1.1 General Cedar Creek Associates, Inc. (Cedar Creek) was contracted to evaluate revegetation performance on the Primary and Supplemental Test Sections for the Cell 2 tailings management cell at the Energy Fuels Resources (USA) Inc. (EFRI) White Mesa Uranium Mill site (Mill Site). Mr. Jesse Dillon, from Cedar Creek, conducted an onsite evaluation of revegetation on the test sections at Mill site on May 29, 2019 and on September 11, 2019. This report summarizes field observations and presents full data analysis from the spring and fall evaluations. 1.2 Background The Primary Test Section was constructed in 2016 within the Cell 2 cover with seeding occurring at the optimal time in fall of 2016. The test section is approximately 100 feet by 100 feet, with a 32-feet by 64-feet lysimeter centered within the test section. The test section was constructed with the full-depth Cell 2 cover profile. During the 2017 field evaluation, Dr. Ed Redente identified good seedling emergence and establishment for revegetation in arid climates. Unfavorable spring precipitation conditions yielded poor revegetation performance during the spring evaluation in 2018. However, monsoonal precipitation in October yielded more favorable revegetation results in fall 2018. The assessment in 2019 represents the third growing season. The Supplemental Test Section was constructed and seeded in fall of 2017. The Supplemental Test Section was constructed as a supplemental vegetation monitoring section to the Primary Test Section and is not being used to evaluate the entire cover profile. The test section is 100 feet by 100 feet in size to match the dimensions of the Primary Test Section and is located to the north of the tailings management cells. Unfavorable spring precipitation conditions resulted in no seedling emergence during the spring 2 evaluation in 2018. However, plant emergence occurred in the fall of 2018 after monsoonal precipitation in October. The assessment in 2019 represents the second growing season. 1.3 Precipitation Precipitation conditions in the months prior to the 2019 revegetation evaluation have been favorable for plant growth. Regionally, the spring of 2019 can be considered a wet year with above average precipitation. Vegetation observed during the 2019 spring evaluation exhibited above average plant vigor and growth in response to favorable precipitation conditions. The spring months of March, April, and May are particularly important to plant growth and these months received 62.2 mm (233% of normal), 12.2 mm (55% of normal), and 36.7 mm (203% of normal) of precipitation respectively. January and February were also significantly above average, likely contributing to increased soil-moisture storage for plant utilization in the spring. Precipitation decreased substantially from June through October, within 25% or less than average precipitation recorded in each of those five months; this will affect the continued establishment of vegetation species adapted to summer and fall precipitation. Table 1 – 2019 Site and Long Term Average Precipitation 2019 Site Precipitation (mm) Blanding Long Term Average (mm) Percent of Normal (%) January 46.7 35.3 132% February 65.6 30.7 214% March 62.2 26.7 233% April 12.2 22.1 55% May 36.7 18.0 203% June 2.3 11.4 20% July 4.7 29.2 16% August 8.7 35.1 25% September 0.0 32.5 0% October 5.2 36.8 14% November 21.1 26.7 79% December 42.5 33.8 126% TOTAL 307.9 338.3 91% 3 2.0 METHODS The primary field effort called for sampling revegetated areas of the Primary and Supplemental Test Sections for ground cover and woody plant density. Due to the size of the test sections, sample points were determined in the field to preclude overlap. Woody plant density was determined only during the fall evaluation on the Primary Test Section using total enumeration. Cedar Creek traversed the revegetation unit in a systematic manner counting all shrubs encountered. Woody plant density only requires a single sampling each year due to the relatively slow change and stability in shrub populations. Woody plant density was sampled in the fall when herbaceous vegetation had started to senesce, allowing for easier location of the small, germinating shrubs. Ground cover at each sampling site was determined utilizing the point-intercept methodology as illustrated in Figure 1. First, a transect of 10 meters length was extended from the starting point of each sample site toward the direction of the next site to be sampled. Then, at each one-meter interval along the transect, a “laser point bar” was situated vertically above the ground surface, and a set of 10 readings were recorded as to hits on vegetation (noted by species), litter, rock (>2mm), or bare soil. Hits were determined at each meter interval by activating a battery of 10 specialized lasers situated along the bar at 10 centimeter intervals and recording the variable intercepted by each of the narrow (0.02”) focused beams (see Figure 1). In this manner, a total of 100 intercepts per transect were recorded resulting in 1 percent cover per intercept. This methodology and instrumentation facilitates the collection of the most unbiased, repeatable, precise, and cost-effective ground cover data possible. 4 Figure 1: Sampling Procedure Sample Site (Starting Point) • • • • • • • • • • Re vegetated Unit N • • • Laser I Point-Intercept Bar (Intercepts at 10 cm intervals - note path of" beams" for" hits" on ground cover) Note: 10 set-up points per transect with 10 intercepts per set-up point results in 100 intercepts per transect Laser Bar I~ !_ I / Laser Focused Beam (0.02' spot) (Special }., for Daylight Visibility)\ 1 I Hit recorded as to item/species ------ 5 3.0 2019 MONITORING RESULTS 3.1 Primary Test Section Spring Evaluation As noted in the 2018 monitoring report, the severe drought of the previous growing season resulted in near total senescence of vegetation in the spring of 2018. Precipitation improved in the fall of that year, which resulted in the slight increase of ground cover from perennial vegetation. This circumstance is not unique and has been observed on other projects where plants go dormant during a severe drought but regrow from the base when favorable precipitation conditions return, as occurred in 2019. Favorable precipitation conditions in the winter and spring of 2019 resulted in a substantial rebound in vegetation performance. The Primary Test Section was evaluated with 10 transects during the spring survey of the third growing season. Ground cover during the spring survey on the Primary Test Section consisted of 82.2% live vegetation, 1.1% rock, 3.5% litter, and bare ground exposure of 12.8% (Table 2). The following photos show the site conditions on the Primary Test Section during evaluation in the spring of 2018 compared with 2019. Spring 2018 Spring 2019 6 Table 2 White Mesa - Vegetation Cover - 2019 Primary Test Section - Spring Survey Percent Ground Cover Based on Point-Intercept Sampling Transect No.——> 1 2 3 4 5 6 7 8 9 10 Grasses P Agropyron smithii Western Wheatgrass 1 0.1 0.1 10 A Bromus tectorum Cheatgrass 1 0.1 0.1 10 P Elymus elymoides Squirreltail 61 63 52 56 49 55 35 59 43 38 51.1 61.9 100 Forbs A Descurainia pinnata Western Tansymustard 2 1 1 6 5 3 5 2.3 2.8 70 A Erodium cicutarium Redstem Stork's Bill 2 1 1 1 1 2 0.8 1.0 60 A Sisymbrium altissimum Tall Tumblemustard 31 23 36 39 42 9 27 21 14 40 28.2 34.1 100 Shrubs, Sub-shrubs, Cacti & Trees None 0.0 0.0 0 Total Plant Cover 95 89 88 96 92 71 68 84 64 79 Rock 0 1 0 0 1 1 2 2 3 1 Litter 1 5 6 2 3 6 6 4 0 2 Bare ground 4 5 6 2 4 22 24 10 33 18 Perennial Plant Cover 61 63 52 56 49 55 35 59 43 39 Plant Cover Mean =t= 1.38 n= 10 Variance =nmin = 1.1 3.5 12.8 51.2 Sample Adequacy Calculations:82.60 133.38 3.74 82.6 Average Cover Relative Cover Freq. Mean 7 Fall Evaluation Precipitation decreased substantially through the summer and into the fall, resulting in early senescence of herbaceous vegetation. The Primary Test Section was evaluated with 15 transects during the fall evaluation of the third growing season. Ground cover during the fall revegetation survey on Primary Test Section consisted of 65.9% live vegetation, 2.6% rock, 22.7% litter, and bare ground exposure of 8.8% (Table 3). Perennial plant cover across the unit averaged 51.9%, with annual species comprising 14.0%. The Primary Test Section did exhibit 24 fourwing saltbush (Atriplex canescens) across the whole seeded area (lysimeter and surrounding area), which equates to 105 stems per acre (Table 4). Due to the substantial growth of herbaceous vegetation in 2019, it was difficult to locate the small shrubs within the understory of perennial grasses, and it is anticipated the population is larger than measured. As shrubs continue to increase in size, shrub counts will become more accurate. Substantial grazing from jackrabbits has been recorded in the past, which likely affected the establishing population. However, the increased available forage in 2019 has likely negated much of the shrub predation, as no note of herbivory was noted on establishing shrubs in 2019. Primary Test Section – Fall Survey – September 11, 2019 8 Table 3 White Mesa - Vegetation Cover - 2019 Primary Test Section - Fall Survey Percent Ground Cover Based on Point-Intercept Sampling Transect No.——> 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Grasses P Agropyron smithii Western Wheatgrass 1 0.1 0.1 7 A Bromus tectorum Cheatgrass 8 0.5 0.8 7 P Elymus elymoides Squirreltail 69 69 58 60 52 49 57 52 43 33 56 52 46 32 36 50.9 77.2 100 Forbs A Descurainia pinnata Western Tansymustard 2 1 2 3 1 1 5 2 7 5 6 2.3 3.5 73 A Salsola tragus Russian Thistle 5 4 0.6 0.9 13 A Sisymbrium altissimum Tall Tumblemustard 7 2 3 7 8 19 4 19 34 13 13 6 9 14 10.5 16.0 93 Shrubs, Sub-shrubs, Cacti & Trees P Atriplex canescens Fourwing Saltbush 2 9 1 2 0.9 1.4 27 Total Plant Cover 78 73 63 70 61 68 63 67 62 72 70 67 59 52 64 Rock 2 1 0 0 0 3 2 3 4 1 2 3 7 8 3 Litter 15 22 27 27 27 23 23 20 28 20 21 20 19 25 23 Bare ground 5 4 10 3 12 6 12 10 6 7 7 10 15 15 10 Perennial Plant Cover 69 70 58 60 52 49 59 61 43 33 57 52 46 34 36 Plant Cover Mean =t=n = 15 Variance =nmin = 2.6 22.7 8.8 51.9 Sample Adequacy Calculations:65.93 1.35 41.07 1.71 65.9 Average Cover Relative Cover Freq. Mean 9 Table 4 Summary of Woody Plant Density Total Count Area ——> Lifeform Scientific Name Common Name Shrub Atriplex canescens Four-wing Saltbush 24 Woody Plants Per Acre 105 Primary Test Section 10 3.2 Supplemental Test Section Spring Evaluation The Supplemental Test Section was evaluated with 10 transects during the spring evaluation of the second growing season. Ground cover during the spring revegetation survey on Supplemental Test Section consisted of 74.5% live vegetation, 0.0% rock, 12.0% litter, and bare ground exposure of 13.5% (Table 5). Perennial plant cover across the unit averaged 4.0%, with annual species comprising 70.5%. This site was dominated by the weedy species redstem stork’s bill (Erodium cicutarium) and tumble mustard (Sisymbrium altissimum). These species are opportunistic following favorable growing season precipitation and made up approximately 95% of the total relative vegetation cover. Several desirable forb and grass (seeded) species were present in the understory and were not well captured by the quantitative sampling efforts in 2019. The consistent prevalence of desirable perennial species in the understory suggests seeded species should be a more significant part of the vegetation community in coming years. The following photos show the site conditions on the Supplemental Test Section during evaluation in the spring of 2018 compared with 2019. Spring 2018 Spring 2019 11 Table 5 White Mesa - Vegetation Cover - 2019 Supplemental Test Section - Spring Survey Percent Ground Cover Based on Point-Intercept Sampling Transect No.——> 1 2 3 4 5 6 7 8 9 10 Grasses P Agropyron smithii Western Wheatgrass 1 1 4 1 5 2 1 1.5 2.0 70 P Bouteloua gracilis Blue Grama 1 1 0.2 0.3 20 P Elymus cinereus Basin Wildrye 1 0.1 0.1 10 P Hilaria jamesii James' Galleta 2 2 0.4 0.5 20 P Muhlenbergia pauciflora New Mexico Muhly 1 1 1 0.3 0.4 30 Forbs P Achillea millefolium Common Yarrow 1 1 3 1 2 4 2 1.4 1.9 70 P Artemisia ludoviciana White Sagebrush 1 0.1 0.1 10 A Erodium cicutarium Redstem Stork's Bill 61 64 57 55 59 54 53 30 45 53 53.1 71.3 100 A Plantago patagonica Woolly Plantain 1 0.1 0.1 10 A Sisymbrium altissimum Tall Tumblemustard 10 9 9 4 19 10 22 37 20 33 17.3 23.2 100 Shrubs, Sub-shrubs, Cacti & Trees None 0.0 0.0 0 Total Plant Cover 73 75 68 68 80 69 80 76 70 86 Rock 0 0 0 0 0 0 0 0 0 0 Litter 10 14 11 9 7 13 16 16 15 9 Bare ground 17 11 21 23 13 18 4 8 15 5 Perennial Plant Cover 2 2 2 9 2 5 5 8 5 0 Plant Cover Mean =t= 1.38 n= 10 Variance =nmin = 74.5 Average Cover Relative Cover Freq. Mean 0.0 12.0 13.5 4.0 Sample Adequacy Calculations:74.50 36.94 1.27 12 Fall Evaluation Quantitative ground cover sampling metrics in the fall of 2019 did not detect additional perennial vegetation when compared with the spring effort, likely due to the unfavorable precipitation recorded during the summer and fall. The annual species prevalent at the site will act as nurse plants for the young perennials occupying the understory, and perennials should rebound if suitable precipitation occurs in the near future. The Supplemental Test Section was evaluated with 10 transects during the fall evaluation of the second growing season. Ground cover during the fall revegetation survey on Supplemental Test Section consisted of 79.4% live vegetation, 0.2% rock, 8.0% litter, and bare ground exposure of 21.4% (Table 6). Perennial plant cover across the unit averaged 2.0%, with annual species comprising 68.4%. Supplemental Test Section – Fall Survey – September 1, 2019 13 Table 6 White Mesa - Vegetation Cover - 2019 Supplemental Test Section - Fall Survey Percent Ground Cover Based on Point-Intercept Sampling Transect No.——> 1 2 3 4 5 6 7 8 9 10 Grasses P Agropyron smithii Western Wheatgrass 6 10 2 1 1.90 2.70 40 Forbs A Descurainia pinnata Western Tansymustard 1 0.1 0.1 10 A Erodium cicutarium Redstem Stork's Bill 47 50 40 37 57 54 41 28 22 37 41.3 58.7 100 A Sisymbrium altissimum Tall Tumblemustard 16 29 8 13 11 23 27 43 55 45 27.0 38.4 100 P Sphaeralcea coccinea Scarlet Globemallow 1 0.1 0.1 10 Shrubs, Sub-shrubs, Cacti & Trees None 0.0 0.0 0 Total Plant Cover 64 79 54 60 70 77 68 73 77 82 Rock 0 0 0 0 0 1 0 0 0 1 Litter 26 11 8 7 10 10 5 2 1 Bare ground 10 10 38 33 20 22 22 22 21 16 Perennial Plant Cover 1 0 6 10 2 0 0 1 0 0 Plant Cover Mean =t= 1.38 n = 10 Variance =nmin =3.11 0.2 8.0 21.4 2.0 Sample Adequacy Calculations:70.40 80.71 70.4 Average Cover Relative Cover Freq. Mean 14 4.0 CONCLUSION Following the revegetation evaluations in 2018, it was determined that the seeding of the Primary and Supplemental Test Sections were successful, although very low precipitation was observed for most of 2018. Favorable precipitation conditions in October 2018 allowed for late season plant growth, and very favorable conditions in the winter and spring of 2019 has facilitated a substantial increase in vegetation growth at the site, particularly on the Primary Test Section. The Supplemental section was younger during the 2018 drought when compared to the Primary Test section and has been slower to rebound. Qualitative observations not well detected by sampling metrics note that seeded perennial species are consistency found throughout the understory. The annual weedy species comprising most of the recorded ground cover will diminish over time and will act as nurse plants for younger seeded perennials. Barring a severe or prolonged drought, perennial species on the Supplemental Test Section should rebound once favorable precipitation returns, in a manner similar to what was observed on the Primary test section in 2019. The outlook for future years on the Primary Test Section is that plant cover of the seeded species should actually decrease once precipitation levels return to near average, leveling out between 30 to 40 percent, with about 40 percent cover as a maximum sustainable cover for this environment. The outlook for future years on the Supplemental Test Section is that plant cover of the seeded species should increase to about 15 to 25 percent in the third growing season in 2020 and to about 20 to 30 percent in the following years, with an eventual plant cover reaching about 40 percent as a maximum sustainable cover for this environment. This maximum cover for both test sections should stabilize in about seven years unless consecutive years of drought occur, and the trajectory for plant cover development is delayed. It is recommended that revegetation evaluation continue with spring and fall evaluations until plants are established in accordance with these expectations. The dynamic response to local precipitation conditions should be tracked until the revegetation community stabilizes. WHITE MESA URANIUM MILL CELL 2 RECLAMATION COVER 2019 ANNUAL PERFORMANCE MONITORING REPORT Appendix C CELL 2 SETTLEMENT MONITORING DATA D 5612 5614 5616 5618 5620 5622 5624 5626 5628 5630 5632 Dec-88 Dec-91 Dec-94 Dec-97 Dec-00 Dec-03 Dec-06 Dec-09 Dec-12 Dec-15 Dec-18 Dec-21 El e v a t i o n , f e e t m s l Figure C.1 White Mesa Mill Cell 2W1 Settlement Plate Measurements (1) (1) Note: (1) Settlement plate extended during Phase 1 cover construction. I ..... ---'I ' -- 5612 5614 5616 5618 5620 5622 5624 5626 5628 5630 5632 Dec-88 Dec-91 Dec-94 Dec-97 Dec-00 Dec-03 Dec-06 Dec-09 Dec-12 Dec-15 Dec-18 Dec-21 El e v a t i o n , f e e t m s l Figure C.2 White Mesa Mill Cell 2W2 Settlement Plate Measurements (1) Note: (1) Settlement plate extended during Phase 1 cover construction. I I _, --• I ' II 5612 5614 5616 5618 5620 5622 5624 5626 5628 5630 5632 Dec-88 Dec-91 Dec-94 Dec-97 Dec-00 Dec-03 Dec-06 Dec-09 Dec-12 Dec-15 Dec-18 Dec-21 El e v a t i o n , f e e t m s l Figure C.3 White Mesa Mill Cell 2W3 Settlement Plate Measurements (1) (1) Note: (1) Settlement plate extended during Phase 1 cover construction. I ~ II II II \ -T ,_ -• --J I 5612 5614 5616 5618 5620 5622 5624 5626 5628 5630 5632 Dec-88 Dec-91 Dec-94 Dec-97 Dec-00 Dec-03 Dec-06 Dec-09 Dec-12 Dec-15 Dec-18 Dec-21 El e v a t i o n , f e e t m s l Figure C.4 White Mesa Mill Cell 2W4 Settlement Plate Measurements (1) (1) Note: (1) Settlement plate extended during Phase 1 cover construction. I I • ~ ■L T -------T 5612 5614 5616 5618 5620 5622 5624 5626 5628 5630 5632 Dec-88 Dec-91 Dec-94 Dec-97 Dec-00 Dec-03 Dec-06 Dec-09 Dec-12 Dec-15 Dec-18 Dec-21 El e v a t i o n , f e e t m s l Figure C.5 White Mesa Mill Cell 2E1 Settlement Plate Measurements (1) (1) Note: (1) Settlement plate extended during Phase 1 cover construction. I 1111 1 -J ---' 5612 5614 5616 5618 5620 5622 5624 5626 5628 5630 5632 Dec-88 Dec-91 Dec-94 Dec-97 Dec-00 Dec-03 Dec-06 Dec-09 Dec-12 Dec-15 Dec-18 Dec-21 El e v a t i o n , f e e t m s l Figure C.6 White Mesa Mill Cell 2E1-N Settlement Plate Measurements (1) Note: (1) Settlement plate extended during Phase 1 cover construction. I --I 5612 5614 5616 5618 5620 5622 5624 5626 5628 5630 5632 Dec-88 Dec-91 Dec-94 Dec-97 Dec-00 Dec-03 Dec-06 Dec-09 Dec-12 Dec-15 Dec-18 Dec-21 El e v a t i o n , f e e t m s l Figure C.7 White Mesa Mill Cell 2E1-1S Settlement Plate Measurements (1) (1) Note: (1) Settlement plate extended during Phase 1 cover construction. I ~ I • -ii • 5612 5614 5616 5618 5620 5622 5624 5626 5628 5630 5632 Dec-88 Dec-91 Dec-94 Dec-97 Dec-00 Dec-03 Dec-06 Dec-09 Dec-12 Dec-15 Dec-18 Dec-21 El e v a t i o n , f e e t m s l Figure C.8 White Mesa Mill Cell 2E1-2S Settlement Plate Measurements (1) (1) (1) Note: (1) Settlement plate extended during Phase 1 cover construction. I , __ I I 11 I ,. I' - 5612 5614 5616 5618 5620 5622 5624 5626 5628 5630 5632 Dec-88 Dec-91 Dec-94 Dec-97 Dec-00 Dec-03 Dec-06 Dec-09 Dec-12 Dec-15 Dec-18 Dec-21 El e v a t i o n , f e e t m s l Figure C.9 White Mesa Mill Cell 2W7-C Settlement Plate Measurements Note: (1) Settlement plate had three feet of rod extended October 2014 month because interim cover was added in this area of Cell 2 (1) I --- -.. • 5612 5614 5616 5618 5620 5622 5624 5626 5628 5630 5632 Dec-88 Dec-91 Dec-94 Dec-97 Dec-00 Dec-03 Dec-06 Dec-09 Dec-12 Dec-15 Dec-18 Dec-21 El e v a t i o n , f e e t m s l Figure C.10 White Mesa Mill Cell 2W5-N Settlement Plate Measurements (1) (1) Note: (1) Settlement plate extended during Phase 1 cover construction. I 11 -... .. '' _I( - 5612 5614 5616 5618 5620 5622 5624 5626 5628 5630 5632 Dec-88 Dec-91 Dec-94 Dec-97 Dec-00 Dec-03 Dec-06 Dec-09 Dec-12 Dec-15 Dec-18 Dec-21 El e v a t i o n , f e e t m s l Figure C.11 White Mesa Mill Cell 2W3-S Settlement Plate Measurements (1) (1) Note: (1) Settlement plate extended during Phase 1 cover construction. I ·-- 11 .... ,I, ----■ 5612 5614 5616 5618 5620 5622 5624 5626 5628 5630 5632 Dec-88 Dec-91 Dec-94 Dec-97 Dec-00 Dec-03 Dec-06 Dec-09 Dec-12 Dec-15 Dec-18 Dec-21 El e v a t i o n , f e e t m s l Figure C.12 White Mesa Mill Cell 2W5-S Settlement Plate Measurements (1) (1) Note: (1) Settlement plate extended during Phase 1 cover construction. I ,...._ I I I' -T 5612 5614 5616 5618 5620 5622 5624 5626 5628 5630 5632 Dec-88 Dec-91 Dec-94 Dec-97 Dec-00 Dec-03 Dec-06 Dec-09 Dec-12 Dec-15 Dec-18 Dec-21 El e v a t i o n , f e e t m s l Figure C.13 White Mesa Mill Cell 2W7-N Settlement Plate Measurements (2) Notes: (1) Settlement plate had three feet of rod extended in October 2014 because interim cover was added in this area of Cell 2 (2) Settlement plate extended during phase 1 cover construction (1) I II 1" .... 5612 5614 5616 5618 5620 5622 5624 5626 5628 5630 5632 Dec-88 Dec-91 Dec-94 Dec-97 Dec-00 Dec-03 Dec-06 Dec-09 Dec-12 Dec-15 Dec-18 Dec-21 El e v a t i o n , f e e t m s l Figure C.14 White Mesa Mill Cell 2W7-S Settlement Plate Measurements (1) (1) Note: (1) Settlement plate extended during Phase 1 cover construction. I - .J --- 5612 5614 5616 5618 5620 5622 5624 5626 5628 5630 5632 Dec-88 Dec-91 Dec-94 Dec-97 Dec-00 Dec-03 Dec-06 Dec-09 Dec-12 Dec-15 Dec-18 Dec-21 El e v a t i o n , f e e t m s l Figure C.15 White Mesa Mill Cell 2W6-N Settlement Plate Measurements (1) (1) Note: (1) Settlement plate extended during Phase 1 cover construction. I - I I - 5612 5614 5616 5618 5620 5622 5624 5626 5628 5630 5632 Dec-88 Dec-91 Dec-94 Dec-97 Dec-00 Dec-03 Dec-06 Dec-09 Dec-12 Dec-15 Dec-18 Dec-21 El e v a t i o n , f e e t m s l Figure C.16 White Mesa Mill Cell 2W6-C Settlement Plate Measurements (1) (1) Note: (1) Settlement plate extended during Phase 1 cover construction. I - B I 1----• 5612 5614 5616 5618 5620 5622 5624 5626 5628 5630 5632 Dec-88 Dec-91 Dec-94 Dec-97 Dec-00 Dec-03 Dec-06 Dec-09 Dec-12 Dec-15 Dec-18 Dec-21 El e v a t i o n , f e e t m s l Figure C.17 White Mesa Mill Cell 2W6-S Settlement Plate (1) Note: (1) Settlement plate extended during Phase 1 cover construction. I 1r - --~ 5612 5614 5616 5618 5620 5622 5624 5626 5628 5630 5632 Dec-88 Dec-91 Dec-94 Dec-97 Dec-00 Dec-03 Dec-06 Dec-09 Dec-12 Dec-15 Dec-18 Dec-21 El e v a t i o n , f e e t m s l Figure C.18 White Mesa Mill Cell 2W5-C Settlement Plate (1) (1) Note: (1) Settlement plate extended during Phase 1 cover construction. I - I I -- ' 5612 5614 5616 5618 5620 5622 5624 5626 5628 5630 5632 Dec-88 Dec-91 Dec-94 Dec-97 Dec-00 Dec-03 Dec-06 Dec-09 Dec-12 Dec-15 Dec-18 Dec-21 El e v a t i o n , f e e t m s l Figure C.19 White Mesa Mill Cell 2W4-N Settlement Plate (1) (1) Note: (1) Settlement plate extended during Phase 1 cover construction. I I • ,,. - I .I. 5612 5614 5616 5618 5620 5622 5624 5626 5628 5630 5632 Dec-88 Dec-91 Dec-94 Dec-97 Dec-00 Dec-03 Dec-06 Dec-09 Dec-12 Dec-15 Dec-18 Dec-21 El e v a t i o n , f e e t m s l Figure C.20 White Mesa Mill Cell 2W4-S Settlement Plate Measurements (1) (1) Note: (1) Settlement plate extended during Phase 1 cover construction. I .. I I ---r· II WHITE MESA URANIUM MILL CELL 2 RECLAMATION COVER 2019 ANNUAL PERFORMANCE MONITORING REPORT Appendix D CELL 2 STANDPIPE PIEZOMETER WATER LEVELS D 5,590 5,595 5,600 5,605 5,610 5,615 Jun-16 Dec-16 Jun-17 Dec-17 Jun-18 Dec-18 Jun-19 Dec-19 Jun-20 Wa t e r L e v e l E l e v a t i o n ( f t ) Date Figure D.1 - Cell 2 Standpipe Piezometers Water Level Elevations C2-P01 C2-P02 C2-P03 C2-P04 C2-P05 C2-P06 C2-P07 C2-P08 C2-P09 C2-P10 C2-P11 C2-P12 C2-P13 C2-P14 C2-P15 C2-P16 C2-P17 C2-P18 C2-P19 C2-P20 C2-P21 C2-P22 C2-P23 Note (1): Pieozometer C2-P01 reading for Mar 20, 2019 was erroneous due to an issue with the water level meter (1) -....... --+---e-- 5,590 5,595 5,600 5,605 5,610 5,615 Jun-16 Dec-16 Jun-17 Dec-17 Jun-18 Dec-18 Jun-19 Dec-19 Jun-20 Wa t e r L e v e l E l e v a t i o n ( f t ) Date Figure D.2 - Cell 2 Standpipe Piezometers Water Level Elevations West Side of Cell (excluding locations near sump) C2-P01 C2-P02 C2-P03 C2-P04 C2-P05 C2-P06 C2-P07 C2-P08 (1) Note (1): Pieozometer C2-P01 reading for March 20, 2019 was erroneous due to an issue with the water level meter 5,590 5,595 5,600 5,605 5,610 5,615 Jun-16 Dec-16 Jun-17 Dec-17 Jun-18 Dec-18 Jun-19 Dec-19 Jun-20 Wa t e r L e v e l E l e v a t i o n ( f t ) Date Figure D.3 - Cell 2 Standpipe Piezometers Water Level Elevations Locations Near Sump C2-P09 C2-P10 C2-P11 C2-P12 C2-P14 C2-P15 C2-P16 --e---e- - 5,590 5,595 5,600 5,605 5,610 5,615 Jun-16 Dec-16 Jun-17 Dec-17 Jun-18 Dec-18 Jun-19 Dec-19 Jun-20 Wa t e r L e v e l E l e v a t i o n ( f t ) Date Figure D.4 - Cell 2 Standpipe Piezometers Water Level Elevations East Side of Cell (excluding locations near sump) C2-P13 C2-P17 C2-P18 C2-P19 C2-P20 C2-P21 C2-P22 C2-P23