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Home My WebLink AboutDRC-2001-001121 - 0901a06880adeb91INrnnNerro*o,) UnnNruu (us,r) ConponATroN Independence Plaza, Suite 950 . 1050 Seventeenth Street .Denver, CO 80265 . 303 628 7798 (main) . 303 389 aL25 (fax) September 7,2001 VIA HAND DELIVERY Mr. William J. Sinclair Director, Division of Radiation Control Utah Department of Environmental Quality P.O. Box 144850 168 North 1950 West Salt Lake City, UT 841l4-4850 Reference: Updated Topographic Map Ground Water Discharge Permit Application for White Mesa Mill Dear Mr. Sinclair: As promised in the June 22,2001, submittal from International Uranium (USA) Corporation ("IUSA") to the Division of Radiation Control ("DRC"), we are providing herewith updated copies of the topographic map of the White Mesa Millsite and the immediate suroundingarea. This map was generated from aerial photograplrs taken of the site on July 21 ,2001, and is a replacement for the map submitted as Attachment K to the June22 submittal. All of the current and historical monitoring wells have been added, as well as numerous other features requested by DRC. We are also providing updates to the survey information and listing of coordinates for specific features which were provided as Attachment L to the June 22 submittal. If you need additional copies of the map or have any questions, please feel free to contact me at (303) 389-4 I 60. Harold R. Roberts Vice President - Corporate Development cclatt:Larry Mize, UDEQ Division of Water Quality Loren Morton, UDEQ Division of Radiation Control R. William von Till, NRC Michelle R. Rehmann, IUSA Stewart J. Srnith Roman Pyrilr att: Dianne Nielson, UDEQ Dave Arrioti, S.E. Utah Health Department Ron F. Hochstein, IUSA David C. Frydenlund, IUSA cc w/out oooroilrte coordinates Misc. Features - White Mesa MillSite Revised using 2001 Topographic Map ( all coordinates are approximate ) Feature Eastiry_@_Tailings Cells - Appproximate Boundaries Cell No. Easting Northing 1-l NW 2577460 323190 NE 2579365 323145 sE 2579355 322078 sw 2576795 322150 A 2576880 322415 2 NW 2576795 922't5o NE 2580210 322040 sE 2580210 320745 sw 2576845 321680 NW 2576845 321680 NE 2580210 320745 sE 2579593 320100 sw 2576015 320825 4A NW 2577889 920411 NE 2579593 320100 sE 2578860 3t9021sw 2577469 319266 Water Well #1 2580084 Test Well 2580945 Jones Well 2581252 Jet Pump 2581250 Buin Spring 2574294 Cottonwood Spring 257OO24 WestwaterSpring 2574166 Former Leach Field (near office)NW 2580274 2580369 2580369sw 2580274 Old Leach Field (scale house) 323314 322687 318910 329460 310375 5391 317880 5238321692 5493 322228 322228 322128 322128 322279 322279 322223 322223 NE SE NW NE SE SW 2580765 2580786 2580786 2580765 Current Leach Field (east of Mill yard) NW NE SE SW 2581 040 2581 1 15 2581115 2581 040 2579420 2s79465 2579465 2579555 2579555 2579420 MW-13 2577590 MW-6-1 2578895 MW-6-2 2578895 MW-7-1 2578125 MW-7-2 2578125 MW-8-1 2577265 MW-8-2 2577265 D&M 3 2580092 D&M I 2581380 GH-94-1 2576459 GH-94-2t 2577257 GH-94-3 2577245 GH-94-4 2577365 D&M12 2578314D&M28 2577380 2581224 322530 2581324 322530 2581324 322370 2581224 322370 322915 322915 322785 322785 322645 322645 322400 322355 322175 322175 Land Fill NW NE SE SW Sedimentation Pond NW NE A B SE SW Lab Waste Holding Tank 2580085 322408 Abandoned Monitor Wells, Bore Holes, and Angle Holes Feature Easting Northing Elevation ( all coordinates are approximale ) 319547 5570320530 5588320530 5588 320886 5588320886 5588 320925 5590320925 5590 322720 5634.3 327365 s679.3 320549 5597320385 5585320046 5579319598 5572 326932 5648.1 317340 5547.6 09/06/2001 1:36 PM LAJlsisn Ausust zs,zooo srf,ev ( Adjusted to Local Elevation Datum ) Point No. Northing (Y) Easting (X) Elevation (Z) Description 459 318959.04 2578773.28 5584.66 CONTROL POINT 517 322140.21 2579468.12 5623.15 CONTROL POINT 523 320772.64 2576214.19 5608.22 CONTROL POINT 558 322415.34 2579590.24 5623.78 CONTROL POINT 16 325672.14 2579330.34 5645.76 GROUND 17 325671.85 2579330.42 5647.63 MONITOH WELL 1 18 328345.68 2583347.34 5671.39 WATER WELL 4 21 324491.93 2581423.30 5653.48 GROUND 22 324491.73 2581423.33 5654.96 MONITOR WELL 19 23 325121.59 2580133.00 5656.24 GROUND 24 325121.34 2580133.04 5657.5'l MONITOR WELL 1B 25 324168.39 2580424.68 5650.30 WATER WELL 2 26 320977.29 2581030.27 5619.93 GROUND27 320976.89 2581030.27 5621.40 TEMPORARY WELL 4-8 28 320863.28 2580890.44 5617.56 GROUND 29 320862.99 2580890.59 5618.58 TEMPORARY WELL 4-1 30 320988.62 2580872.88 5619.87 GROUND 31 320988.26 2580872.64 5621.O7 TEMPORARY WELL 4-7 32 320991.42 2s80905.88 5620.77 GROUND 33 320991.17 2580905.96 5622.33 MONITOR WELL 4 34 321115.77 2580916.23 5622.76 GROUND 35 321 1 15.39 2580916.1 1 5624.72 TEMPORARY WELL 4-2 36 321664.28 2580918.82 5631.21 GROUND 37 321663.86 2580918.88 5632.23 TEMPORARY WELL 4-3 38 321831.35 2580874.18 5636.11 GROUND 39 321831.07 2580874.19 5637.59 TEMPORARY WELL 4-9 40 322003.12 2580859.23 5638.75 GROUND 41 322002.88 2580859.24 5640.70 TEMPORARY WELL 4-5 42 323051.11 2579445.75 5629.71 WATER WELL 3 43 323113.81 2577189.09 5631.37 GROUND 44 3231'13.59 2577189.03 5632.78 MONITOR WELL 10-2 Page 1 OglO5l2OO14:01 PM LA].t?esign August 28,2ooo stev ( Adjusted to Loca! Elevation Datum ) Point No. Northing (Y) Easting (X) Elevation (Z) Description45 323107.20 2577185.50 5631.42 GROUND46 323106.77 2577185.65 5632.82 MONITOR WELL 10-1 47 322120.44 2576575.78 5618.38 GROUND48 322120.47 2576576.09 5619.66 MONITOR WELL 9-2 49 3221 15.09 2576580.78 5618.41 GROUND 50 322114.89 2576580.73 5619.88 MONITOR WELL 9-1 51 321969.75 2576210.03 561 1.23 GROUND 52 321969.45 2576209.93 5613.14 MONITOR WELL 2 54 321335.10 2578052.36 5612.52 1999-4 55 321050.98 2579124.47 5613.18 1999-1 56 320245.73 2578798.10 5608.51 GROUND 57 320245.47 2578798.10 5610.80 MONITOR WELL 11 58 319157.02 2578142.45 5598.13 GROUND 59 319156.70 2578142.39 5598.14 MONITOR WELL 14 60 319296.61 2577451.6461 319296.27 2s774s1.45 5599.18 GROUND5599.91 MONITOR WELL 15 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 320519.52 320519.12 320683.56 320683.29 320681.73 319821.19 319820.94 318453.61 318453.44 317341.02 317340.58 316871.92 316871.69 315491.01 315490.81 2577478.63 2577478.42 2576665.20 2576665.06 2576654.87 2576661.45 2576661.65 2578892.11 2578892.21 2576418.05 2576417.89 2574794.93 2574794.90 2576169.95 2s76169.80 5609.18 5608.97 5608.60 5609.15 5607.89 5585.53 5586.72 5573.81 5575.09 5552.88 5554.83 5560.52 5562.35 s539.11 5540.60 GBOUND MONITOR WELL 5 GROUND MONITOR WELL 12 Movement Moument 324 GROUND MONITOR WELL 16 GROUND MONITOR WELL 17 GROUND MONITOR WELL 3 GROUND MONITOR WELL 21 GROUND MONITOR WELL 20 Page 2 09105120014:01 PM Point No. Northinq (Y) LANDesign August 28,2000 Survey ( Adjusted to Local Elevation Datum ) Eastinq (X) Elevation (Z) Description 7B 79 80 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 1000 1 001 1 002 1 003 1 004 1 005 1 006 1007 1 008 1 009 1010 101 1 1012 1013 1014 1015 1016 1017 1018 1019 313968.87 2580980.87 5516.08 313968.74 2580981.05 5517.47 317984.21 2582422.92 GROUND MONITOR WELL22 WATER WELL 5 WM 42A wM 42 WM 43A WM 43 WM 22A wM 22 SE CELL 44 SW CELL 4A 323700.20 324139.62 324226.52 325394.68 319972.68 318980.24 319037.99 31931 1.68 2577927.29 2577358.60 2578536.75 2577857.34 2576120.10 2574710.18 2578787.27 2577402.54 320095.83 2579494.23 320771.26 2576221.47 319148.41 2577339.57 319345.61 2577230.88 31889s.65 2578685.49 319004.06 2578958.93 320448.27 2577840.87 320103.24 2579548.90 319348.60 2577465.23 320407.88 2578074.90 321335.34 2578568.19 322096.90 2579082.78 32059s.14 2580936.49 320594.77 2580936.51 320344.09 2580894.17 320343.83 2580893.58 320404.65 320477.53 320479.45 319353.88 321542.51 321510.94 321267.15 321258.88 321344.24 322095.83 322122.05 319008.34 2578088.47 2577645.60 2577634.29 2577472.34 2577283.95 2577394.83 2578377.73 2578406.93 2578566.48 2578065.20 2578066.87 2578876.42 5607.54 R.J. #66 5607.14 R.J. #133 5565.96 SW 17s',RP-S 5570.41 SW 175'RP-W 5584.66 SE 175'RP-S5581.36 SE 17s',RP-E 5608,22 NW CELL 4A 5607,48 NE CELL 4A 5598.77 5609.2'1 5611.79 5617.84 5612.30 5613.49 5607.33 5608.78 5609.75 5607.63 5607.84 5598.45 5612.40 5612.64 5612.72 5610.26 5611.89 5618.62 5620.34 5584.90 LEAK DETECTION CELL #4 LEAK DETECTION CELL #3 LEAK DETECTION CELL#2 LEAK DETECTION CELL #1 GROUND TEMPORARY WELL 4-4 GROUND TEMPORARY WELL 4-6 SLIME DRAIN CELL #3 CELL #3 CONTROL #1 CELL #3 CONTROL #2 SLIME DBAIN CELL #4 CONTROL POINT CELL #2 WEST CONTROL POINT FLANGE IN PVC CONTROL POINT NW COR SPILL\ SPILLWAY CREST SLIME DRAIN CELL #2 GROUND ROD SOUTH CELL #1 AERIAL PANEL S. CELL #1 AERIAL PANEL SE COR CELL #4 5578.78 5637.89 5623.42 5646.63 5643.11 5603.72 5574.66 5586.74 5572.39 Page 3 09/05120014:01 PM StateOf Utah e TYDEPARTMENT OF ENVIRONMENTAL QUALI DIVISION OF RADIATION CONTROL Michael O. LeavittGovemor Dianne R. Nielson. Ph.D.Executivc Dircctor William J. SinclairDirector TO: FROM: DATE: SUBJECT: MEMORANDUM Dane Finer t o"u f,f , LorenMorton /*b /L"Fr June27,2000 International Uranium Corporation White Mesa Uranium Tailings Facility: Engineering Design and As-Built Reports; Staff Findings, Conclusions, and Recommendations. 2. Executive Summaqv Review of engineering design plans, specifications and as-built reports provided by IUC have lead DRC staff to conclude that: 1.It is unlikely that any leak detection system exists under IUC wastewater disposal Cell l. Therefore, point of compliance groundwater monitoring wells will be required around Cell I in the Permit. Leak detection systems found urder IUC Cells 2 and 3 are grossly inadequate. Based on available systemdesign, geometry, andunderlyingbedrockpermeability, DRC staffestimate that flexible membrane liner (FML) leakage would remain undetected by the current system until leakage flows reach a rate of between 2,500 and 840,000 gaVauelday, with an average of about 200,000 gallacrelday. This lack of leak detection sensitivity fails to meet Utah Division of Water Quality (DWQ) performance standards for existing facilities (200 gaUacrelday). As a result, the existing design fails to comply with the DWQ Discharge Minimization Technology (DMT) requirements found in the GWQP Rules. Multiple lines of evidence also suggestthatthe 30-mil PVC membrane used as FML in Cells 1,2, and 3 is prone to excess leakage due to a number of factors, including: 1) suspect preparation of FML bedding and protective blanket layers, 2) lower PVC puncture strength, 3) higher PVC water vapor transmission, 4) long-term degradation of PVC membranes due to leaching ofplasticizer compounds and organic chemical attack, and 5) suspect PVC seam preparation and construction methods. As a result of leak detection system design shortcomings and suspect physical condition and integrity ofthe PVC FML in Cells 1,2 and3, a demonstration of adequate DMT will largely focus on performance of the final cover system, and to a lesser degree on operational improvements. Operational improvements, include, but are not limited to: l) additional J. 4. \ Memorandum June 27,2000 Page2 groundwater characterization and installation of new monitoring wells for each individual disposal cell,2) additional water quality monitoring parameters, 3) accelerated closure for Cell2, and 4) head minimizationefforts for Cells 2 and3. Improvements to the final cover include: decreased radon barrier permeability, addition of a high permeability filter zone and a FML/clay composite layer in the cover design, and shorter drainage path lengths. 5. Although the leak detection system design under Cell 4,{ represents an improvement over previous disposal cells at the facility, its leak detection shortcomings, and current state of neglect and disrepair mandate that this cell be retrofit to meet current Best Available Technology (BAT) standards before any use for tailings or wastewater disposal activities. 6. Lack of separate and independent construction supervision and construction quality control/quality assurance (CQA/QC) may have contributed to an increased rate of construction defects in IUC Tailings Cells 1, 2,3, and4. Revisions need to be made to any future IUC CQA/QC efforts andplansto ensuremodemconstructiontechniquesandprovide confidence in the engineering containment of new wastewater and tailings disposal cell construction. 7. An engineering survey error of approximately 900 feet has been discovered at tailings Cell 2, which must be resolved. Resolution of this error can be combined with surveys needed to correct other errors for the groundwater compliance monitoring wells. 8. An unlined sedimentation pond formerly drained the IUC mill site and ore storage pad area and has been used for on-site disposal of fly-ash. This Fly-Ash Pond is a potential source of groundwater pollution that needs to be investigated. Historical and ongoing operation of this Fly-Ash Pond constitutes a potential groundwater contamination source at the IUC facility. Appropriate measures to control groundwater pollution at this facility include, but are not limited to: 1) installation of an engineered cover system followed by point-of- compliance monitoring wells, or 2) removal of the fly-ash material and other contaminants and appropriated disposal at another approved and engineered facility. 9. Compliance with the GWQP Rules for issuance of a Permit to an existing facility at IUC can be achieved as described above. However, if groundwater contamination is discovered near Cells l, 2, or 3 during additional site characterization or installation of new groundwater monitoring wells, the Executive Secretary will not be able to affirm the lack of impairment of present and beneficial use without additional groundwater remediation measures. Introduction The purpose ofthis memorandum is to summarize DRC staff review and findings regarding five (5) reports provided by the International Uranium Corporation (IUC) regarding engineering design and construction ofwastewaterandtailings disposal cells atthe White Mesafacility nearBlanding, Utah. The five engineering reports reviewed by DRC staff are summarized in Table 1, below: o rneering Design and As-Built Reports Report Reference General Description June, 1979 D'Appolonia Consulting Engineers (DCE) Cells 1 and2 (1't Phase) engineering design report May, 1981 DCE Cell 3 (2"d Phase) engineering design report February, 1982 DCE Cells I and2 (1't Phase) construction "as-built" report March, 1983 Energy Fuels Nuclear Inc. (EFN) Cell 3 (2'd Phase) construction "as-built" report April 10, 1989 Umetco Minerals Corporation (Umetco) Cells 4A. and 48 engineering design report, amended. Includes: l) responses to NRC questions dated March 15, 1989, and 2) original August, 1998 Umetco report August, 1988 Umetco Original Umetco Cells 4A and 48 engineering design report September, 1996 Titan Environmental Tailings cover design, Cells I thru 4,{ Memorandum Jlurlre 27,2000 Page 3 Table l. Summary of IUC Review of these materials shows that engineering plans and construction "as-built" reports were provided by IUC for tailings Cells 1, 2, and 3. Unfortunately, no construction "as-built" report was provided for construction of Cell4. After review of the available engineering design plans, specifications, and construction "as-built reports, DRC staffhave made the following findings for each of the IUC tailings cells: General Findings l. Lack of Construction Documentation: Cell 1 - detailed review shows little information is available for the construction of tailings wastewater Cell I . The Febru ary,l9L2DCE Report states that EFN performed construction on both Cells I and 2, while DCE provided construction supervision services for only Cell2 (ibid., p. 3-l). Further the report goes on to state that the Cell 1 construction information provided in the report was fumished by EFN and not independently collected by DCE (ibid.). Unfortunately, Cell I construction information provided in the February, 1982 DCE report is limited to: final EFN Cell I excavation elevation contours (Figure l2), PVC liner test results (Appendix D), and 2 centerline profile cross-sections for the Cell 1 south and east dikes (Figure 2). No information is provided regarding several important construction elements such as: topsoil removal, soil and rock excavation methods, preparation of flexible membrane liner (FML) bedding materials, installation of leak detection or under drain systems, installation of the FML, or installation of a FML cover orprotective blanket layer. Memorandum June27,2000 Page 4 Based on the information available regarding construction of tailings wastewater Cell l, DRC staff conclude that: If Cell I was constructed as per its design, it appears the cell is underlain by a single FML. Without additional information regarding Cell 1 design and construction, DRC staff conclude that: No leak detection system (LDS) exists beneath Cell l, and Foundation materials found below the FML are likely to be of high permeability, either in the form of mechanically disturbed sandstone or crushed sandstone rubble. 2. Missing Cell 4 As-Built Report - no engineering "as-built" report was provided for the construction of Cell 4. As a result, DRC staff are currently unable to confirm if actual construction conformed to the April 10, 1989 Umetco design. However, this is not an urgent concern, in that IUC has agreed to refrain from using this disposal cell until it is retrofit to meet State requirements. However, in order to review the adequacy of any future IUC retrofit for Cell 4, it will be essential to have a thorough description of the existing construction for this cell. 3. Lack of Independent Construction Oualitv Assurance/Oualitv Control - of IUC Cells 1,2, and 3, only Cell 2hadconstruction quality assurance/quality control (CQA/QC) performed by an independentparty, andthen only forearthworkconstruction(2l82DEC Report, p.3-1). For Cells I and 3, IUC (EFN) personnel performed both earthwork construction and earthwork CQA/QC (Cell 1: ibid.; Cell 3: 3/83 EFN Report, p. 3-1). In a similar manner, FML installation and FML CQA/QC functions were also performed by the same party, i.e., the FML manufacturer for Cells I and2 (2182DCE Report, p. 3-5, and Cell 3 (3/S3 EFN Report, p.3-2). This lack of independent oversight for earthwork construction and FML installation increases the potential for construction flaws or shortcomings to have been overlooked or gone uncorrected. As a result, defects in the FML at Cells 1, 2, and 3 may exist which could cause a release of pollutants to the underlying groundwater and nearby environment. General Design Findings: Disposal Cells l. Mechanical Disturbance and Increased Foundation Permeabilitv - the bedrock formation found immediately below the tailings cells is the Dakota Sandstone. IUC field measurements indicate that the permeability of this bedrock formation ranges between 2.8 and944 ftlyr (2.71E-6to 9.128-4 cm/sec), with an average 237 fttyr (2.298-4 cm/sec), see Attachment l, below [DRC spreadsheet HydCond.XLS, tabsheet alldata, geologic formation Kdsl. B. 1) 2) Memorandum June 27,2000 Page 5 However, foundation preparation techniques used to prepare the final cell floor grade for Cells 2, and 3 included common soil excavation techniques, followed by mechanical ripping ofthe Dakota Sandstone bedrock for Cell 2 (}1S2DCE Report,p.3-2),and Cell 3 [3/83 EFN Report, p. 3-3]). It is also presumed that similar means were used to excavate the cell floor for tailings wastewater Cell 1. In some cases blasting was also used to remove excess bedrock materials, e.g. Cell 3, see March, 1983 EFN Report, page 3-3. In both cases, such disturbance will increase the permeability ofthe bedrock foundation located below the FML. As a result, the Dakota Sandstone permeabilities quoted by IUC must be considered minimum values for the pu{pose of estimating leak detection efficiency or leachate infiltration. 2. Inadequate Leak Detection System: Cells l. 2. and 3 - review of the IUC engineering design and as-built reports referenced above has lead DRC staff to the conclude that fluid under drain systems are inadequate as leak detection systems (LDS) at Cells l, 2, and 3. This conclusion is based on the following facts and observations: A. Lack of Engineering Design or Documentation at Cell 1 - none of the engineering design and as-built reports provided by IUC documents any type of permeable fluid collection layer located beneath the FML in tailings Cell I (5179 DCE Report, Sheets I thru 16, and 2182DCE Report, Figures 1,2, and 11). Consequently, DRC staff have conclude that no LDS exists at Cell 1. B. Poor Cell 2 and 3 LDS Design: Single Drain Pipe - no permeable fluid under drain layer is documented in the Cell 2 engineering design report (5179 DCE Report, Sheets I thru 16). However, brief description is provided in the text of the February, 1982 DCE As-Built Report of an "under drain" system constructed across the interior slope of the Cell2 south dike (2182 DCE Report, pp. 3-3 and 4). The most complete engineering design details for the "under drain" system are found in the Cell 3 design report, which states that this "under &ain" system is similar to that designed by IUC for Cell 2 and approved by NRC (5/81 DCE Report, p. 3-6). As a result, DRC staff conclude that an "under drain" system likely exists under the FML at both Cells 2 and 3. Engineering details for this "under drain" system show it is limited to a narrow layer of gravelly sand installed on the inside slope ofthe southern dike (5/81 DCE Report, Sheets 3 and 4). Said sand "under drain" layer is l-foot thick and was constructed with a perforated 3-inch diameter, perforated, PVC pipe at the inside toe of the south dike; hereafter, referred to as the "toe" drain (ibid.). This 3-inch "toe" drain apparently gravity drains to a central collection point where it is connected to a 1 foot diameterPVC riserpipe that extends up the interior slope underthe FML. This riser pipe access enables water to be removed from the "toe" drain and sand "under drain" layer by means of a pump. Memorandum Jwe27,2000 Page 6 C. It is clear from the engineering design drawings that the "under drain" system is confined to only the inside slope of the south dike, and does not extend urder any portion of the floor of either Cell 2 or 3. Furthermore, use of a single drain pipe in the LDS limits the detection of leaks to only those that may : 1) occur immediately over the "toe" drain pipe, or 2) flow at a leakage rate great enough to travel a significant horizontal distance to the "toe" drain. Such a design contributes to poor leak detection reporting time and efficiency, see discussions below. Lack of Permeabilitv Contrast Below FML to Collect and Divert Fluids For Detection: Cells 2 and 3 - no permeability information has been provided by IUC for soil materials constructed below the FML in Cells 2 or 3. However, available IUC soil gradation data allowed DRC staffto estimate the hydraulic conductivity ofthese materials, see Table 2, below. The average Dakota Sandstone bedrockpermeability is also provided below for comparison purposes. Review of this information shows that the "under drain" sand layer constructed along the inside slope of the southern dikes has a lower permeability than the FML bedding layer. Consequently, it is unlikely that FML leakage will be encouraged to flow into this layer unless high head conditions force it horizontally in that direction. Table2.Estrmated H ic Conductivity of Materials Below FM : IUC Cells 2 and 3 Layer Permeability tt) Layer Permeability {t) ftlday cm/sec ftlday cm/sec Cell Floor Cell Inside Sideslope (South Dike) FML Bedding 40 t.4tE-2 "Under drain"Blanket 20 7.068-3 Dakota Sandstone > 0.65 > 2.298-4 Footnote: l Permeability determined from IUC soil gradation data, as follows:A. FML Bedding Layer - from IUC grain size analysis chart in 2182DCEAs-Built Report, Figure 13; as determined from a U.S. Department of Transportation filter material permeability nomograph (Moulton, p.51). For details, see Attachment 3, below.B. Dakota Sandstone - average permeability from IUC test data, see Attachment l, below [DRC spreadsheet HydCond.XLS, tabsheet alldatq geologic formation Kdsl, where 237 ftlyr = 0.65 ff/day. This value is considered minimum permeability ofthe Dakota Sandstone bedrock due to mechanical fracturing and disturbance, see DRC discussion above.C. Under drain Blanket - from IUC design specifications provided in the 6/79 DCE Design Report, Appendix B, p. 4-2. No as-built soil gradation data were provided in ; as determined from a U.S. Department of Transportation filter material permeability nomograph (Moulton, p.51). For details, see Attachment 3, below. D. Long Reoorting Time Estimates: Cells 2 and 3 - it is important to consider LDS geometry in the soil layers immediately below the FML, in order to evaluate leak detection reporting time. At IUC Cell 3, FML leakage will first penneate the FML Bedding Layer, and if sufficient flow and head are available, may accumulate on the underlying bedrock. At this point, the time it takes a leak to report to the "toe" drain Memorandum June 27,2000 PageT for detection is a function ofi l) the permeability of these two materials,2) FML leakage flow rate and head, and 3) length and slope of the travel path the leak may take across the surface of the underlying bedrock material. To determine leak path length review of must be given to bedrock elevations and slope beneath the FML and "toe" drain location. Unfortunately, IUC has failed to document the total length or horizontal extent of the "toe" drain at Cell 3 (see 5/81 DEC Design Report, Sheets 2 and3). However, three IUC construction photographs suggests that the "toe" drain may extend across the entire length of the Cell 3 south dike (see 3/83 EFN As-Built Report, Appendix E, 2 photographs entitled "cell 3 under drain installation", and one entitled "Cell 3 under drain installation and bottom preparation"). This location is less than ideal, inthat FML leakage will have to travel across a long expanse of bedrock before reaching the "toe" drain. As explained below, seepage losses across this long travel path will result in undetected leakage from the facility. Shape and grade of the underlying bedrock formation under Cell 3 suggest that leakage from the eastern portion of Cell 3 will take a long western path followed by a shorter southem path to the "toe" drain; for a total distance of about 1,700 feet from the northeast corner of the cell floor (see 5/81 DCE Design Report, Sheet 2). A leak from the northwest cell floor corner would travel a path with nearly equal eastern and southern legs for a total distance of about 1,100 feet to reach the "toe" drain (ibid.). One simple method of estimating leak detection reporting time would be to assume: 1) that the FML Bedding Layer is saturated,2) that fluids in this layer travel at the same rate as the layer's permeability, estimated at 40 ftlday,3) ignore driving head and gradient for the leak, and 4) ignore seepage losses to the underlying bedrock layer as a result of horizontal travel to the "toe" drain. Using these very simple assumptions, leakage would take about 43 and 28 days to report from the eastern and westem leak paths mentioned above, respectively. Unfortunately, these can only be considered rough minimum estimates, in that for the FML BeddingLayerto become and be maintained saturated, alarge and continuous rate of leakage flow would be required thru the FML. Actual or more realistic estimates of leak reporting time may be orders of magnitude greater than 43 days. In any case, even the smallest simple assumption of 28 days is well beyond the EPA RCRA leak detection reporting time performance standard of I day (EpA, p. 8). Poor Leak Detection Efficiency - in order for leakage to find its way to the "toe" drain under Cell 3, the leakage flow rates thru the FML have to be greater than the seepage losses into the underlying bedrock. Only then can horizontal flow in the FML Bedding Layer be achieved. FML leakage rates below this value will not report to the "toe" drain, and will hence go undetected. E. Memorandum June 27,2000 Page 8 J. The lowest FML leakage rate needed for detection can be estimated from the permeability of the underlying Dakota Sandstone bedrock formation. IUC measurements of Dakota Sandstone permeability are listed in Attachment 1, and summarized in Table 3, below: Table 3. Summary of IUC Dakota Sandstone Permeability In-situ Borehole Tests Bedrock Permeability fl/Yr (t)gaVacrelday Maximum:944 842,173 Minimum:2.8 2,498 Average:237 211,442 Footnote: l) From DRC spreadsheet HydCond.XLS, tabsheet alldata (see Attachment l, below). In this case it is conservative to consider average permeability values in that IUC mechanically disturbed the Dakota Sandstone bedrock by ripping and blasting the foundations of Cells 2 and 3 (see discussion above). Based on the average bedrock permeability, itappearsthatthe FML leakage rate would needto reach about200,000 gallacrelday before fluids would appear in the "toe" drain for detection. Even under the lowest Dakota Sandstone permeability, the FML leakage rate would need to be greater than2,498 gaVacrelday in order for the "toe" drain to detect leakage. Both scenarios are dramatically greater than the EPA RCRA performance standard for leak detection effrciency (or sensitivity) of I gaUacrelday (EPA, p. 8). In conclusion, no as-built documentation for the Cell 1 LDS has been made available, consequently, DRC staJf can only conclude that no LDS exists at Cell 1. For Cells 2 and 3, the LDS systems are inadequate, because: 1) use of a single LDS pipe limits the ability of system to detect leaks unless they occur immediately over the pipe, or at high enough leakage rate to travel horizontally to the pipe, 2) diversion of leakage in a horizontal direction towards the "toe" drain is unlikely due to a lack of permeability contrast below the FML Bedding Layer,3) long travel paths underthe FML to the LDS drainage pipe greatly increase the time needed to detect a leak, on the order of at least 28 days or more, and 4) based on these considerations, leakage thruthe FML would likely be detected under Cells 2 or 3, only if the FML leakage rate exceeded about 200,000 gallacrelday. Inadequate Leak Detection System Design: Cell4,A. - some improvement was made in the design of the Cell 4.{ LDS, in that a network of pipes was devised under a larger portion of the cell's floor. This piping system was designed to gravity drain to the Southwest comer of Cell4,{, where a 12 inch access pipe would allow apump to remove any collected leakage fluid (8/88 Umetco Report, Sheet C4-4). However, detailed review also shows the Cell 44 LDS is also inadequate for the following reasons: Memorandum June 27,2000 Page 9 A. Lack of Permeabilitv Contrast to Divert Leachate to Collection Pipes - similar to Cells 1, 2, and 3, there is a lack of permeability contrast to direct or divert FML leakage to the LDS collection pipe network, based on: l) High Permeabilit), FML Bedding Layer - the FML bedding layer was designed to have a gradation of7|Yo sand and gravel and3}Yo fines passing the No. 200 sieve (8/88 Umetco Report, Attachment l, p.7). IUC claimed this bedding layer was "clayey", suggesting a lower permeability material that could possible force FML leakage horizontally towards the LDS collection pipe network (at the top of the FML bedding layer). However, based on a70Yo sand and gravel content, it is likely that this material has a high permeability. Furthermore, close review of the August, 1988 Umetco construction specifications shows that no permeability testing was required to documentthis material's hydraulic conductivity (ibid., Attachmentl). Nor was there any maximum permeability specification defined for this material. Consequently, DRC staff conclude that the permeability of this FML bedding material is likely high. 2) High Permeability Bedrock - the August, 1988 Umetco Report outlines that certain bedrock areas found to be soft will be over-excavated and replaced with ML or cl,-type soils (ibid., p. 8). However, this "spot" replacement does not provide a uniform layer of clay material across the final surface of the cell 4,{ floor excavation. Further, the August, 1988 Umetco design report also failed to stipulate permeability testing of the foundation materials to confirm hydraulic conductivity before placement of the FML bedding layer. It is also clear that IUC's practice was to mechanically rip and blast bedrock in order to achieve final grade (8/88 Umetco Report, Attachment I, p.3). Based on these considerations, it appears that much, if not all, ofthe bedrock surface under Cell4A was composed ofpermeable materials. Consequently, DRC staff also concluded that it is unlikely that a low permeability banier exists at the base of the FML bedding layer to collect leakage and convey it towards the LDS pipe network. Isolation of LDS Pioes by Secondar.v FML - the LDS design outlined in the August, 1988 Umetco Report calls for the LDS pipes to be installed in a FML lined trench, the base of which was to be located immediately over the bedrock foundation (ibid., Sheet C4-3). This secondary FML would extend away from the LDS trench a short distance, about I foot to either side. Also, the LDS collection pipe was to be installed over a thin granular bedding and under a subsequent backfill of granular material in the trench. B. Memorandum Jwrc 27,2000 Page 10 C. As a result of this geometry, any leakage from the uppermost or primary FML at a distant lateral location, that became perched on the bedrock material, would have to pass thru the secondary FML in order to be collected and removed via the LDS pipe network. Consequently, DRC staff concluded that the ability ofthe LDS design was limitedto detectionofleaks intheprimaryFML atlocationsthat immediately overlie the LDS collection pipe and secondary FML. Poor Leak Detection Efficiency - based on the above arguments, DRC staff concluded that the ability of the Cell 4A LDS to detect leaks is limited to the area immediately above the collection pipes and secondary FML, i.e., LDS area of influence. Taking this as a guide, an estimate of the LDS area of influence was calculated and compared with the total Cell 4A floor area, see Attachment 5, below. Based on these estimates, DRC staff concluded that the Cell 44. LDS design would only allow detection of leaks across about l.6Yo of the total floor area. Lack of coA/oc Testing for Seconda{v FML - the August, 1988 Umetco Design Report outlines the use of vacuum box testing of FML seams for the primary liner in cell4,{(ibid., AttachmentII, Procedure QC-I9-c4wM,p.2). unfortunately, this same specification excludes any such testing for the secondary FML in the LDS collection trenches (ibid.). As a result, less testing was performed on the secondary FML. Consequently, higher potential exists for flaws or defects to have gone undetected in the secondary FML, and more leakage to be released undetected from the Cell 4A LDS. Therefore, the leak detection efficiency of the Cell 4A. LDS, estimated above, is further reduced. In conclusion, DRC staff have also determined that the Cell 4A LDS is inadequate based on lack of permeability contrast to force leakage to the detection pipeage network, isolation of the LDS pipes by the limited secondary FML geometry, and poor detection efficiency caused by limited coverage and lesser scrutiny of secondary FML construction. Based on these findings, it appears that across about 98% ofthe Cell4,A' footprint, the sensitivity ofthe LDS is as equally poor as Cells 2 and 3; ranging from about 2,500 to 840,000 gallacrelday. Primary Purpose of "Under drain" Layer: Dike Stability - it is clear from the above discussion that the effectiveness of the Cell 2 and 3 leak detection systems is poor. Consequently, it is apparent that these design elements had a different engineering function. Review of the May, l98l DCE Report suggests that the primary purpose of these design elements was to minimize and control soil pore pressures in the south dike of each tailings cell in order to maximize dike stability (ibid., p.4-2). Appropriate Points-of-Compliance: Cells 1. 2. 3. and 4 - based on the above findings and evaluations, DRC staff conclude that: 1) no LDS exists under Cell 1 , and 2) the existing "toe" drain and "under drain" systems at Cells 2 and 3 are not adequate for purposes of leak detection monitoring. Since these three disposal cells have been in service for an extended period of time, and are full or at near full capacity of tailings and/or wastewater; little can be done to retrofit the existing facilities. Consequently, the Groundwater Discharge Permit D. 4. 5. Memorandum Jwrc 27 ,2000 Page 1l (Permit) must require IUC to install additional groundwater monitoring wells to measure local groundwater quality. In order to provide early warning, minimize both the time needed to detect groundwater pollution and clean it up, IUC must design and install a new groundwatermonitoring well networkthat includes monitoringwells around eachand every tailings disposal cell currently in service; i.e., Cells l, 2, and 3. In order to determine local groundwater flow directions, such wells must be installed both up and downgradient of each of these three tailings cells in question. Previously, IUC staff have expressed concems regarding possible difficulty to install new groundwater monitoring wells on the dikes between Cells I and2, and2 and 3. However, ieview of the IUC engineering design shows each of these dikes has a 20-foot crest width (6(79DCE Report, p. a-15). This is easily enough space for atruck-mounted drilling rig to drill and install the required monitoring wells. To avoid future traffic concems, the new wells can be completed with a flush protective cover that will allow vehicular traffic to pass over the wellheads. Additional evidence that monitoring wells can be installed on the dikes betweenthe cells is the factthatfive (5) ruC monitoring wells have alreadybeenconstructed on dikes at the facility, including: MW-5, MW- I I , and MW- I 2 (Cell 3 South dike, 3/83 EFN Report, Figure 1), and MW-14 and MW-I5 (Cell4 South dike,7l94 Titan Environmental Report, Figure 2.1). Unsatisfactory Plugging and Abandonment of Seven Wells Inside Cell 3 Footprint - the May, 1981 DCE Design Report explains how six (6) dry wells installed inside the footprint of Cell 3 will need to be plugged and abandoned before disposal cell construction; well pairs 6-1, 6-2,7'1,7-2,8'1, and 8-2 (ibid., p.5-2, and Figure 2). This report also calls for each well to be plugged by pumping grout into the well with use of a tremie pipe to ensure an adequate seal and a lack of air voids in the grout (ibid.). In contrast, the Cell 3 As-Built Report cites seven (7) wells that were abandoned, including the six (6) mentioned above, and a stockwater supply well (3/83 EFN Report, p.3-4). Unfortunately, this as-built report also discloses that no tremie pipe was used to plug these seven (7) wells. Instead the report explains how concrete was simply poured down each borehole and vibrated (ibid.). Such plugging and abandonment appears to be a violation of the Utah State Engineers Administrative Rules for Water Well Drillers, which requires initial placement of cement grouts at the bottom of the well with progressive upward placement, i.e.,thruatremiepipe[UtahAdministrativeCode(UAC)R655-4-12]. Asaresult,itappears that these wells have the potential to form vertical conduits for groundwater pollution from Cell3. Although it is too late to rectiff this mistake, it is all the more reason for individual groundwater quality monitoring to be done around each disposal cell, including Cell 3. Failure to Follow Specification for Dental Grouting of Bedrock Foundation Cracks - the May, 1981 DCE Cell3 Design Report called for "dental" grouting of cracks in the bedrock that were greater than 0.5 inch wide after cell excavation (ibid., Appendix B, p. 2-3). 6. 7. Memorandum Jwre27,2000 Page 12 However, the March, 1983 as-built report states that no "dental" grouting was undertaken, but instead that fractures in the bedrock were filled with washed sand (3/S3 EFN Report, p. 3-5). This failure to follow the prescribed engineering specification reinforces DRC staff interpretation, above, of high bedrock permeability for the Dakota Sandstone. 8. Unknown Plugging and Abandonment of Monitoring Well MW-13: Cell 4A Implications - the March, 1983 EFN As-Built Report for Cell 3 documents the installation of a monitoring well MW-13, located South of Cell 3 (ibid., Figure I and Appendix D). Comparison with other IUC drawings suggests this well was located in an area that later became the southwest corner of tailings Cell4.{ (8/88 Umetco Report, Figure 2.2-l). In fact, the July, 1994Titan Environmental Report does confirm that MW-13 was destroyed during construction of Cell 4A (ibid., Table 2.3). Although the location of MW-I3 is provided in the August, 1988 Umetco Report (Figure 2.2-l), no discussion is provided in the report if or how this well will be plugged and abandoned. No such mention is made in either the text of the Cell 4 Design Report or in the construction specifications regarding this matter (see 8/88 Umetco Report text and Attachment I [Plans and Specifications]). Consequently, it is not known if or how this well was plugged and abandoned prior to construction of Cell 4,{. As a result, the potential exists that well MW-13 could form a vertical conduit for groundwater pollution. To resolve this potential problem, DRC staff recommend the Permit be conditioned to require submittal of a plugging and abandonment report for MW-13 for DRC approval. If this report is found unacceptable, then the Permit should require corrective actions for excavation of the former well site and renewed efforts to adequately plug and abandon this well. 9. Error in Engineering Survey Coordinates: Need for New Survey - a discrepancy in local engineering survey coordinates has been discovered by DRC staff after review of the available engineering plans and as-built reports. Review of the June, 1979 DCE Report shows that the western margin of Cell 2 is located near an Easting grid coordinate of E 2,576,000 feet (ibid., Sheet 4). In contrast, the August, 1988 Umetco Report shows this same edge of Cell2 has different Easting coordinate of about 82,576,880 feet; an error of about 880 feet (ibid., Sheet C4-1). It appears this discrepancy can be explained only by an error in design or in construction. Consequently, IUC should be required to resolve this error by implementation of a Permit condition, that would require submiual and approval of a new reliable elevation survey of the facility to confirm and document location and elevation of all major features of the facility, including, but not limited to: dikes, pond spillways, monitoring wells, borings, pipelines, sedimentation ponds, nearby drainages, ore storage pads, milling facility, soil stockpiles, etc. This in order to comply with the requirements of the Utah Water Quality Design Requirements for Wastewater Collection, Treatment, and Disposal Systems [UAC Memorandum June27,2000 Page 13 R317-3-1.2(A)(l)1, this survey must be completed and sealed by a State licensed engineer or land surveyor. 10. Missing or Illegible Design Documents - review of the March, 1983 EFN Cell 3 As-Built Report found several maps and figures missing or illegible. IUC should be required to provide legible copies of the missing or illegible figures, as follows: 1) illegible Figures 2 (floor final excavation contour map) and 4 (slimes drain pipeage system layout), and 2) missing Figure 5 (screen analysis of tailings used as protective blanket and slimes drain media). Flexible Membrane Liner Findings 1. FML Bedding and Protective Blanket Concerns / Issues - IUC tailings Cells l, 2, and3 were lined with a PVC membrane. Review of available technical literature suggests that leakage may be expected from the PVC materials in question, due to several factors, as follows: A. Lack of Gradation Specifications for FML Bedding Materials: Fill Soils - review of two DCE engineering design reports shows that in areas where soil fill materials were to be added to achieve final grade, that no specifications were provided for the maximum bedding particle size for the subgrade below the FML for either Cells I and 2 (6179 DCE Report, Appendix B, pp. 2-9 and 2-5) or Cell 3 (5/81 DCE Report, Appendix B, pp. 2-8 and 2-5). As a result, over-size particles have the potential to cause point stresses that can lead to FML failure after loading; particularly if bedding material particles are angular in shape. B. Aneular Particles in FML Bedding Materials: Subgrade for Excavated Areas - construction specifications for Cells 1, 2, and 3 call for the Dakota Sandstone bedrock in certain areas to be excavated in order to achieve final design grade. In preparation of these areas, DCE construction specifications call for the following activities before FML installation (Cells I andZ: 6lTgDCEReport, Appendix B, pp. 2-5 md 2-10; Cell 3: 5/81 DCE Report, Appendix B, pp. 2-5,2-6, ard2-9): 1) Mechanical disturbance ofDakota Sandstone bedrock, including ripping and blasting.2) Crushing of subgrade materials with multiple passes of the treads of a crawler-type tractor for subgrade materials (where 20%o of the particles exceed 5 inches in diameter).3) Specifications for subgrade preparation to ensure:a) a final surface free of any particle or rock over 6 inches in diameter.b) "smooth" final slope with no pieces or fragments protruding more than 4 inches from the plane of excavation. These very liberal IUC specifications allow a subgrade surface with multiple areas of large angular rock fragments that could have easily punctured the PVC liner. Memorandum June27,2000 Page 14 2. However, as-built records suggest that bedding material particle size may have not been as large as once planned, in that one gradation test of the bedding material beneath Cell 2 indicates that the maximum particle size was less than 1.5 inches (2|82DCE Report, Figure 13, D1o0: 1.5 inch, Deo:0.75 inch, etc.). Unfortunately, no other gradation test result have been provided by IUC for the bedding material under any of the other tailings disposal cells at the White Mesa facility. It is important to note test pad research conducted at another Utah waste disposal landfill facility has shown that angular rocks of a size range of 0.25 to 1.0 inch in diameter, placed on subgrades in intimate contact with FMLs, have caused perforations in the overlying membrane liners under loads of 4,500 to 4,800 lb/ff (personal communication, Blake Robertson, Utah Division of Solid and Hazardous Waste). DRC have estimated static loads on the FML at IUC Cells 2,th1rr4, and found they appear to be less than 4,500 lblff, see Attachment2, below. However, IUC has provided little information regarding specific types of equipment used to construct the tailings cells. As a result, it is possible that dynamic loads during construction of the IUC tailings cells could have been equivalent to the test pad research in question, and thereby generated equivalent FML damage. C. Particle Size. Angularitv. and Placement Methods for Overl),ing Protective Blankets - review of the IUC construction specifications shows that after installation of the FML, that a protective soil blanket was installed in Cells 2 and3 (Cell 2: 6179DCE Report, Appendix 8,p.3-7 and2lS2DCE Report, pp. 3-5 and 3-6; Cell 3: 3/83 EFN Report, p. 3 -7 and 3 -8). For Cell 2, engineering specifi cations for this material called for use of soils excavated from the cell, with a maximum diameter of 3 inches (ibid.). For Cell 3, specifications called for use of coarse sand tailings (5/81 DCE Report, AppendixB,pp.3-7).Howevertheas-builtreportdocumentsotherwiseandexplains that excavated soils were also used for soil protective blanket over 70Yo of the Cell 3 liner (3/83 EFN Report, p.3-7 and 3-8). For both cells, the soil protective blankets were installed over the FML after construction of a temporary access ramp, with the use of trucks, front-end loaders, and small dozers (ibid.). However, no information was provided in any of the engineering design or the as-built reports to document the weight of the equipment used to place and spread the soil protective blanket. Nor were any calculations made to estimate any dynamic stress applied to the FML by this equipment. Consequently, the potential damage could have occurred to the Cell2 FML during placement of these materials without detection by IUC or its construction contractors. FML Puncture Prevention and Performance - currently standardized tests exist to measure the puncture performance of FML materials in response to a load applied over pointed obj ect or probe, e.g. ASTM Method 4833. The purpose of such a test is to determine the maximum load that a FML may be subjected to without puncture, and thereby design and control construction conditions and static and dynamic loads to prevent FML damage. Memorandum June 27,2000 Page 15 Review of the IUC engineering design reports shows that no FML puncture tests were conducted on any of the PVC FML materials installed in either Cells 1 and2 (6179 DCE Design Report, Appendix B, p. 3-3; and2l82 DCE As-Built Report, Appendix D) or Cell 3 (5/81 DCE Report, Appendix B, p. 3-3; and 5/83 EFN As-Built Report, Appendix B). Neither was any such testing planned for Cell4 (8/88 Umetco Design Report, Attachment II, Procedure QC-19-C4WM). As a result, it appears that little effort was employed by IUC to prevent perforations of the FML by static or dynamic loads during tailings cell construction. Consequently, it is reasonable to expect that puncture damage did occur during construction; resulting in a number of imperfections and/or perforations in the PVC liner under all four (4) IUC tailings cells. It is also important to note that in general, PVC membranes exhibit lower puncture strength (2.2lblmil) than High Density Polyethylene (HDPE) liners (2.8 lb/mil, see EPA, p. 31, Table 3-2). Consequently, all other factors being equal, a greater degree of FML puncture damage is expected under IUC tailings Cells 1,2, and3, in that these facilities were constructed with a 30-mil PVC liner (Cells I &2:2l82DcBReport, p.3-5 and Appendix D; Cell 3: 5/83 EFN Report, pp. 3-6 and 7). In contrast, Cell 4 was apparently completed with a 40-mil HDPE linerandmayhave experienced lesserpuncture damage during its construction (8/88 Umetco Design Report, Attachment I, p. 13). 3. PVC Liner Material Design Concems / Issues - at least three concems are apparent at the selection of PVC material as the FML of choice at the IUC tailings facility, as follows: A. High Water Vapor Permeability and Unmeasured Discharge to Environment - technical literature indicates that a 30-mil PVC membrane without defects will dischargewater atarateof 1.93 gallacrelday duetowatervaportransmissionalone (Koemer, p.369,Table 5.2). Unfortunately, this leakage rate is greaterthanthe EPA RCRA de-minimus leakage rate (l .0 gaUacre/day, see EPA, p. 30). It is also interesting to note that the PVC membrane water vapor permeability is 2-orders of magnitude higher than an equivalent thickness of HDPE liner (Koern er,p.369,Table 5.2). In fact, PVC membranes have the highest water vapor permeability of the five (5) different FML media cited (ibid.). Consequently, even under the best of circumstances, use of PVC liner technology at the IUC facility is not equivalent to EPA RCRA minimum technology guidance; nor does it constitute a de-minimus type discharge under said regulations. B. Long-Term Integritv ofPVC Liners - the long-termperformance orphysical integrity of PVC liners to contain tailings contaminants over long periods oftime is a concern, based on at least two (2) concerns listed below: 1) Effects of Plasticizer Leaching - plasticizer compounds added by the manufacture to PVC membranes leach from the FML over time (Koerner, p. 510). such leaching leads to progressive brittleness and cracking of pvc membranes (ibid., p. 393). Consequently, the long-term performance ofpVC Memorandum Jwe27,2000 Page 16 membranes may deteriorate with time; leading to increased rates of liner failure and leakage to the environment. Other synthetic membranes appear to have longer longevity than PVC materials (ibid., p. 510). 2) Poor Resistance to Chemical Attack by Organic Compounds - one technical reference cites PVC membranes has having generally poor chemical resistance in the presence of: aliphatic and aromatic hydrocarbons, chlorinated solvents, and crude petroleum solvents (Koerner, p. 3S9). IUC uses large amounts ofkerosene fuel in its uranium solvent extractionprocess, about 1,680 lblday (5l28l99IUC Groundwater Information Report, p. A-8). Unfortunately, kerosene contains both aliphatic and aromatic hydrocarbons. Two aromatic hydrocarbons (toluene and naphthalene), and one chlorinated solvent (chloroform) have also been detected in IUC tailings wastewater samples (7194Titan Environmental Report, Appendix B, Table l, slimes drain). As a result, deterioration should be expected in the PVC membranes below IUC tailings cells l, 2, and 3 as a result of interaction with these chemicals. Said deterioration could encourage formation of membrane defects and resulting discharge to the environment. 4. PVC Seam Construction Concerns/Issues - although the FML liners were installed by the manufacturer or their representatives, no detailed descriptions are provided by these parties in any of the IUC as-built reports (Cells I & 2:2182DCE Report, p. 3-5; Cell 3: 5/83 EFN Report, p. 3-6). Neither are any detailed descriptions provided for PVC liner seam constructioninCells l,2,or 3 inthelUCengineeringdesignreports(Cells I &2:6179DCE Report, pp.4-18 and 19, orAttachmentB specifications onp.3-5; Cell3: 5/81 DCEReport, pp. 3-4 and 5, or Attachment B specifications on p. 3-5). As a result, little is known about several critical factors related to integrity ofthe PVC liner system. Also, other issues are of concem regarding liner seam design and construction, as follows: A. PVC Seam Design and Specifications: Zones of Inherent Weakness - it is common for FML seams to be weaker than the geomembrane itself, largely because field construction techniques cannot match controlled factory conditions used by the liner manufacturer (Koemer,p.374). At IUC Cells 1, 2, and 3, field seam strength was also found to be lower than the virgin PVC material; where engineering design and specifications that required only an S}Yotear strength criteria for field manufactured seams relative to the virgin PVC panel material (Cells I & 2: 6179 DCE Report, Appendix B, p. 3-2; and Cell 3: 5l8l DCE Report, Appendix B, p. 3-2). IUC construction test data confirms this in that the seams constructed were weaker than the virgin PVC material, see Table 4, below. Contrary to the discussion above, factory manufactured seams in IUC Cells 1, 2, and 3 fared even worse than their field manufactured counterparts. Unfortunately, no explanation was provided in any of the IUC construction as-built reports. DRC staff can only speculate that either different tests were used, thereby rendering the results Memorandum Jwrc27,2000 Page 17 B. uncomparable; orthatthe factory made seams were actually of poor quality. In any case, both types of liner seams in Cells l,2,and 3 constitute apparent zones of weakness in the FML system that should have been accounted for in design of the FML system to withstand static and dynamic loads. Apparent failure on the part of IUC to design for and prevent adverse eflects of static or dynamic loading suggests that significant defects could exist in the PVC liners; thereby allowing wastewater to be released to the environment. Table 4. Summary of IUC PVC Liner Seam Test Data Tailings Cell No. of Tests Average Tear Strength tr)Reference (2) Fi e I d Manufac tur e d Se ams Cell 1 110 92.8%A Cell2 165 87.3%B Cell3 28 93.3%C Factory Manufacture d Se ams Cell 1 25 8t.5%A Cell2 90 82.4%B Cell3 l3 89.5%C Footnotes: l. Average seam tear strength relative to tear strength of the virgin PVC panel material.2. Sources of IUC PVC liner seam test data are as follows:A. 2|82DCE As-Built Report, Appendix D, BF Goodrich Company laboratory Reports of February 4, l98l (factory seams) and September 17, l98l (field seams).B. 2/82DCE As-Built Report, Appendix C, BF Goodrich Company laboratory reports of February 19, April 30, and May 30, 1980 (factory seams), and May 19, June 4, and June 16, 1980 (field seams). C. 3/83 EFN As-Built Report, Appendix B, September 20, 1982 Watersaver Company Inc Report (field seams), and September 3,1982 Dyanmit Nobel-Harte laboratory results (factory seams). Chemical Resistance of Adhesive - the above cited design reports cite the use of an adhesive to join the PVC liner panels in cells 1,2, and 3. As such, this adhesive forms a new component in the liner system. Unfortunately, no information was provided in any of the IUC design or as-built reports about the long-term resistance of the PVC adhesive used to contain contaminants found in the IUC tailings ponds, e.g., acidic solutions, diesel fuel, chlorinated solvents, etc. If the adhesive were to be more prone to chemical attack, the seams would become major points ofweakness in the FML system; thereby resulting in a discharge of wastewater to the subgrade environment. Memorandum Jwrc 27,2000 Page 18 5. C. Seam Cleaning Method Implications - the above referenced design reports simply state that the "... field seams shall be made only on lining surfaces that are cleaned of dirt, dust, moisture, or other foreign matter." However, no explanation was provided on howthis cleaning would be accomplished. If simple mechanical means were used to brush the dirt from the FML, dust and dirt could have easily contaminated the seam areas, easily resulting in weakened PVC seams. Better seams could have been constructed if solvents were used to clean the seam areas before application of the adhesive. However, poor or irregular application of cleaning solvents could also render seam weaknesses. Also, spillage of the cleaning solvent elsewhere on the PVC panels could also form other points of weakness in the FML system. Static or dynamic loading could later open these weak areas into FML perforations during the construction process. D. FML Wrinkles and Seam IntegritL- none of the above referenced design or as-built reports included measures used to eliminate wrinkles in the PVC panels before the seams were constructed. Ifliner wrinkles were to become incorporated inside a seam area, bypass conduits could be formed thru the seams that would allow wastewater to be discharged from the tailings cells. If no measures were provided in the engineering design, specifications, or as-built reports to prevent wrinkles from forming in or near seams, it is reasonable to expect that some PVC liner leakage may exist as a result of this oversight. Disrepair of Cell4,{: Need for Retrofit Construction - during an inspection of May, 1999, DRC staff discovered that the FML liner in IUC Tailings Cell 4,{ was in gross disrepair. During this inspection it was observed that at least a portion of one FML panel had separated from the liner and been blown out of the cell by the prevailing winds; thereby leaving the underlying bedding layer exposed to the elements (personal communication, Rob Herbert, DRC). At the same time it was observed that other seam areas of the FML in Cell4A had been nailed down with steel nails and 2-by-4 inch boards to prevent them from also blowing away (ibid.). During this inspection a green liquid was also observed to be contained in the bottom of Cell 4,{ (ibid.). During other inspections, IUC staff have explained that this liquid is a vanadium raffinate stored in Cell4A. As a result ofthese observations, DRC staffhave concluded that the Cell 4A liner system has been grossly neglected and damaged, and must be repaired before placing the cell in to service. Based on this neglect and the LDS design shortcomings mentioned above, DRC staff recommend that the existing FML in Cell 4A be removed and the tailings cell re-design and re-constructed to provide adequate LDS performance. Because IUC staffhave indicated that vanadium raffinate has been stored onthe Cell4,A. liner, decontamination ofthe existing FML bedding layer and foundation may also be in order during cell retrofit construction. As a result of these considerations, DRC staff recommend that Cell 4A not be authorized or included in any Permit; but instead that IUC be required to submit and complete a retrofit construction plan for this cell before its re-use for tailings or wastewater disposal at the facility. Memorandum Jvne 27,2000 Page 19 General Facility Design Concems / Issues 1. Mill Facilitv Area Sedimentation Pond: Potential Groundwater Pollution Source - the June, 1979 DCE design report shows that a sedimentation pond was constructed adjacent to the southeast corner of Cell 1 to receive stormwater drainage from the miIl site area and the ore storage piles (ibid., Sheet 4 and p. 6-3). This sedimentation pond was designed with an l1 acre-foot storage capacity, and without an outlet or overflow spillway. More importantly, the pond was designed without any liner. Consequently, water may only exit the pond thru either evaporation or seepage. Unfortunately, no "as-built" information has been provided by IUC regarding the Mill Facility Sedimentation (MFS) Pond. Consequently, DRC staff assumed that its construction conformed to the design provided in the June, 1979 DCE Report. During a site visit on May 9,2000, DRC staff inspected the MFS Pond site and found no open surface impoundment at this location. After inquiry,IUC staff explained that: 1) the MFS Pond had been filled with fly-ash waste in about 1990,2) the company now referred to this pond as the Fly-Ash Pond, and 3) soon after filling the pond with fly-ash the area near the Fly-Ash Pond had been re-graded to direct stormwater runoff from the mill site to Tailings Cell2. During the May 9 site visit it was apparent that a soil cover had been placed over the fly-ash (5/11/00 DRC memorandum, pp. 5 and 6). Based on the available information, it appears that both contact and non-contact stormwater runoff from the mill facility was at one time collected in the MFS Pond and ultimately discharged to groundwater. As a result, mill site area spills of reagents, chemicals, or wastewaters could have been retained by this sedimentation pond and also discharged to local groundwater. From on-site inspection and disclosure by IUC staff it is also apparent that the MFS Pond has also been used by the company for the disposal of fly-ash. As a result, the MFS Pond should be considered as a potential source of groundwater contamination at the facility. Source term investigations should be used to confirm or ascertain the presence of contaminants in this pond, and should be included in the ongoing groundwater contaminant investigation report. If contamination is confirmed, IUC should be required to make certain improvements in engineering design to mitigate or prevent any continuing groundwater pollution from this potential pollution source. Appropriate measures would include, but are not limited to: l) installation of an engineered cover system to minimize infiltration and point-of-compliance monitoring wells to determine any adverse impact to groundwater quality, or 2) removal ofthe fly-ash material and other contaminants, followed by appropriated disposal at another approved and engineered facility. Operational Issues / Concerns 1. Water Balance Monitoring - the June, 1979 DCE Report lists an aggressive program for water balance monitoring at the White Mesa facility, including: a local precipitation gauge, Memorandum Jvne27,2000 Page20 evaporation pan, staff gauges, and flow meters (ibid., p. 4-5). Inspections should be done to confirm these devices were installed, that historic measurements were made, and records kept. If such water balance monitoring data arc available, review and evaluation of the historic data should be done to determine if it can be an effective tool to measure performance of the discharge minimization technology approved under the Permit. 2. Annual Site Precipitation Rate - the June, 1979 DCE Report cites the average precipitation as 1 1.8 inches/year. This value is low. More recent information from the Westem Regional Climate Center indicates average annual precipitation is 13.38 inches (see Attachment 4, below). Discharge Minimization Technology (DMT) Considerations 1. Need for DMT Determination: Ground Water Ouality Protection Rules - in order for the Executive Secretary to issue a Permit for an existing facility, one that pre-dated the GWQP Rules, the following determination must be made first (UAC R-317-6-6.4.C.1 thru 4): " l. the applicant demonstrates that the applicable class TDS limits, ground water quality standards and protection levels will be met;2. the monitoring plan, sampling and reporting requirements are adequate to determine compliance with applicable requirements ;3. the applicant utilizes treatment and discharge minimization technologt commensurote withplant process design capability and similor or equivalent to that utilized by facilities that produce similar products or services with similar production process technologt, and 4. there is no current or anticipated impairment ofpresent andfuture beneficial uses of the ground water" Factors to be considered in arriving at the above listed determinations required of the Executive Secretary are listed in the discussion below. 2. DMT Performance Standard for Existing Facilities - discussions with Utah Division of Water Quality (DWQ) staff have confirmed that the maximum seepage discharge allowed from DWQ permitted existing facilities is 200 gallacrelday. As a result of this precedence, this 200 gallacrelday seepage discharge rate should be used as a Dishcarge Minimization Technology (DMT) performance standard for other existing facilities (personal communication, Larry Mize, DWQ. Under this performance criteria, undetected FML leakage from an existing disposal facility should be no greater than 200 gallacrelday. This criteria is amply reasonable, in that currently available FML technology allows leak detection system sensitivity as low as I gaUacrelday (US Environmental Protection Agency [EPA], pp. 8 and 30). This DWQ undetected discharge criteria is also applicable to both the operational phase and closed-cell condition ofthe facility (personal communication, Dennis Frederick, DWQ). Memorandum |wrc27,2000 Page2l 3. Unacceptable IUC LDS Design and Construction - based on available LDS design and construction information, undetected leakage from IUC Cells 2, 3, and 4,{ could range from about 2,500 to 840,000 gallacrelday, with an average of200,000 gal/acrelday (see discussion above). This possible undetected seepage discharge rate is much greater than the 200 gallacrelday DWQ criteria cited above. Admittedly, this estimate of LDS sensitivity is based on the permeability of the underlying bedrock and the system's resulting failure to force FML leakage horizontally to the leak detection pipeage. Actual seepage discharge thru the FML may be lower, depending on many contributing factors such as: thickness and permeability of the tailings, total effective head on the FML, number and size of defects in the FML, etc. However, it is clear that the existing IUC leak detection systems in question are ineffective at measuring leakage in light of the DWQ performance criteria for existing facilities (200 gallacrelday). Furthermore, the apparent lack of any LDS under Cell I is also unacceptable. As a result, DRC staff conclude that none ofthe existing disposal cells at the IUC facility has an adequate LDS. Nor can any of the existing LDS be used a satisfactory point of compliance for purposes of a Permit 4. Lack of Abilitv to Objectively Model IUC Cell Seepage - the above DRC leak detection sensitivity seepage rate estimates are worse-case figures. Prediction of actual or more realistic seepage discharge from the existing IUC tailings cell would require infiltration modeling studies. One common model used for such infiltration predictions is the EPA Hydrologic Evaluation of Landfrll Performance (HELP) model. Because each cell has a separate different design or is in a different stage of its life cycle, separate model simulations would be needed for each disposal cell. For example, Cell 1 is currently used for wastewater storage and has little sediment disposed there. Cell2 is near the end of its operational life and is being drained and prepared for final cover. Cell 3 is still only partially filled; while Cell 4 awaits retrofit and repair work before it can be used for disposal. Any infrltration model used will require determination of a number of engineering design, soil hydraulic properties, and weather variables. While many of these are known or can be deduced from available information, some inputs would be difficult to ascertain, and therefore, would possibly render the model results subjective and open to interpretation. Two (2) important, yet subjective input variables needed in the HELP model are: l) the number of field defects per acre in the FML, including those created during FML installation (seam defects, punctures, etc.), or develop thereafter in response to loading stress or chemical interactions, and 2) type of FML placement quality or degree of intimate contact between the FML and the over and underlying soil materials. Because the IUC disposal cells were constructed over 20 years ago, few people are available to provide input on the number of FML field defects that might have occurred during Memorandum June27,2000 Page22 installation. Furthermore, few or no records are available to confirm such, or provide information on the degree of FML placement quality. In addition, little can be quantified regarding cunent physical integrity of the FML, particularly with regards to chemical resistance of either the PVC membrane panels or the glues used to seam them. As a result, any zrsumptions made by IUC or DRC staff regarding these HELP model inputs would be subjective and open to dispute and argument. Certainly, based on the company's past resistance to State regulation, one can expect that any infiltration modeling used to further quantifu actual or probable seepage discharge from the IUC disposal cells will be long, argumentative, arduous, and defrnitely subj ective. 5. DRC Staff Recommendations - as a result of the above considerations and findings, DRC staff recommend that the agency forgo infiltration modeling as a means to determine compliance with the DWQ 200 gaUacrelday seepage discharge criteria for the operational phase of the IUC facility. Instead, DRC staff recommend that the following actions be completed: A. Necessary Operational Phase Improvements - distinct improvements should be made to groundwater monitoring dwing the facility's operational life, including, but not limited to: Additional Monitoring Wells - to allow each disposal cell to be individually monitored with a series of wells located immediately up and downgradient. These wells would be installed on the intemal dikes located between each cell. Additional Head Monitoring and Reporting - including frequent measurement of shallow aquifer water levels in all monitoring wells at the facility, careful characterization and monitoring of the apparent groundwater mound at the facility, and preparation of water table contour maps. Additional Groundwater Monitoring Parameters - including the addition of new groundwater monitoring analytes to better detect and quanti& any seepage discharge that may have been released from the IUC facility. Accelerated Closure and Compliance Schedule for Cell2 - IUC is currently in the process of stabilizing and advancing temporary soil cover over cell 2. consequently, DRC staff recommend a compliance schedule be included in the Permit that accelerates and makes enforceable closure ofthis tailings cell in a timely manner. Retrofit Construction of Cell 4,{ - because Cell 4A has not yet been used for tailing disposal, and is in a state of disrepair, it is feasible to re-design and re- construct this cell to meet current Best Available Technology requirements under the GWQP Rules. Consequently, DRC staff recommend that the 1) 2) 3) 4) s) Memorandum Jlur:re27,2000 Page23 B. Permit require Cell 4,{ to be upgraded to meet current BAT design and technology standards before being placed into service. Possible Operational Improvements - several improvements could be made to disposal cell operations to minimize seepage discharges from the IUC facility, including: l) Disposal Cell Head Minimization - in the event that the IUC disposal cells were to be operated on a continuing basis, and for an extended period of time, certain improvements to head minimiz,ationcould yield significant decrease in seepage flux from the facility. This seepage driving head could be minimized at IUC by: a) Installation of a clay internal liner slurried over the top of the existing tailings surface; thereby reducing vertical seepage to the underlying FML, and b) Installation and full-time operation of pumps to remove fluids from the existing leachate collection (slimes drainage) system constructed immediately above the FML. This may require installation of automation and backup equipment to ensure full-time operation. c) careful measures to minimize the depth of fluids on top of the tailings, or on top of the FML in wastewater Cell l. Timely efforts to pump and remove these fluids and re-circulate them back to the mill will also help minimize driving head conditions in the cells. However, if the IUC facility were to be closed soon after issuance of the Permit, these head minimization efforts would do little to reverse any seepage effects caused by 20 years of historic operation. 2) FML Lining for Mill site Stormwater / Sedimentation Pond - an FML liner and leak detection system could be installed for the sedimentation pond found East of Cell I that is used for disposal of stormwater runoff from the mill site and contact stormwater runoff from the ore storage pile. 3) contaminated Groundwater Recovery System - in the event that contaminated groundwater is found atthe facility, IUC should install a series of pumping wells to recover and contain said water. Closed-Cell Design Improvements - review of the proposed IUC tailings cells cover design in the September, 1996 Titan Environmental Report, shows that it includes four (a) layers above the waste form, as summarized in Table 5, below (in descending order): C. Memorandum Jrne27,2000 Page24 able 5. Summar of September,1996IUC Tailings Cover S Sideslope Areas Topslope Areas Description Thickness (inch)Description Thickness (inch) Riprap 3.0 Riprap 12.0 Random Fill 24.0 Random Fill 24.0 Radon Barrier t2.0 Radon Barrier 12.0 Random Fill 36.0 -Random Fill 36.0' Design Footnote: r*Thickness varies in order to make final grade for cover. Several improvements could be made to the cturent cover system designto minimize discharge of the facility to groundwater, including, but not limited to: 1) Inclusion of a Filter Drainage Layer Above Radon Barrier - the cover design proposed does not include a filter drainage layer above the radon barrier. Rather, it calls for a 2-foot thick "upper random fill" layer, which is reportedly made of a clay-like material(9l96Titan Report, p. 5 and Appendix D, HELP model output file "efrr-fin2.out", Layer 1, permeability: 8.8E-7 cm/sec). If all or part of this layer were designed and constructed with a higher permeability, infiltration that may accumulate on top ofthe clay radon barrier could be diverted out ofthe cover system and prevented from entering the waste in the disposal cells. 2) Reduction ofRadonBarrierPermeabilitv - the currentcover design simulated by IUC with the EPA HELP model assumed a radon barrier permeability of 3.7E-8 cm/sec (9196 Titan Report, Appendix D, HELP model output file "efrr-fin2.out", Layer 2). This permeability could feasiblely be reduced to l.0E-8 cm/sec. Addition of FML/clay composite Layer - the radon barrier could be converted to a FML I clay composite by addition of a FML immediately above the clay radon barrier. This design change would dramatically reduce the seepage rate thru the tailings waste. Provide Shorter Drainage Path Lengths - in the current IUC cover system design, the "clay-like" random filI layer extends uniformly from the North side of cell 1 to the South side of cell 4A, adistance of over 3,300 feet(9196 Titan Report, Figure 1, East side of cells2,3,and 4A). This provides for a very long path length for seepage to travel horizontally in the riprap layer before it can exit the system. As a result, seepage losses are maximized during the course ofthis travel path; thereby maximizing infiltration thru the 3) 4) Memorandum June 27,2000 Page25 tailings waste. Redesign of the cover system could allow for shorter horizontal drainage paths; thereby allowing the seepage to exit the system sooner; minimizing seepage thru the underlying waste. 6. Compliance with Required Determinations - determinations required by the GWQP Rules regarding existing facilities (UAC R3l7-6-6.4.C) can be accomplished as follows: C. Groundwater Class Limits. Standards and Protection Limits - after completion of site characteization and resolution of the DRC February 7,2000 request for additional hydrogeological information, the Executive Secretary should be able to confirm groundwater class of the shallow aquifer. After installation of the additional groundwater monitoring wells needed at the facility, the Executive Secretary should also be able to determine if IUC currently meets State Ground Water Quality Standards and Protection Levels in the shallow aquifer around each disposal cell. Monitoring Plan. Sampling and Reporting - improvements will be made to groundwater monitoring at the facility to better charactenze local conditions and better detect tailings contaminants in the shallow aquifer (see discussion above). Improvements can also be incorporated for better quality assurance / quality control and reporting for future construction projects at the facility. Thus, these requirements in the GWQP Rules should also be met. Discharge Minimization Technology - it is clear that the current engineering containment at IUC is not equivalent to what similar uranium mill operators use today. This discrepancy is largely because the White Mesa facility was constructed 20 years ago. Since that time, great improvements have been made in FML materials, design, and construction techniques, that make the IUC facility now appear outdated and obsolete. One example of this disparity is the Plateau Resources uranium mill tailings facility near Ticaboo, Utah. There, double FML liners, full coverage leachate removal systems over the upper FML, and full coverage LDS between the FMLs were designed with multiple observation sumps to minimize driving head, provide rapid reporting, and effect high FML leakage recovery. However, certain improvements can be made at White Mesa including: l) point of compliance monitoring wells for each individual cell, 2) head minimization equipment and operation for Cells I and 3, 3) accelerated closure of Cell 2, 4) re- design and retrofit construction for Cell 4 before retum to service, and 5) improved cover system design for all4 Cells at the facility. Absence of Current or Anticipated Impairment of Beneficial Use - this requirement can be considered satisfied at IUC if: l) groundwater is adequately and carefully monitored at the facility, and 2) the current IUC design and construction has not caused any adverse impact on local groundwater quality. Additional site A. B. D. Memorandum Jlurlle27,2000 Page26 characterization and improvements in the existing groundwater monitoring network can establish if compliance has been met in these areas. However, in the event that groundwater pollution is discovered and confirmed at the facility, the Executive Secretary would be hard-pressed to make this last affrrmation required by the GWQP Rules. In that event, beneficial use of local groundwater could still be protected thru other means, such as implementation of a groundwater recovery or remediation system to protect downstream groundwater users. For this reason, it will be critical to coordinate the Permitting efforts for this facility with ongoing contaminant investigation studies at the IUC facility (see 8123199 DRC NOV and Groundwater Corrective Action Order). Predictions of future degradation of groundwater quality at the facility would be difficult to provide, based on a lack of supporting information, and would be highly subjective, as discussed above. Conclusions After review of the engineering design, specifications, and as-built reports provided by IUC, DRC staff have concluded that: It is unlikely that any leak detection system exists under IUC wastewater disposal Cell l. Therefore, point of compliance groundwater monitoring wells will be required around Cell 1 in the Permit. Leak detection systems found under IUC Cells 2 and 3 are grossly inadequate. Based on available system design, geometry, and underlying bedrock permeability, DRC staff estimate that FML leakage would remain undetected by the current system until leakage flows reach a rate of between 2,500 and 840,000 gallacrelday, with an average of about 200,000 gaVacrelday. This lack of leak detection sensitivity fails to meet DWQ performance standards for existing facilities (200 gaVacrelday). As a result, the existing design fails to comply with the DWQ Discharge Minimization Technology (DMT) requirements found in the GWQP Rules. Multiple lines of evidence also suggest that the 30-mil PVC membrane used as FML in Cells 1,2, arrd,3 is prone to excess leakage due to a number of factors, including: 1) suspect preparation of FML bedding and protective blanket layers, 2) lower PVC puncture strength, 3) higher PVC water vapor transmission, 4) long-term degradation of PVC membranes due to leaching ofplasticizer compounds and organic chemical attack, and 5) suspect PVC seam preparation and construction methods. As aresult of leak detection system design shortcomings and suspectphysical condition and integrity of the PVC FML in Cells 1,2 and 3, a demonstration of adequate DMT will largely focus on performance of the final cover system, and to a lesser degree on operational 1. 2. 3. 4. Memorandum Jwrc27,2000 Page27 5. 6. 7. 8. improvements. Operational improvements, include, but are not limited to: l) additional groundwater characteization and installation of new monitoring wells for each individual disposal cell,2) additional water quality monitoring parameters, 3) accelerated closure for Cell2, and 4) head minimization efforts for Cells 2 and3. Improvements to the final cover include: deueased radon barrier permeability, addition of a high permeability filter zone and a FML/clay composite layer in the cover design, and shorter drainage path lengths. Although the leak detection system design under Cell 4A represents an improvement over previous disposal cells at the facility, its leak detection shortcomings, and current state of neglect and disrepair mandate that this cell be retrofit to meet current Best Available Technology (BAT) standards before any use for tailings or wastewater disposal activities. Lack of separate and independent construction supervision and construction quality control/quality assurance (CQA/QC) may have contributed to an increased rate of construction defects in IUC Tailings Cells l, 2,3,and4. Revisions need to be made to any futureIUC CQA/QC efforts andplansto ensuremodemconstructiontechniquesandprovide confidence in the engineering containment of new wastewater and tailings disposal cell construction. An engineering survey error of approximately 900 feet has been discovered at tailings Cell 2, which must be resolved. Resolution of this error can be combined with surveys needed to correct other errors for the groundwater compliance monitoring wells. An unlined sedimentation pond formerly drained the IUC mill site and ore storage pad area and has been used for on-site disposal of fly-ash. This Fly-Ash Pond is a potential source of grourdwater pollution that needs to be investigated. Historical and ongoing operation of this Fly-Ash Pond constitutes a potential groundwater contamination source at the IUC facility. Appropriate measures to control groundwater pollution at this facility include, but are not limited to: 1) installation of an engineered cover system followed by point-of- compliance monitoring wells, or 2) removal of the fly-ash material and other contaminants and appropriated disposal at another approved and engineered facility. Compliance with the GWQP Rules for issuance of a Permit to an existing facility at IUC can be achieved as described above. However, if groundwater contamination is discovered near Cells 1, 2, or 3 during additional site characteization or installation of new groundwater monitoring wells, the Executive Secretary will not be able to affirm the lack of impairment of present and beneficial use without additional groundwater remediation measures. 9. Memorandum Jwrc27,2000 Page28 References D'Appolonia Consulting Engineers, Inc., June, 1979, "Engineers Report Tailings Management System", unpublished consultants report, approximately 50 pp.,z figures,2 appendices. D'Appolonia Consulting Engineers, Inc., May, 1981, "Engineer's Report Second Phase Design - Cell3 TailingsManagement System", unpublishedconsultants report, approximately2}pp., I figure,3 appendices. D'Appolonia Consulting Engineers, Inc., February, 1982, "Construction Report Initial Phase - Tailings Management System", unpublished consultants report, approximately 7 pp,6 tables, l3 figures,4 appendices. Energy Fuels Nuclear, Inc., March, 1983, "Construction Report Second Phase Tailings Management System", unpublished company report, 18 pp., 3 tables, 4 figures, 5 appendices. International Uranium Corporation, May, 1999, "Groundwater Information Report White Mesa Uranium Mill Blanding, Utah", unpublished company report, approximately I 19 pp., 12 tables, 15 figures, and 8 attachments. International Uranium Corporation, January 28,2000, "Transmittal of Program for Delineation of Elevated Chloroform in Perched Groundwater at MW-4, for Chloroform Investigation Phase 4 - UtahDEQNoticeofViolationand GroundwaterCorrectiveActionOrder, UDEQ Docket No. UGQ (sic)-20-01, Issued on August 23,1999",unpublished company transmittal letter from David C. Frydenlund to Don A. Ostler, P.E.; includes a January 28,2000 technical report by Stewart Smith, Roman Z. Pyrih, and Roman S. Popielak, "Program for Delineation of Elevated Chloroform in Perched Groundwater at MW-4", unpublished consultants report, 17 pp.,2 figures, 1 table, I appendix. Koemer, R.M. 1990, Designing with Geosynthetics,2dEd.,Prentice Hall, Englewood Cliffs, New Jersey,652pp. Moulton, L.K., August, 1980, "Highway Subdrainage Design", U.S. Department of Transportation, Federal Highway Administration PublicationNo. FHWA-Ts-80-224,(reprinted July, 1990), 162pp. Titan Environmental Corporation, July, 1994, "Hydrogeologic Evaluation of White Mesa Uranium Mill", unpublished consultants report, approximately 51 pp., 5 tables, 19 figures, 7 appendices. Titan Environmental Corporation, September,1996, "Tailings Cover Design White Mesa Mill", unpublished consultants report, l0 pp.,4 figures, 8 appendices, and references. Memorandum |wrc27,2000 Page29 U.S. Environmental ProtectionAgency, Augus! 1989, "Requirements forHazardous Waste Landfill Design, Construction, and Closure", Technology Transfer SeminarPublication, EPN62514- 891022,127 pp. Umetco Minerals Corporation, April 10, 1989, "Cell 4 Design", unpublished company report, includes: l) April 10, 1989 letter from Curtis O. Sealy to Edward F. Hawkins, 1 pp., with 60 pp. oftechnical response materials, and 2) August, 1988 Umetco Minerals Corporation "Cell 4 Design Tailings Management System", unpublished company report, 17 pp.,2 attachments, and2 appendices. Utah Division of Radiation Control, August 23, 1999, "White Mesa Uranium Mill: Notice of Violation and Groundwater Corrective Action Order, DocketNo. UGW20-01", unpublished agency compliance action, 3 pp. Utah Division of Radiation Control, February 7,2000, "Muy, 1999IUC Groundwater Information Report: DRC Request for Additional Information Related to Site Hydrogeology", agency request for information, 18 pp.,2 attachments. Utah Division ofRadiation Control, May I 1, 2000, "International Uranium Corporation White MesaMill; DRC Site Visit of May 9, 2000 Staff Conclusions and Recommendations", unpublished agency memorandum, 9 pp., 20 photographs. LBM:lm attachments (5) cc: Larry Mize, DWQ F :\...\iuctailseng.wpd File: IUC Groundwater Permit P1b Utah Division of Radiation Control Summary of Available Permeability Information for the IUC White Mesa Uranium Mill Tailings Facility DRC Spreadsheet HydCond.XLS Tabsheet alldata an oa.eo o a4 o()o5 o.t(! 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NNNc{NN Erf*#*i:i'riLo-atoiAPEPpEciliEilEilO)OO)(J(,)():ll --t Pll .t Nll n-Sr-> r E r ) r E - >' (\l E-E - 6 -E r b -E r b EE EE EE EE EE 8E EEEEEEoooooooooooo oc,a\.E OLriOrotloo;,(O 'i'_coaEEa[LlrrarNo:3t'=(f)a^c{ EE(UeElco=EO*EoL$ -$L NE\o.=EELot*<b ilocLO =6Eorr,c)E(oOr.()(f,0NE(Od>+(olc(f)*E *-CC ooc.SNtr#ro ii(-f I@dS -: EaNoLa*$cf)lr)rV o-c*.!oNN.Es-k**oaoa€aottEO)OOrrO"tA$ll @>l'-E-l-E Co b rE :i:i -jj -ij6E EE 6EtrEEEEEoooooo Utah Division of Radiation Control Summary of Estimated Static Loads on Flexible Membrane Liners at IUC White Mesa Uranium Mill Tailings Cells Nos. I thru 4 DRC Spreadsheet CellEng.XLS Tabsheet Staticload CellEng.xls - Staticload design data from A82 D'Appolonia Sheef I of 16 dry density from 2/82 D'Appolonia Design Report (Ceils 1 & 2), p. 2-2 4120t2000 1 nla 2 3 4 5,614 5,608 5,593 5,583 5,573 5,556 5,583 5,573 5,556 80 80 80 31 35 37 31 35 37 92 92 92 2,852 3,220 3,404 2,480 2,800 2,960 0.44 851 3,7030.44 961 4,181 0.44 1,016 4,420 0.44 851 3,3310.44 961 3,761 0.44 1,016 3,976 dry density from 5/81 D'Appolonia Engineering Design Report (Ceil 3), p. 1-2 1 nla 2 5,614 3 5,608 4 5,593 IUC Tailings Cells: Static Load on FML Tailings Elevations Tailings Height (ft) Utah Division of Radiation Control Plot of IUC Tailings Cells 2 and 3 Under drain Filter Gradation and Comparison with IUC Reported FML Bedding Layer Gradation Modified from 2182 D' Appolonia Consulting Engineers Report Figwe 13. +Fa,co@ ICDF =E,OG,zu ;d)i2. l I CLEAR OPEN 3' tl., SIEVE ,,ara lr.r.NGS I HYDnOnaEten ANALyStSt I )'* Ln)u'*"-6 l)*,o src-, . 3;,o, ].a l<z-Pf=4,,0b.&1 i-\ ct^P-f'<o o F Ig ttJ3 o o UJz F UJE Fz IJJ OE " IJJ o- 20 30 F !I UJ = @ E IJJz lr Fz IJJOE IJJo. ' l'o ' E' i '^ o.,nq rF. o'ol PARTIc(H' oTaMETER tN iru roo 0.0001 OBBLES GRAVEL SANO SILT ANO CLAY FRACTIONco.rr I lim mrdium I tinr SATPLE DEPTH SOIL OESCRIPTION u.s.c.s.L. L.P. L,w.a-o-SAND. SOUE GRAVEL SP o.25 t5 kola#D*/-2 ---4e1 l,l l F-,Cv- 7c ({ro,^ lr\.5 ,Do( " A;t^,,-,1 fuLJ*'q; D"rt,,- ,-T,nL1 llf Dt B \ qt P*". f N'']eo f,<ta ,\ 0,0 -- o,? a r nr z) \1 p^^r;Q -* r/'l,s ?B ,{-u,a: - lol -/ o tr'?1" *rJ;7 r do)i;t''o t a ( p 1-\) FIGURE 13 GRAIN SIZE ANALYSIS BEDDING MATERIAL ? . PREPARED FOR ENERGY FUELS NUCLEAR, INC. DENVER, COLORADOlbt+,-rt ( qod n):\x"x?.()r-,()NL \ Dr,r;- DtA 1J, eS /--r,.*J rrT ^*a ,{rr.--- 14 -5 Df 5-bJ*,>---22 D.i-^ti , G,rA .ra a. ) /'L p"" V //a @o 9s-<v< ) b/o =- /1/a, /t-o f t{*<- (O, t+a ^,1 z) \rl b*,'I, = I 11 ,h f eK s/sz Etril cet)i {fv tr*L+ t i. z -r) Climate Summary Data for Blanding, Utatr from the Westem Regional Climate Center Intemet Webpage Address : http ://www.wrcc.dri.edu/cgi-bin/cliRECtM.plfutblan hqp://www.wrcc.dri.edu/cgi-bin/cliRECtM.pl?utblnnoo May Jun Jul 7r.9 83.0 88.3 41.7 50.4 57.6 0.73 0.47 l.l9 0.2 0.0 0.0 000 Aug Sep Oct 86.0 78.r 65.9 55.9 48.0 37.7 1.40 r.26 1.46 0.0 0.0 0.3 000 BLANDING, UTAH (42073 S) Period of Record Monthly Climate Summary Period of Record : l2l8ll904 to l2l3lll999 Jan Feb Mar Apr Average Max. remf&ature (ry 38'7 44'7 sz's 6l'9 Average Min. femp&ature 1f1 16'6 22'0 27 '5 34'0 Average Total PrecipTtatio" (in.l 1'37 1'18 1'01 0'88 Average Total SnowF'all (in.) ll'2 7 '5 4'3 2'0 Average SnowDepth"(in.)4300 Percent ofpossible observations for period ofrecord. {ax..}mq.,99"/: Min. Temp.:96.5o/oPrecipit_ation:96.8%o Snowfall: 91.7%SnowDepth: 69.5% Check Station Metadata or Metadata graphiCs for more detail about data completeness. Nov Dec Annual 51.3 41.0 63.6 26.4 18.9 36.4 1.05 1.37 13.38 3.4 10.3 39.3 011 Western Regional Climate Center, wrcc@dri.edu lof I 3/29/2000 9:04 AM Utah Division of Radiation Control Estimate of IUC CelI4A Leak Detection System Efficiency DRC Spreadsheet CellEng.XLS Tabsheet Cell4aLDS cel!4A Leak Detectigtr tygle! tgysEqe tI_ A4AA Umetco nepofWestern e*ngineers Drawing Sheerc44 1,000 1,250,000 1,575.0 Total:l 20,230.0 Ratio of Leak Detection Cover 2 3 4 5 6 7 CellEng.xls - Cell4aLDS 4t28t2000 Page 1 CellEng.xls - Cell4aLDS 4128t2000 Gel!: C6 Comment: Approximate Drain Arm Length: from 8/88 Umetco Report, Western Engineers Design Drawing Sheet c44. Cell: DG Comment: Cell44 Leak Detection System Pipeage Diameter of lnfluence: cross-section plans provided by IUC show that each LDS pipe was to be installed inside an 18 inch wide trench, lined with an FML (40 mil HDPE or 30 mil PVC). Engineering plan shows FML to extend a distance of 1 foot to either side of the pipe's trench. Consequently, total width across which leaks could be directed to the LDS collection pipe = 3.5 feet. Page 2 StateDf Utah t YDEPARTMENT OF ENVIRONMENTAL QUALIT DIVISION OF RADIATION CONTROL Michael O. LeavittGovemor Dianne R. Nielson. Ph.D. Executive Director William J. SinclairDirector TO: FROM: DATE: SUBJECT: MEMORANDUM Dane Finer *o"uW ,krl* LorenMorton b B./l*"L- May I l, 2000 International Uranium Corporation White Mesa Mill; DRC Site Visit of May 9, 2000: Staff Conclusions and Recommendations. Executive Summar.v Field observations combined with a continuing lack of engineering design or construction data reinforces the staff s previous conclusion that Cell t has no leak detection system. Field inspection also shows that improvements could be made to the Cell2 slimes drain recovery system to minimize head conditions on the FML by addition of a modern transducer or float switch to the pump controller equipment. Similar controllers and a pump system could also be added to the Cell 3 slimes drain recovery system and operated to minimizehead over the FML in that cell. Based on the cunent disrepair and neglect of the Cell 4A FML, lack of FML integrity indicated by historic LDS flows, inadequate FML design, small waste volumes currently stored there, and the apparent lack of adequate engineering containment for the vanadium salt residual left on the cell floor, DRC staff recommend that Cell44' be: 1) decommissioned by removal and disposal of the FML and vanadium salts left on the floor, and2) re-designed and re-constructed before use again for waste storage or disposal. Site inspection also found the existence of an un-lined Fly-Ash Pond at the facility. In order to minimize potential pollution of local groundwater resources, the upcoming Permit should require IUC to either close this facility with an adequate engineered cover system and compliance monitoring wells, ordecommissionthe Fly-Ash Pond afterremoval and approved disposal elsewhere of the offending waste material. A Process Wastewater Catch Pond was also discovered at the IUC facility that stores and disposes of floor drainage from the mill and solvent extraction building at the site. Close review of the engineering design and construction will also be needed for this facility in order to determine adequate DMT. However, this review can be incorporated into review of the Spill Management Plan, scheduled to be submitted in November, 2000. Other spill containment related facilities can also be reviewed at that time, including acid and product storage tanks at the mill site. Memorandum May 11,2000 Page2 Four unlined Wildlife Ponds were also found along the eastern margin ofthe IUC facility, that may pose a source of man-made recharge to the uppermost aquifer. Operation of these ponds may have already dramatically changed local groundwater flow directions, by forcing local groundwater to flow in a westerly direction. This possibility must be carefully investigated before DRC approval of a compliance monitoring well network for the IUC facility. If it is found that these Wildlife Ponds have altered local groundwater conditions, then the DRC will be forced to: l) conclude that vadose zone residence time is short at the White Mesa site, and 2) require installation of new monitoring wells to adequately monitor the facility. Observations. Findings. and Recommendations The purpose of this memorandum is to document observations made during a site visit at the Intemational Uranium Corporation (IUC) White Mesa Uranium mill facility. I arrived on site with Ray Nelson at l:20 pm and met with Messrs. Ron Hochstein and Bill Deal of IUC. Observations made by DRC staff and recommendations resulting therefrom are as follows: 1. Tailings Cell I - during the inspection we drove around the perimeter dikes of Cell 1 and found that IUC had installed an electric mine fan near the center of the south dike to blow air over the water surface and enhance evaporation. We also inquired about the possibility of a leak detection system (LDS) under Cell 1 during the visit. In response, Mr. Deal said that he was not sure if a LDS had ever been built under Cell 1, and offered to examine engineering plans at the mill office. Later in the mill office Mr. Deal said that he could find no engineering plans for Cell 1. However, during the inspection, we observed an open ended 4-inch HDPE pipe protruding from the ground at roughly a 45o angle in the general vicinity of the mine fan on the Celt I south dike. Unfortunately, neither Messrs. Deal or Hochstein knew if it accessed a LDS. Furthermore, this if it were a LDS access pipe it is much nuurower than any other LDS access pipe found at the facility during the visit (see discussion below). Consequently, DRC staff continue in their conclusion that no LDS exists under Cell 1. 2. Tailing Cell 2 - as a part of the inspection we drove around the perimeter dikes to Tailings Cell2, where we found that an interim soil cover has been advanced over the vast majority of the cell; leaving the tailings exposed only across a small area around the cell's center access ramp. At this location, the tailings appeared dry. Upon inquiry, Mr. Hochstein explained that: 1) approximately 35,000 tons of tailings capacity remains in Cell 2, and,2) because the tailings in Cell 2had already reached the freeboard limit, the tailings waste placed in Cell 2 would have to be dry. As a result, company practice is to use the remaining Cell2 capacity for direct disposal of 1 1e.(2) waste from In-Situ Leach (ISL) operations; and reserve wet tailings slurry disposal for Cell 3. Memorandum May 11,2000 Page 3 During our Cell 2 visit we found that a small former spillway had once been cut into the south dike, located west of the center of the cell, where tailing effluent was allowed to spill over into Cell 3. No flexible membrane liner (FML) was apparent at this location. Consequently, tailings leachate could have easily been discharged to groundwater in the past during periods of Cell2 overflow. We also observed the access pipes to the LDS and slimes drain systems (SDS) at Cell 2. In contrast to Cell 3, the LDS and SDS access pipes at Cell 2 were constructed in a vertical configuration instead of inclined down the inside of the south dike, as at Cell 3 (see attached photographs). Upon later reflection, it was clear that a vertical configuration was necessary in that IUC had constructed a 120-foot access ramp from the south dike into CeIl2 (see 6179 D'Appolonia Engineers design report, Sheet 9). As a result the LDS and SDS access pipes had to be vertical in order to accommodate the geometry available. Both access pipes at Cell 2were made of HDPE material, about 18 to 20 inches in diameter. In the SDS system we observed a submersible Grundfos pump, dedicated power, and a pump controller had also been installed (see attached photographs). Upon examination, DRC staff found the controller to consist, in part, of a simple household appliance timer that cycled the pump on 6-times aday, for about 15 minutes each, for a daily total pump time of 90 minutes. At the time of the visit, the pump was on and discharging a clear fluid into Cell 3 via a 3 inch HDPE pipe at a rate of about 5-6 gallons per minute. IUC staff both confirmed that the SDS controller did not include any float switch or transducer to minimize head on the Cell2FML. After inquiry, Mr. Deal explained that IUC staff monitored the LDS access pipe for the presence of fluids by dropping a rope or cord down the pipe and removing it to detect any presence of fluids. During the inspection, DRC staff had no water level monitoring equipment available, and therefore could not sound the depth of any water therein. Nor did the staff have a mirror or a flashlight available to light the bottom of the access pipe for visual observation. Consequently, it is unknown if water was present in the Cell2LDS at the time of inspection. Upon inquiry, Mr. Deal said that no fluid had ever been detected in the Cell2 LDS. 3. Tailings Cell 3 - during the inspection we drove the perimeter dikes for Cell 3, where we found that interim soil cover had been advanced over the eastem l/3 of the cell. Along the western margin of Cell 3, IUC had set up a trash pump and at least 3 ""rainbird"" type sprinklers to re-circulate tailings effluent over the tailings "beach" front. IUC staff both explained that the goal of this wastewater sprinkling was to form a salt crust over the tailings and thereby prevent wind dispersion of the exposed Cell 3 tailings waste. During the visit, Mr. Hochstein confirmed that Cell 3 had remaining capacity for 900,000 tons of tailings. Memorandum May 11,2000 Page 4 At the center of the south dike we found the Cell 3 LDS and SDS access pipes. Both consisted of about 12 inch diameter black HDPE pipe, were inclined down the inside slope of the Cell 3 south dike. At the time ofthe inspection, no pumping equipment was apparent in either the LDS or SDS access pipes. Unfortunately, the Cell 3 LDS access pipe was cut so low that soil from the dike had washed down the access pipe (see attached photograph). The apparent soil washed down the pipe has the potential to plug the LDS and render it ineffective. A smaller diameter grey plastic pipe, approximately 314-inch in diameter, was also observed inside the Cell 3 LDS access pipe. Upon inquiry, Mr. Deal explained that the purpose ofthe grey pipe was for leak detection and that to detect the presence of fluids in the LDS, IUC staff would simply blow air down it and listen for any bubbling sound. During the inspection, DRC staff blew air into the nrurow pipe by mouth and found a back pressure or resistance existed in it, and that no bubbling sound was heard. Consequently, DRC staff removed the 3/4-inch pipe to inspect it for wetness. Upon removal, the narrow grey pipe was observed to be dry. DRC staffthen concluded that the resistance detected in the narrow grey pipe was likely due to sediment or some other type of internal plugging of the narrow pipe. During the inspection, Mr. Deal explained that fluids had been detected in the Cell 3 LDS access pipe in the past, but that studies conducted by IUC had indicated that the fluid was from disposal operations at the "fly-ash" pond near the mill site, and not Cell 3 (see discussion below). 4. Tailings Cell 4A - we drove the perimeter dike of Cell 4A, which is located south of Cell 3, along its eastern margin. Visual inspection found a white salt precipitate on the bottom of Cell 4A with small isolated pools of blue and bluish-green fluid. Mr. Deal explained that the salt cake was evaporated remains of vanadium raffinate put into Cell 4A by Umetco, a former owner of the mill. Observation also found that at least 5 areas existed on the Cell 4^A side slope area where the FMLpanelshadbeenblownoffandremovedbythewind. Betweenthese 5 areas, DRC staff estimated that about 20 - 25 % of the existing FML on the Cell 4A side slope areas had been rendered ineffective and void. There were also many other areas across the Cell 4A side slope area, where 2-by-6 inch lumber had been placed on the FML and steel spikes nailed thru it to secure the FML to the underlying soils, and thereby hopefully prevent the FML from being removed by the wind. DRC staff estimated that the FML had been punctured in this manner along several hundred feet of seam length in Cell 4A. DRC staJf also observed that a geotextile fabric had been installed immediately beneath the FML. Mr. Deal stated that undemeath this material, that IUC had placed clayey soils; presumably to encourage FML leakage to report to the LDS access pipe located at the Memorandum May I l, 2000 Page 5 southwest corner of Cell 4A. Unfortunately, this type of configuration, with geotextile sandwiched between the FML and the clay, allows wide spreading of FML leakage; thereby maximizing the volume of leachate released to the environment. During the inspection, we observed the LDS access pipe at the southwest corner of Cell 44. There, we found that IUC had installed a submersible pump and dedicated power to re- circulate LDS leachate back onto the main FML. Mr. Deal explained that fluid appeared in the LDS shortly after Cell4,A. was put into service, and that the NRC had required IUC to install the pump-back system. As a result of these findings, DRC staff recommend that a condition be added to the upcoming draft Ground Water Discharge Permit (Permit) to require Cell 44 be: l) decommissioned in a timely manner to eliminate seepage discharge of contaminated storm water and precipitation from the facility to local groundwater. Such decommissioning should include removal and ofthe vanadium salts and removal and disposal of the degraded FML, and 2) Cell 4,{ be re-designed and re-constructed to meet State Best Available Technology requirements, and approved by DEQ, before return to any use of the cell for waste storage or disposal. 5. Former Mill Site Sedimentation Pond (Fly-Ash Pond) - during the visit we inspected the former mill site sedimentation pond located east of the southeast corner of Cell l. The original engineering design drawings called for this l1-acre-foot un-lined disposal pond to receive storm water drainage from the mill site area(6179 D'Appolonia Engineering Report, p. 6-3 and Sheet 4). During the visit, Mr. Deal took us to where the pond was located; however, the it was not obvious because IUC had backfilled the pond and largely restored local grade. Mr. Deal explained that: 1) IUC had backfilled the former pond with fly-ash from the former coal-fired boilers used at the mill, 2) backfilling was complete about the time that IUC converted the boilers to propane in about 1990, and 3) historic fluids discovered in the Cell 3 LDS were attributed by IUC to wastewater leachates discharged form the unlined sedimentation pond. Later when use ofthe fly-ash pond was discontinued, Cell3 LDS fluids diminished (see discussion above). Based on these observations and findings, it is clear that the Fly-Ash Pond is a potential source of groundwater pollution at the facility. As such, the upcoming Permit should require IUC to either: 1) design and construct adequate cover system over this pond to minimize and prevent seepage discharge from the facility; including installation ofcompliance monitoring wells for it, or 2) decommission the Fly-Ash Pond by removal of the fly-ash material and disposal elsewhere at an approved facility. In order to beffer protect local groundwater resources, this closure or remediation should be completed in a timely manner. Memorandum May 11, 2000 Page 6 From our field inspection it was apparent that currently mill site drainage generally flows into Cell l, and not into the former sedimentation pond. 6. New Truck Decontamination Facility - during the inspection, I visited the new truck decontamination facility located in the northeast comer of the mill facility near the ore grizzly. There I found a concrete lined and bermed pad that gravity drains to a single wall steel wastewater holding tank. The tank was located immediately south of the truck decontamination pad, and had two chambers; one used for sedimentation. Mr. Deal explained that: l) water used at the decontamination pad was simply recycled from the wastewater holding tank, 2) sediments that accumulated behind the baffle are mucked out with a backhoe and placed back on the ore storage pad for future processing by the facility, and 3) disposal of wastewater from the holding tank would be done on a batch basis, by connection of a temporary hose and drainage or pumpage into the milling process system. During our visit, Mr. Hochstein explained how truck decontamination was done at the facility, as follows. First, intermodal shipments were dropped by the trucking company on the north side of the asphalt access road, outside of the restricted area. Second, an IUC tractor rig then leaves the restricted area to pull the intermodal trailer in. After dumping, the intermodal and trailer are hauled by the same IUC tractor to the new truck decontamination pad for wash-down. Then the intermodal is hauled to the south control gate radiologic survey. There, extra pebble-sized gravel has been added to improve drainage and provide a dry place for the truck to be surveyed. If needed, extra hand washing can be done while the intermodal is parked on the gravel. After the intermodal and its trailer pass the radiologic survey, the IUC tractor tows it outside the restricted area and parks the intermodal on the south side ofthe access road where it waits for the trucking company tractor to pick it up and haul it back to the rail spur at Cisco. 7 . Process Wastewater Catch Pond - during our inspection a process wastewater catch pond was found on the northwest corner of the mill site, located east of the northeast comer of Cell 1 and west of the mill's thickener tanks. It appeared to be about 1-acre in size and lined with a black FML. Mr. Deal stated that this catch pond received floor drainage from mill and solvent extraction circuit buildings. If this is true, this pond could also be a source of potential groundwater contamination at the facility. Consequently, additional DRC review will need to be completed regarding the engineering design and construction of this catch pond in order to ascertain if it meets Discharge Minimization Technology (DMT) requirements for a Permit. To date, no information has been provided by IUC regarding the design or construction of this catch pond. Nor was any such information provided during the May 9, 2000 DRC inspection. However, it is anticipated that catch pond was constructed in a similar manner Memorandum May 11, 2000 PageT as the tailings cells at the facility. Therefore, it is likely that it is lined with a single FML. Consequently, additional compliance monitoring wells will be needed around this pond. 8. Acid Storage Tank - during the inspection, an above ground acid storage tank was observed in the northwestern most comer of the mill site, located north of the Process Wastewater Catch Pond. Immediately west of the acid storage tank was a concrete lined offloading pad where the acid delivery trucks offload acid. This offloading pad had a concrete surface, without berms, which drained into grated collection sumps. Mr. Deal stated that these sumps in turn gravity drained thru an approximately 10-inch HDPE pipe into Cell l. More detailed review should be given to both the offloading facility and the above ground acid tank in order to determine DMT requirements for the Permit. This effort can be completed during DRC review of the IUC Spill Management Plan, to be submitted by November 24,2000. 9. Alternative Feedstock at the Ore Storage Pad - during the inspection we visited the open-air ore storage pad east of the mill site. While there, Mr. Hochstein stated that: I ) approximately 90,000 tons of altemative feedstock from the Ashland project was stored in bulk form on the pad,2) approximately 3,500 tons of Cameco altemative feedstock was stored in 55-gallon drums on the pad, and 3) at a processing rate of about 1, 000 tons of feedstock per day, the current material in storage could feed the mill for about 90-days. 10. Four Wildlife Ponds - during the inspection we found 4 wildlife ponds located at the facility, each of about 2-acres in size. Two of these ponds were found about 100 yards or more east and north ofthe ore storage pad (Upper Wildlife Ponds). Two otherponds were found about 2,000 feet east and north of the northeast corner of Cell4.A. (Lower Wildlife Ponds). Two unlined ditches were also found during the May 9 inspection, one connecting the 2 Upper Ponds and a second connecting the 2 Lower Ponds. Several types ofphreatophyte and riparian plants were also observed at the margin of each pond during the May 9 visit, including willow and Russian olive trees, and cattails, among others. Waterfowl and song birds were also seen on the wildlife ponds and in the riparian habitat, respectively, during the visit. During our visit Mr. Deal reported that: l) the Upper Ponds were constructed in about 1990, while the Lower Ponds completed in 1994,2) all4 ponds were constructed by bulldozing native soils up and out of natural depressions while forming a small retention dike at each pond, 3) no liners exist under any ofthe 4 ponds; only uncompacted native soils and bedrock, 4) water stored in the ponds comes from a drinking water supply pipeline, constructed by the local water conservancy district, that runs from Recapture Reservoir north ofBlanding to the site along State Highway 191, 5) water arrives at each set ofponds via a westerly lateral from the main pipeline, 6) overflow from the northem-most pond exits into a ditch which in turn feeds the lower pond in each set, 7) no flow meters exist on the system to measure flows transferred into the ponds, 8) the ponds are fed manually by IUC staffwho periodically open Memorandum May 11,2000 Page 8 a valve on each lateral to transfer water into the wildlife ponds as needed, and 9) construction and use of the wildlife ponds has significantly reduced waterfowl visitation at the tailings ponds. The most significant finding regarding these 4 Wildlife Ponds, is that they may constitute a constant source of head and groundwater recharge for the uppermost aquifer. The operation of these 4 ponds along the eastem margin of the facility may explain the dramatic increase in groundwater levels seen in the last 5 years at well MW-4, found East of Cell 2. It is also obvious that the July, 1994 Titan Environmental Hydrogeologic Report made a glaring error in its omission of any of these Wildlife Ponds in its description of local groundwater conditions. As a result, it is clear that additional piezometers will be needed near these 4 Wildlife Ponds to characterize local groundwater flow directions. It is also possible that the influence of these Wildlife Ponds couldhave easily altered local groundwaterflowfrom apredominantly southwesterly directionto awesterly ornorthwesterly direction. If so, additional compliance monitoring wells will need to be installed along the westem margin ofthe IUC tailings cells in order to monitor local groundwater conditions and tailings cell perfornance during the operational phase of the facility. If it is found that these ponds did cause the recent dramatic increase in water level at the eastem margin of the IUC facility, then we will be forced to conclude that short vadose zone residence times are possible at the White Mesa site. Conclusions Field observations combined with a continuing lack of engineering design or construction data reinforces the staff s previous conclusion that Cell I has no leak detection system. Field inspection also shows that improvements could be made to the Cell2 slimes drain recovery system to minimize head conditions on the FML by addition of a modem transducer or float switch to the pump controller equipment. Similar controllers and a pump system could also be added to the Cell 3 slimes drain recovery system and operated to minimizeheadover the FML in that cell. Based on the current disrepair and neglect of the Cell 4A FML, lack of FML integrity indicated by historic LDS flows, inadequate FML design, small waste volumes currently stored there, and the apparent lack of adequate engineering containment for the vanadium salt residual left on the cell floor, DRC staff recommend that Cell 4A be: l) decommissioned by removal and disposal of the FML and vanadium salts left on the floor, and}) re-designed and re-constructed before use again for waste storage or disposal. Site inspection also found the existence of an un-lined Fly-Ash Pond at the facility. In order to minimize potential pollution of local groundwater resources, the upcoming Permit should require IUC to either close this facility with an adequate engineered cover system and compliance I Memorandum May 11,2000 Page 9 monitoring wells, or decommission the Fly-Ash Pond after removal and approved disposal elsewhere of the offending waste material. A Process Wastewater Catch Pond was also discovered at the IUC facility that stores and disposes of floor drainage from the mill and solvent extraction building at the site. Close review of the engineering design and construction will also be needed for this facility in order to determine adequate DMT. However, this review can be incorporated into review of the Spill Management Plan, scheduled to be submitted in November, 2000. Other spill containment related facilities can also be reviewed at that time, including acid and product storage tanks at the mill site. Four unlined Wildlife Ponds were also found along the eastern margin ofthe IUC facility, that may pose a source of man-made recharge to the uppermost aquifer. Operation of these ponds may have already dramatically changed local groundwater flow directions, by forcing local groundwater to flow in a westerly direction. This possibility must be carefully investigated before DRC approval of a compliance monitoring well network for the IUC facility. If it is found that these Wildlife Ponds have altered local groundwater conditions, then the DRC will be forced to: l) conclude that vadose zone residence time is short at the White Mesa site, and 2) require installation of new monitoring wells to adequately monitor the facility. LBM:lm attachments (20 photographs) cc: Larry Mizq DWQ Mike Layton, NRC - Washington, D.C. 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