ML20214K616
| ML20214K616 | |
| Person / Time | |
|---|---|
| Issue date: | 09/17/1986 |
| From: | Fliegel M NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Martin D NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| References | |
| REF-WM-54 NUDOCS 8612020377 | |
| Download: ML20214K616 (26) | |
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- 1@f ~sf J. (WM54) i JGrimm WMGT rf Aibr:him NMSS rf TMo SEP 171986 REstowning JTrapp MBell KCJackson WN54/WHF/86/9/15 J0 Bunting MHaisfield PSJustus WFord & rf MFliegel PDR MEMORANDUM FOR:
Dan Martin, Section Leader WMLU
- ""8 JForstrom TJohnson FROM:
Myron Fliegel, Section Leader WMGT
SUBJECT:
WMGT DRAFT COMMENTS ON THE GRAND JUNCTION DRAFT REf1EDIAL ACTION PLAN, TICKET WM-8675F Cur draft comments on the Grand Junction draft Remedial Action Plan are enclosed. At this, stage our corrrrents are preliminary and may change pending further review and additional inforrration gained durino site visits.
Furthermore, as per agreement between the project manager and my technical lead individual comments have not been reviewed as part of our quality assurance procedures, in order to meet your schedule needs. Contributors to this review were Willian Ford and Michael Young (ground water), Jonathan Forstrom and Ted Johnson (surface water), Joel Grimm (geology), Tin Mo (geochemistry), cnd Abou-Bakr Ibrahim (geophysics). Shculd you have any questions please contact William Ford (74697).
Original Signed By Myron Fliegel, Section Leader WM Rxcrd f!!e W " P nicci. [
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e Nac,Fe isra u s NUCLE An asculArOav CowuissiON vas wvat a TECHNICAL ASSISTANCE TASK CONTROL' DIVISION OF WASTE MAN AGEMENT, NMSS si66%uweta Phil Justus, WMGT & John Greeves, WMEG WM-54 CECi5'ONu%ef#LA%NtQ ACCQYP NQ p t.ou Malcolm R. Knapp, WMLU WM000054010E/MS-010 Pe$AS 54421 TASK TITLt Review of Grand Junction Draft Remedial Action Plan (DRAP)
TASK r,ESCmiPTION DOE has submitted the DRAP for our review and comment. To meet DOE schedules,I will need your input by September 15.
I also need to know the necessity of a site visit since the pile is being moved to an alternate site. (Any site visit should also include Slick Rock, Maybell, Green River, and possibly Rifle).
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WM54/MY/86/9/17 DRAFT GF00ND WATER COMMENTS ON THE DRAFT PEMEDIAL ACTION PLAN GRAND JUNCTION, COLORADO PART 1 0F 2
GENERAL COMMENT
S
,Po_s_sible Cross-river Contamination The DRAP states that groundwater acvcs vest-southwest and discharges into the Colorado River. Ecwever, several conditions ard stctements, contained in the DRAP, raise questions er tFe validitv of this statement and the possibility that groundwater may ficw scuth, under the Colorade Piver and impact water quality in tFe crea south of the river.
These conditions include:
1.
From cross-sections presented in Figures D.5.3, 0.5.4, and D.5.8, it appears that the alluvium-Mancos Shale contact dips south, toward the Colorado River. This lithologic contact may 4rfluence the flow direction, as seen in the scuthwestern direction of grourdwater flow.
2.
Contaminate plumes have been mapped and irterpreted as moving west, although there is a cicar rertbern compclent to the migration. The pessibility of southern micraticr cf tFe plume, similar to that ct, served north of the site, has not trer addressed.
3.
Figure D.E.!E indicates a saturated thickness of -alluviun beneath the riverbed of the Colorado River of perhaps ten feet.
This supports the prerise that southerly flowing groundwater dces rot recessarily discharge into the Colorado River. Therefore, it is possibir that crrurdwater flows beneath the river in the alluvial material, and nay irract potential' groundwater users in the area south of the Coloredc
' liver (an occurrence of grourdwater flow such as this has beer observed et another UMTRA Project site (00E, 1985)).
DOE has made no effort to verify that contamirated groundwater, near the processing site, fully discharces from the groundwater system.
Therefore, the possibility exists that grcundwater flows beneath the Colorado Piver and may impact tFe vater quality in the area scuth of the river. DOE needs to address tFis possibility by characterizing the quality of groundwater in this aree ard essessino possible impacts to consumers of potentially contanirated aroundwater.
6^
a M ll WM54/MY/86/9/17 Possible Northward Flowing Contaminants According to the DPAP, groundwater flows west-southwest and eventually '
discharges into the Colorado River, resulting in a finding that public health will ret be jeapordized. However, when interpreting data and informatict certained in the DRAP, groundwater in the Dakota Sandstone may be impacted by contaminated groundwater eminating from the processing site in the ellovial aquifer. TFis pessibility cannot be confirmed or denied, because data and information on the Dakota Sandstone have not been collected.
The following conditions support the deternination that additional informaticn needs to be collected:
1.
On page D-47, the DRAP states thet the Mancos Shale thins west of the Rte. E0 bridge (.5 mile), where the Dakota Sandstone subcrops with the alluvium. Therefore westerly #1cwinc groundwater, from beneath the tailings may reach this alluvium-Dakota Sandstone contact, and affect groundwater in the Dakota Sandstore.
Although the direction of groundwater flow in the Dakota Sandstone has not been established 4
in the DRAP or the EIS, page F-137 in the DEIS states that the Dakota Sandstone dips frcm south to north, with the recharge zcne probably located south cf the site. Using this information, potentially certemirated groundwater in the Dakota Sanastone should flow north, away from the zone of recharge, or at least maintain a component cf northern flow. Therefore, potential groundwater users may be affected by irgesting this water.
2.
Using data aveilable in the DRAP, NRC staff have determined that downward hydraulic gradients, from the alluvium tc the Dakota Sandstere, ray exist up to five feet. This potential gradient may be enough to promote downward migration of contaminated greurdwater, tFrcuc,h the Mancos Shale, before there is actual contact between the alluvium and Dakota Sardstone.
These conditions, when used in ccmbiration, lead to a hydrogeolcgic scenario in which contaminants n.ay impact the groundwater in the Dekett Sandstone either by possible downward migration through the Mancos Shale, caused by downward hydraulic gradients, or by direct contact of the alluvial materie.1 with the i
Cakota Sendstone. 00E needs to characterize the direction of groundwater flev in the Dakota Sandstone, so that the above scenario, and the scenario described in the DRAP can be ccnfirmed or discounted. Of particular inpcrtance is the 1
area adjerert to cnd west of the Rte. 50 bridge, where the Marcos Shale allegedly pinches cut.
This information should be capable cf substantiating the hydrogeclogic scenario proposed in the DRAP, and lead te subsequent 4..
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conclusions pertaining to aquifer restoraticn er institutional control of groundwater.
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DETAILED COMPENTS Section 4.3.7.. Page 50, Paragraph 3 In defending their decision that aquifer restoration is unnecessary, DOE states the hydrogeologic setting (i.e., rechcrge from the nearby Colorado River) would complicate the effort.
From this statement, DOE implies that recharge of relatively fresh waters into the aouf fer systcm would either hinder the restoration of the poor quality aroundwater, or increase the cost of restoration by pumping diluted groundwater.
It vculd appear logical, however, that a nearby source of recharge would improve the efficiency of the restoration if extraction wells were properly placed; the fresh water recharge could improve the cuality of the groundwater faster, and allow the restoration process to continue without the threat of the aquifer system dryiro cut. The success of the restoration, therefore, will be dependent on the design end pumpirc scheme of the well system. DOE shculd cualifv the statement that the hydrogeology of the site will ccmplicate the restoration ef#crt, with examples and justifications on how the option of restoration is infeasible.
Figures D.5.1.-D.S.4., Page D D-54 The DRAP provides cross-sections of the tailings pile and a base map for locating these cross-sections. However, tFe bcring locations from which these figures were develcped, are not included en the base map. These control points are necessary to deternine the accuracy of the cross-sections and their locations. Forecver, the lithology logs of the herings are not contained in the DRAP, or the EIS.
These sFeuld be included in the DPAP since remedial action plans are based, in part, on these logs.
?
Finure D.5.11, Page D-61 Figure 0.5.11 represents the monitoring well locations at the Crard Junction processing site.
Pcwever, there are discrepencies associated with this figure and Table D.5.6.
1.
The figure does not include the locations of all the monitor wells.
The wells not shown are uparediert, alluvial wells 711 and 712 and downgradient, alluvial well 738, fer wFich the water quality informatico is cbsent in Table D.5.6.
Figure D.5.11 should he
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_4 modified to include the !ccation of all the wells used in the e
monitoring system.
If the present scale of the figure cannot support inclusien of these wells, then an additional figure with an appropriate scale should be provided.
2.
The figure represents the location of menitor wells 591 and 596, but no information on well construction, water levels, or water quality is present in Table D.5.6.
Therefore it is inpossible to determine which strata is being monitored, er from which strata water samples were retrieved. Therefore, irferration associated with these wells should be included, or the figure shculd be modified to remove then.
Figures D.5.16-D.5.20, Page D D-67 Figures D.5.16 - D.5.20 in the DRAP represent water quality maps for several contaminants found in the greurdwater.
However, the ficures do not include the location cf tFe wells used in construction of these figures, making validation of proper contour line placement very difficult. The figures sbculd be r:cdified to include the well locations used to construct the map. Also, in Figures D.5.16 and D.5.17, the iso-concentration lines do not extend over the full study area, but taper off up-gradient of the site. Since the weter quality results are available for wells up-gradient cf the processino site, the iso-contration lines should be extended to reflect conteminant levels in groundwater in these wells.
Table D.5.5, Page D-75 During the monitoring period, both water lecc1 information and water quality results were retrieved from the meritor well network. However, in several cases, water samples were collected, but no water levels were recorded.
Interpreting the relationships between water quality and the water table elevation, from information ccliected using this groundwater monitoring method, is not defensible because correlating the two conditions ir the scoe time frame cannct be cchieved. Therefore, any comparisons or conclusions that utilized these data in combination may not be valid.
If available, these water leve!
c' eta should be included in the DRAP.
If the information is not available. 00E should assess possible effects on the interpretation of the flow regime and the proposed contaminant migration patterns. Future nonitcrirp activities should include recording water leve's frm wells whenever water samples are collected.
Section D.5.5., Page D-80 During the monitoring period from approximately PercF-September,1985, two dcwngradient shale wells exhibited enormous water level changes. The rarges of water levels, for wells 729 and 705 are 33.90 and 21.99 feet; during this time
I'I) 2 bd'sii WM54/MY/86/9/17 I period, water quality also varied considerably. Nearby wells, however, did not experience changes in water levels or contaminant levels to this degree. These anomolous readirgs may indicate either external influence on the groundWster system by humans, or lack of accuracy and quality control en the part of the technician' collecting the samples.
DOE should explain the cause of these perturbations.
Section D.6.6., Page D-154, Paracraph 3-4 The DRAP states that comparisons of water quality results from samples taken at Ctrre ord Fruita indicate no effect of the Grand Junction tailings on the Colorado River.
However, the CF.AF ard the E!S (D0E, 1986) contain no data te confirm this. Also, there was no mention of where Grand Junction renoves veter from the Colorado River for their municipal water supply. A withdrawal point downstream of the tailings could result in possible exposure to the public to contaninated groundwater. The 00AP should indicate where Grand Junction removes water for their municipal water supply tr.d should provide the information that confirms the claim that the Colorado Piver is unaffected by the tailings.
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WM54/WHF/86/9/11 ORAFT GROUND WATER COMMENTS ON THE DRAFT REMEDIAL ACTION PLAN GRAND JUNCTION, COLORADO PART 2 0F 2
GENERAL COMMENT
Section 3.5, GROUND WATER, Page 34 The DRAP describes ground water pollution at the Grand Junction site, but does not indicate what will happen to ground water pollution left at the processing site. Since the decision to leave ground water contamination behind is a consequence of moving the tailings, the DRAP should incorporate by discussion or reference a description of the effects of such action. The DRAP should also justify, according to agreements in the Memorandum of Understanding between the NRC and 00E, why ground water restoration is or is not needed.
DETAILED COMMENTS Section 3.5, GROUND WATER, Page 34 The DRAP describes the ground water pollution at the Grand Junction site, but does not evaluate the consequences of abandoning the existing ground water pollution after reclamation activities, as required by the Title I standards and the Memorandum of Understanding between the NRC and the 00E. However, the draft Environmental Impact Statement for the Grand Junction site does contain I
information on this subject. Therefore, the following comments refer to the appropriate sections of the draft Environmental Impact Statement that deal with the effects of residual ground water contamination at the Grand Junction processing site.
1.
DEIS, Section F.3.2.2, Water-quality impacts, F-147 When the tailings are relocated to the Cheney Site, impacts to water quality near the processing site would be due to residual contamination in the ground water and possibly sorbed or precipitated contaminants in the alluvium. A mixing cell model was used to evaluate the persistence of residual contamination.
In using this model a number of assumptions were made. However, the text does not indicate if the model overestimates or underestimates the length of time it would take the aquifer to restore itself by natural methods.
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WM54/WHF/86/9/11 The text should clarify whether this model is providing conservative or realistic results and justify the conclusion.
2.
DEIS, Section F.3.2.2, Water-quality impacts, F-147 Since the tailings will hcve to be dewatered prior to excavation and the pumped water may have to be treated prior to discharge to the Colorado River, significant clean up of the tailings may occur as a result.
In estimating the impacts of leaving residual ground water contamination at the Grand Junction site, the effects of dawatering the tailings on the ground water contamination should be included in the discussion or analysis.
3.
DEIS, Section F.3.8, AQUIFER RESTORATION, F-168 In discussing the possibility of ground water restoration at the Grand Junction processing site the text states that " plume capture near the Grand Junction tailings is complicated by both physical and cultural features." As one example, the text states that pumping the shallow aquifer would induce flow from the Colorado River that would dilute the contaminated ground water. Therefore, an increased volume of water would be captured and treated, thus increasing the costs for each activity would be increased. The problem with this statement is that it is too generic, since the conclusion is too dependent on the specific design of a particular ground water restoration scheme. For example, if ground water extraction points are located at a distance from the river and more towards the center of contamination, the river could provide a source of clean water to more quickly effect restoration rather than adding to the cost. The text should better explain its conclusion (for example, by defining the contaminate plume to be cleaned up and its relation to the proposed restoration method) or not assume that the river will necessarily increase restoration costs.
4.
DEIS, Section F.3.8.5, Degree of human exposure likely to occur, F-174 In discussing the health effects that could occur from residual contamination at the Grand Junction processing site, no discussion is included of what measures, if any, are needed to protect the populace from using ground water under the tailings site once it is released to unrestricted use and until it has been naturally restored in the next 100 years.
DER WM54/WHF/86/9/11 5.
DEIS, Section F.3.2.2, Water-quality impacts, F-147 The contaminated material excavated from the Grand Junction '
processing site will be replaced with material excavated at the Cheney site.
This means that a different geologic material will occupy the Grand Junction processing site after the completion of reclamation activities.
This material will have different hydrologic and geochemical properties than the previous materials.
Accordingly this new material may have positive and negative effects on the ground water quality under the site and may effect the ground water contamination left behind after reclamation activities. The DRAP should include a brief discussion of the effect on the ground water quality, positive or negative, from the fill material that will be placed at the Grand Junction processing site.
Section D.5.2, FLOW REGIME, Page D-48 Wells 711 and 712 were used to establish background water quality for th'e alluvial aquifer at the Grand Junction mill tailings site. However, no figure is provided to locate these wells with respect to the site and other land uses or surface water bodies. Since these wells are very important in determining the effects of any ground water impacts, a location map should be provided.
Tables D.5.6, Ground Water Quality Data by Location, Pages D-83 to 0-150 Cation / anion balances are a part of DOE's water quality assurance program.
However, NRC staff spot checks for some of the samples in Table D.5.6 yielded unacceptable balances, which implies an inaccurate analysis for the major ions.
Therefore, cation / anion balances for each sample should be included in Table 0.5.6 and the text should describe the validity of the chemical data if there has been a lapse in the DOE quality assurance sampling and analysis program.
TABLE D.5.6, Ground Water Quality Data by Location, Page D-110 An analysis for uranium collected on 3/22/85 from well 739 has a value of 8324 pCi/L.
This seems very high and suggests significant uranium contamination off site. The DRAP should explain the occurrence of this high value and describe the environmental effects and any ground water remedial actions that will be required.
n
DRAFT WM54/A!/CE/9/17.
DRAFT SEISMIC COMMENTS ON THE DRAFT REMEDIAL ACTION PLAN GRAND JitCTICN, COLORADO GENEPAL COMMENT The RAP does not discuss any geophysical survey which may have been used to support the site investigation findings. Discuss the type of geophysical surveys conducted.
!f nn surveys are conducted explain the reasons.
DETAILED COMMENTS Section E. 3.6, Seismotectonic Setting, Page E-42 In the RAP it is stated that "the stress fie ds criented differently than the 1
modern stress field in the interior cf the Plateau".
Provide a map showing the stress field orientations in the Colorado Plateau as compared to the surrounding provirces, and discuss if the stress fields are used in delineating the different seisnotecteric provinces.
Section E.3.6, Western Mountain Province, Page E-48 In the RAP it is stated that, " faults asscciated with evaporation flowage or sclution which cut Neogene rocks are not considered to be capable of pererating earthquakes of magnitude greater than 4 or 5".
Provide justificatiers fer this statement.
Identify the closest fault of this type to the site and provide the estimated magnitude and compare to the design earthquake.
,Section E.3.7.4, Analysis of Seismic Risk, Page E-53 Campbell (1981) atterxction relationship is based mcstly on earthquake data from California.
Provide the rationale for using this relatier. ship for Grand Jur.cticr.
Section E.3.7.4, Determination of Floating Earthquake Magnitude, Pace E.57 In the PAP it is stated that "the FE ragnitude should never be greater than the ME".
Provide the rationale for this staterert.
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Section E.3.7.4. Determination of Floating Earthcuake Magnitude, Page E.59 In the RAP it is stated that "In accordance with seismic design procedures commonly u~ sed in the siting of ruclear power plants, this event is assumed to occu" at a radial distance of nine miles (15 km) from the site". The distance of 15 km has been based on the average of ensemble of earthquake reccrds, "having similar physical properties to the site, used to generate site specific spectra for unclear power plant sites and this distance may vary from one site to the other.
Provide the rationale for choosing nine miles (1F In1 es the distance from the site to the floating earthceake to calculate the acceleration in the Grand Jurction DRAP.
Section E.3.7.4, Faults and Ericenteral Compilation, Page E.63 Kirkham and Rogers (Colorado Geological Survey, Fulletin 43, Plate 3, 1981) identified faults 1,3,a,7.8,9 and 17 as potentially active faults.
In the RAP it is stated that these faults are not proven to be capable.
Provide supporting field cviderces and aerial photos to suppcrt that these faults are not capable.
Section 3.7.4, Cheney Reservoir Site Lineament, Page E.65 In the RAP it is stated that this lineament is not the result of faulting.
Provide the field eviderces and aerial photos which would support this statement.
Ecctier 3.7.4, Epicentral Compilation, Page E_67 In the PAP it is stated that the earthquake of November,1871 appears to he related to Fault 6.
If this is the case it sFruld be considered capable.
Section E.3.7.4, Recommended Seirric Design Parameters, Page E.67 Identify the references and the ferrulae used to estimate the magnitude ard the acceleration from fault 8 and the rationala fer choosing these formulae.
Indicate if the fault tyre is considered in estimating the magnitude and, the exact distance of the fr.uit from the site.
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WM54/AI/86/9/17.
Section E.3.8.4, Recommended Seismic Desien Parareters, Page E.67 In the Draft Environnentel Impact Statement (EIS) (DOE /EIS-0126-D, Vol.II, P.
E-41, March 1986) it is stated that "High accelerations may result from the I
occurrence of earthouakes of magnitude as higher as 6.6 on previously unknown faults within less than five miles cf the sites".
Based on this staterent should the design earthouake be located at a distance less than 5 miles frcr
)
the site.
If r.ct, discuss with rationale.
l Table E.3.5, Earthquakes of M d.0. Pace E-89 This table lists earthquakes up to 1981. Update this table to cover recent scisric activities in the aree ard provide a map showing the locations of these earthquakes.
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DRAFT GE0 MORPHOLOGY COMMENTS ON DRAFT REMEDIAL ACTION PLAN GRAND JUNCTION, COLORADO 1.
Section E.3.2, Regional Geomorphology, Page E-25, paragraph 1 Glacial moraines located near Ridgway, CO, are mentioned with reference to fluvial terraces in regional drainage basins.
This statement should refer to a map in the RAP indicating the location of Ridgway and the glacial deposits.
In the same light, DeBeque, C0 (page E-26) is not found in the figures.
In all cases, geographic locations referred to in a report should be located on a figure within the report.
2.
Section E.3.2, Regional Geomorphology, Page E-25, paragraph 2 A potassium-argon date of 9.7 m.y. is incorrectly assigned a Pliocene age.
Reference to the wrong epoch misleads the geological discussion.
This age should be reported as Miocene (see Palmer, 1983).
3.
Section E.3.2, Regional Geomorphology, Page E-25, paragraph 2 Based on radiometric age data for Grand Mesa, an " average" erosion rate has been calculated for the Colorado River valley.
The calculation makes an assumption that the valley has lowered to its present level only recently and is zero years old relative to the mesa age.
This assumption is not necessarily valid.
An average erosion rate cannot be calculated unless a constraining age is known for the valley as well as the mesa.
Therefore, the calculated erosion rate should be reported as a minimum rather than an average.
4.
Section E.3.2, Regional Geomorphology, Page E-28, paragraph 3 Citation of Hunt (1969) is missing from the reference list.
Therefore, NRC cannot review the adequacy of discussions of scarp-retreat calculations at Book Cliffs.
5.
Section E.3.2, Regional Geomorphology, Page E-28, paragraph 3 Slope retreat rates of 23 m per 1000 yrs are reported for the Book Cliffs by Hunt (1969?).
The DRAP discounts these calculations only because they 4
WM54/JG/86/9/17/1.-
seem exceptionally rapid.
The DRAP should not simply discount these data without an explaination.
Justification for an assumption that the calculations are erroneous should be based upon quantitative data which refute the rapid rate.
Such quantitative evidence is not cited in the DRAP.
6.
Section E.3.2, Regional Geomorphology, Page E-29, paragraph 2 Use of the terminology " detached pediment" is unclear and needs definition or illustration.
Even though graphic projection of longitudinal profiles of the pediment surfaces may be approximate and inconclusive, they would be instructive for the reviewers' understanding of the scale of pediment extent and of topographic relations.
7.
Section E.3.3, Climate and Vegetation, Pages E-31 to E-36 The DRAP provides conversions of temperature-change data from degrees Celsius to Fahrenheit and elevations from feet to meters.
Some of these conversions are erroneous and require revision for accuracy.
8.
Section E.3.4, Site Geology, Page E-36, paragraph 2 Appendix E here refers the reader to Figures 3.13, 3.14, and 3.15 in volume 1 of the DRAP.
These figure do not exist.
Therefore, the reviewer cannot comment on stratigraphy of surface P3 deposits.
The reviewer, however, believes the reference is to Figures 3.6, 3.7, and 3.8.
If this is so, the figures are duplicated in Appendix E (Figs. E.7.2, E.7.3 and E.7.4), and reference to another volume is unnecessary.
9.
Section E.3.4, Site Geology, Page E-38, paragraphs 2, 3, and 4 The DRAP suggests differentiation of geomorphic surfaces P3a and P3b based j
upon separate criteria:
- 1) two separate cycles (ages) of pediment
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formation, or 2) different types of depositional processes for the associated alluvial deposits.
The discussion, however, does conclude which criteria accurately distinguish the two surfaces nor does it indicate which criteria were actually used for the classification.
If the classification is based upon separate ages, use of one number designation, P3, is inconsistent with the method of surface nomenclature.
WM54/JG/86/9/17/1.
Therefore, the final RAP should clarify the age relatforships and draw a conclusion regardfro relative age, or it should eliminate the inference of temporal distinction between surfaces P3a and P3b.
If the classification is based uper surface morphology, the final PAP should provide evidence that the mcrphologies are due to original depositional processes and are not related to recent surficial processes.
Varying surface morphologies related to recent processes would indicate incipient surface erosion and irstability.
- 10. Section E.3.4, Site Geo'ogy, Page E-38, paragraph 3 The text reports on weakly developed and thin textural B horizons in the soil profiles on surfaces P3a and P3b. On page E-36, however, the DRAP cites "strcng caliche cementation" at least 1 m thick in the same deposits. Well-develcped calcic horizons ir ar area 'ree of carbonate parent materials scorests long-term surface stability, while lack of well developed B horizons suggests lack of such stability. This centradiction must be further explained to determine that the Cheney Reservoir site will provide geomorphic stability.
11.
Section E.3.4, Site Geology, Page E-38, paracraph 3, 4, and 5 In the discussion c' surface morphology, desert pavement, and desert varnish in the Cheney Reservoir site area, references te Pohrenwend (19841 are tenuous or inappropriate for several reasons:
11 The Dohrenwend (1984) reference is a guidebook containing several papers which address the above subjects. General citation of er editcr is irappropriate and delays location of the desired information. The DRAP should cite specific works within the guidebook.
2)
Original bar-ard-swale depositional morphology was identified on surfaces P3a and P3b from aerial photography of the Cheney Reservoir site. The DRAP citos PcFrerwend (1984) using relict bar-ard-swale morphology as an indicator of relative age.
Table E.3.3 gives a comparison of surfaces P3a and P?b but provides no quantitative descr4ptior of the bar and swale morphology.
The specific reference to be cited is Wells and others (1934) regarding alluvial fan deposits at Silver Lake, CA.
This peper
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DRAFT WM54/JG/86/9/17/1.
includes detailed field data indicating latest Holocene deposits
' exhibit less than 1 m original depositional relief and provides that bar-and-swale relief decreases with age.
.From the above discussion, the ORAP's interpretation of surface morphology seems tenuous.
Citing Wells and others (1984), the reviewer maintains that bar-and-swale morphology could be tentatively identified from aerial photographs, but that morphology with less than 1 m relief requires field observation and measurement for verification.
The ORAP does not report this.
3)
Existence of well developed desert pavements and desert varnish is generally recognized as common in hot arid climates, like the Sonoran and Mojave Deserts.
Therefore, discovery of these features in a semiarid area like western Colorado may be problematic.
4)
The DRAP draws comparisons between basaltic pediment deposits on surface P3 and " basalt-bearing" deposits discussed within Dohrenwend (1984).
The specific paper concerned with fluvial deposits and desert pavement is the Wells and others (1984) study at Silver Lake, CA.
The deposits studied are derived from plutonic and metamorphic rocks and Tertiary gravels (Wells and others, 1984, p. 72) and are not composed of basaltic material as suggested in the DRAP.
Processes of desert pavement formation and their rates are not necessarily correlative between the two types of deposits.
5)
Depiction of the climate of Grand Junction area as " roughly similar" i
to the hot arid climate of the eastern Mojave Desert is tenuous, at best.
The ORAP should probably attempt to make its geomorphic comparisons with areas of similar, semiarid climate within the Colorado Plateau.
12.
Section E.3.4, Site Geology, Page E-39, paragraph 2 The DRAP credits alluvium on pediment surfaces with protection of bedrock against erosion.
The fact that channels have not formed on a particular pediment remnant, however, is likely a factor of both basin morphometry and underlying surficial deposits.
Furthermore, the concept is discredited because pediment surfaces in the area occur as relatively small remnants and occur at many different levels, indicating that the pediment surfaces are indeed abandonned and degraded over time.
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, - - -, -.. ~ - -. - -, _,. _ _. ~. _. - - - - -,. -. - - - - -,...,,,. -
BRAFT WM54/JG/86/9/17/1 The concept of pediment deposits being treated as distinct entities, separate from the geomorphic surface itself, and providing geomorphic stability is an untested one.
Generally, pediments and their surficial deposits are recognized as a result of geomorphic stability, not a cause.
The final RAP should attempt to verify the concept in the geologic literature.
13.
Sectio E.3.4, Site Geology, Page E-49, paragraph 2 The DRAP makes a conclusion that length of an incised channel is directly related to the basin area which it drains.
However, no morphometric data are presented to support this.
In the Piceance basin north of the site, Patton and Schumm (1975) have shown that the mere occurrence of incised channels is a factor not only of drainage area, but also of valley slope.
To predict likelihood of future geomorphic stability at the Cheney Reservoir site, DOE may wish to consider a similar analysis cf gullied and ungullied channels in the site area.
The analysis may assist a determination that a threshold condition does not exist for channel instability on surface P3.
14.
Figure E.3.6, page E-76 The geomorphic map of the Indian Creek area shows nine geomorphic surfaces and the text (page E-37) explains the techniques employed for identifying the surfaces.
Existence of nine surfaces suggests very complex geomorphic history at the site.
The DRAP, however, has not provided or explained the data which resulted in differentiation of the surfaces.
Therefore, NRC review cannot address the potential impact of past geomorphic history upon stability of the site, especially surface P3.
The types of required data include:
1) projected height above local base level (Indian Creek) 2)
surface orientation 3) deposit descriptions (stratigraphy, grain size, thickness) 4)
soil descriptions (weathered pedogenic profiles) 15.
Figure E.3.6, page E-76 The geomorphic map of the Indian Creek area leaves a number of areas near l
the proposed site unlabeled.
Whether these areas are pediment surfaces, hillslopes, or active washes, they need to be so designated.
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REFERENCES CITED Dohrenwend, J. C., ed., 1984, Surficial geology of the eastern Mojave Desert, California: Geological Society of America 1984 Annual Meeting Field Trip 14 Guidebook, 183 p.
l Palmer, A. S.,1983, The Decade of North American Geology 1983 geologic time scale: Geology, v. 11, n. 9, p. 503-504.
Patton, P. C. and Schumm, S. A., 1975, Gully erosion, northwestern Colorado:
a threshold phenomenon: Geology, v. 3, n. 2, p. 88-90.
Wells, S. G., McFadden, L. D., Dohrenwend, J. C., Bullard, T.
F., Feilberg, 8.
F., Ford, R. L., Grimm, J. P., Miller, J. R., Orbock, S. M., and Pickle, J. D.,1984, Late Quaternary geomorphic history of Silver Lake, eastern Mojave Desert, California: an example of the influence of climate change l
on desert piedmonts, in Dohrenwend, J. C., ed., Surficial geology of the eastern Mojave Desert, California: Geologic Society of America 1984 Annual Meeting Field Trip 14 Guidebook, p. 69-87.
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DRACT GE0CHE!!ISTRY COMMENTS ON THE DRAFT REMEDIAL ACTION PLAN GRAtD JUNCTION, COLORADO
GENERAL COMMENT
Upon completion of the review of the DOE's DRAP the WPGT, Cecchemistry staff found that the DOE has neither taken into consideration nor addressed the potentially adverse short term and long term effects of geochemical processes (due to the intrinsic geochemical disequilibrium of the unconditoned tailiros) which could contribute to the physical instability and potential breach of the radon barrier and migration of toxic contaminants ct ary cf the UMTRAP sites.
It has recently come to the staff's attention that studies of abcut twenty inactive uranium mill tailings sites by a CCE centractor (Markos 1979, Markos and Bush, 1980, Markos and Bush 1981a ard Parkcs and Bush 1981b, 1983) indicate that salts with sulfate and chlcrive are mainly responsible for the upward migration of contamirants in the tailinos raterial. ftany of these salts are deliquescent or hyqrescrpic. As such, they are able to absorb moisture from both the interstitial atmcspbere of the tailings and the rearby water table.
This process, ccmbined with the dry conditions on the surface of the tailings, creates an _ upward flux of salt migration, which in turn transports certeni-nants. Both radioactive and chemically toxic icns such as U, Ra, Pb, V, Cd, ard Aq move together with the major constituents of the Na,Ca, K, Cl, and M salts.
Field studies shew that the concentrations of contaminants in the prhcipitating salts on the surface o' tailiros are several times to several orders of raonitude higher than in the underlying tailing material.
For example, Markos and Cush fl.9PO) found the association of Pa with the movement of Nacl and other salts er Cl to the surface of the tailings. This phenomenon is in good agrerrert with the experimental s'udies listed in the Geological Survey Circular 814 (Landa, 1980).
Further, Markos and Bush (1980i cbserved that the urward rovement of salts and centaminants are present in all the tvrnty tailings they studied during their field investigations.
These selts crd contaminants pnve through the protective covers and dikes o' the tailinos.
The observed profound effects of these salts are:
(1) devcirrrent of osmotic pressure,
(?)
liberation of gases within the tailings pile, (3) generation of heat by exothermic reactions, (4) desiccation of areas with lower salt content resultirq in desiccation
- Cracks, (5) blackening (oxidation?) of the surface of some species of vegetation (possibly due to oxidizino cases?i, (6) dissolution of silicate materials in contact with interstitial or soil
2 moisture solutions of high ionic strength and low pH (high acidity), and, (7) growth of crystals or precipitation nodules.
Osmotic pressure is significant for two reasons.
It is a mode of transport of contaminants to the surface.
It also represents a physical force to disrupt structures such as dikes of non-ore materials around tailings, soils, gravel and asphalt covers on the tailirgs by forning boils and cracks, thereby loosening the material which beceres highly susceptible for erosion. According to Markos and Bush (1981) the boils on the surface vary in diameter from less than a meter to several tens of meters and in height from a few centimeters to occasionally over a meter. Concentration of contaminants. including radio-nuclidr.s. cre elevated in these boils relative to the adjacent areas of tailings. Salts of different kinds usually precipitate en boils.
Active chrical reactions in the tailings can form various gases.
For example, hydrogen sulfide gas was detected in wells on the tailings in Cannonsburg, Pa.
Cases are expressed in formation of various size boils on the surface.
especially in slime areas. The escapir.g gases create flow structures in teilings materials and may be evidence for considerable physical forces. These flow structures rey act as pathways for the direct emanation of hazardous radon gas towards the surface.
The generation of heat by cycthermic reactions occurring within the tailings pile could accelerate the movement of radon and other gases towards the surface.
Crystal grrwth or precipitation nodules of salts result in volume changes.
Urter con'ined physical conditions, increased volumes may exert considerable forces. The effect of these forces have been observed on dikes uhcre Frulders have been disincated by growth of crystals and on the experirental asphalt cover on part of the Grand Junction tailings which has bccr brnken up by growing precipitatien nodules of salts.
The rate uf upward revement of salts within a tailings pile is relatively rapid. A year-round observation of salt novements in the Vitro tailings pile in Salt Leke City, Utah, and the tailings pile in Grand Junction, Colorado, irdicates that salts removed from the surface by rainfall through dissolution er runoff have been replenished a few months later. Although the distarre of trnel n' ralts in their upward movement for a given tire has not been presently established, the curve of salt distribution with depth arv the constant retorcrution of the salts suggest a continucus process.
This process will continue until an equilibrium is established. Lateratory experiments resulted in a movement of salts over a distance of I centimeter within a period of 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> at ambient room temperature conditions.
Water soluble salts have a profound effect on growth of vegetation. During the time of seeding and growth of vegetation, sprinkling systers are set up on tailings. Constant or exter.ded watering of the surface of teilings suppresses
3 the salts and washes them dern below the root system. After stopping the sprinkling, salts begin to move t..<ards.
After a few years of movement, the salts reach the root system ard destroy vegetation as has been observed'en several tailings piles.
Another role of selts is the creation of a chemical environment such as very low pH (1.8-3.5) and the supply of anions, particularly sulfete, to other geochemical reactions such as dissolution of silicate and clay minerals.
The icng-term stability of clay and silicate ninerals represents another arca of concern. The hydration energy of deliquescent and hygroscopic salts may have a sirr,i'icant influence on dehydration of clay ninerals. Chemical stability of clay and silicate minerals with respect to time is also relatively unknown. Thermodynamic stability of clay and silicate minerals under the pH conditions in roany tailings is very low. Acids may attack and destroy clay minerals. Markos and Bush (1080) aisc found that the various types of clay and silichte minerals have considerable differences in stability with respect to pH conditions. This night be of concern in terms of the long-term perfor-mance and stability of the ratcr barrier or the impermeable clay liner if one is proposed.
Dissnlution is an important process in tailings which results in a volume change. Flux of water through the tailings dissolves soluble selts easily.
The disselved salts move either by diffusion or by water transport. As water mcVes trward the surface with the terrperature gradient, evaporation causes eversaturation, and part or all of the solute precipitates. Transrcrtation in response to differences in chemical potentials causes a redistribution of material and volume within the tailings.
Silicate arc'/cr clay materials in contact with waters of high ionic strength and low pH may also dissolve creating large solution cavities and subsiderce er collapse of the affected parts of tailings piles.
Both dissolutico erd icosening of material can result in extensive piping and collapse of dikes protecting tailings.
These, in turn, continue in development irto erosional features and/or destruction of cover or protective materiels.
All these phercrcnon have been observed in all the tailings investigated, but the magnitudes expressed dif fer from one tailings pile to arother.
The overall effect of soluble salts in the tailings is very important. They establish a water circulatory system in the opposite direction to gravity.
They create an envirormert vhere many metals are highly mobile. The salts tend to move to the surface of the tailings carryire errtaminants which can enter into the surroundings by surface ernsional processes such as wind and runoff.
The salts are corrosive, and they con move through cover materials and tend to destroy vegetation nr the surface of the tailings.
The f!RC staff's position is that any containrent technology proposed by DOE in this DRAP for Grand Junction and ir future ORAPs should assess and consider the above results of the geocherica' study of the twenty inactive uranium milling
4 sites conducted by liarkos and Bush for DOE (Markes and Bush, 1983, 1981a,b, 1980 and 1979).
Engineerire designs for protective actions must be designed to I
withstand physical forces caused by chemical reactions in the tailings.'
Containrent practices, designed in a way to circumvent or eliminate the forcr:s prcduced by the chemical interactions in tailings, are necessary for adecuat.e protection of the environment.
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5 DETAILED COMMENTS t
Section B.1.7 Embanknent Construction, p. B-1 The DRAP states that the stabilized tailings pile will be designed to provide long-term stability, and mirimizc radon emanation and groundwater contamina-tion.
It is not clear how the design objectives of long-term stability, and minimization of radon emanation and grourdwater contamination (for periods of 200 to 1000 years after the preposed remedial action 1 will be accomplished.
This is because the design of the Cheney Site and the precess of stabilization of the tailings piles as described in this DRAP did not consider or address the short and long term impacts of the geochemical processes mentiened in our i
General Comments section. These geochemical processes could contribute to the physicel instability and potential breach of the radon and other superimposed minimal covers as illustrated by the results of the extensive POE contractor research study of the gecchcnical impacts of about twenty inactive uranium mill tailings sites.
The revised DRAP should describe clearly how the tech-nological controls for prctective action will be designed or utilized to withstand the disruptive physical forces ceused by the geochemical reactions in the tailings.
4 Section B.6 Radcr Parrier, Subsection B.6.1 Sumary p. B-29 The DRAP only considers the barrier (about erly 1.5 foot thickness of clean soil) to attenuate raden emissions and resiuce the potential inhalation or direct radiation doses to individuals that may occupy the surface of the site.
The DRAP had ret addressed the preventive neasures to control or prevent the migration of other toxic contaminants such as, uranium, radium (which could ruttorrtively transform to radon), lead, vanadium, cadmium and silver, due to the geccFenical processes described by Markos and Eush (1.981a, b). The revised DRAP should consider and address the appropriate eff'uont/ rertaminant control measures to prevent migratier cf these toxic contaminants or to mitigate their effects on the environment.
Section b.6.2, Conceptual Design, p. D-29 l
The NRC staff feel that the conceptual design of the radcn barrier and superimpcsed covers as described or proposed in the DPAP is inadequate to ensure both short tern and long term stability of the site and prrtection of l
public health and sa'rty and the environment. The revised DRAP should describe in detail hcw the tallings will be stabilized ar.d Few tFe design of the radon Sarrier and superimposed revers will take into consideration the DOE study results provided by Markos and Bush.
Section P.6.7, Moisture Content, p. B-33 j
The first sentence of this section states: "The long term meisture content of the cover naterial Fat tren estimated at 17.5 percent and the tailings at 10 i
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6 per cent." Judging from the results of the Markos and Bush stt. dies, the above relative conditions of moisture contents for the cover material and the toilings with highly hygrescopic salts will draw moisture from the coveF material, cause cracks in the radon cover, release radon, and allow other contaminants to migrate to the surface of the tailing site.
The revised DRAP should describe how the DOE plans to ritioate these problems.
Section D.3.6 Geologic Hazards, Subsection D.3.6.1, Geomorphic Hazards, Erosion by other precesses, p. 0-30 The second paragraph of this subsection described a large sinkhole, about 25 feet wide by 35 feet long and four to five (4 to 5) feet deep, which has evidently devcirred within the last few years near the north edge of the tailings pile. With regard to this large sinkhole. the CPAP stated:
"The sinkhole showed evidence of recent expansion during on-site reconnaissance in October and November of 1984." Further, within 50 feet to the east of this feature, the third paragraph described several smaller sinkholes, with dicteters of three to five feet and from three # pet or more in depth. The DPAP states that the cause of these large and small sinkholes is not known and cerjectured that an underground cavity may have existed due to previous construction.
However, it is possible that the geochemical procester of dissolution of salts cod subsequent dissolution of silicate materials by soil moisture solutions of high ionic strength and low pH observed by.Parkos and Bush (1981) is contributing to the volume chances within the tailings piles or cover material to eventually create large solution cavities and subsidence or collapse of the affected parts of the tailirgs or cover materials.
The DOE should investigate the cause of these sirkholes and describe the remedial and protective actiers that will be taken to prevent the formation of these on-site erosional features acair at the proposed Cheney relecation site.
Section D.3.6. Geologic Hazards, Subsection D.3.6.1, Geomorphic Hazards, Erosion by cther processes, Too paraorepF, p. 0-31 This paragraph states:
"Burrcwirc by prairie dog colonies is widespreart, (specially near the northwest corr.er of the site.
This causes disruption and dispersion of the clay cap and contributes te crcsion of the area. Wind gusts were observed dispersire raterials brought to the surface in burrows during the on-site investigation."
It is very likely that the materiels brought tu the surface in burrows are contaminated with toxic materials from the mill tailings. The DOE shoule address in the revised DRAP the remedial /pretcctive notreres that will be taken at the Cheney relocation site to prevent sini'ar disrupticn and dispersion of the clay cap, erosion of the area and atmospheric resuspension or hydrolegic dispersion / runoff of the potentially contaminated materials brought to the surface in burrows.
o REFERENCES G. Markos and K.J. Bush,1983, " Geochemical Investigation of UMTRAP Desfgnated Site at Grand Junction, Colorado." prepared by Geochemistry and Environmental Chemistry Research, Inc., Rapid City. South Dakota, for the U.S. Department of Energy, UMTRA Project Office, Albuquerque Operaticos O'# ice, Albuquerque, New Mexico. DOE /WMT/0231.
G. Markos and K.J. Bush, 1981a, "Physico-Chemical Processes in Uranium Mill Tailings and Their Relaticnship to Contamination," pp.99-114, Paper presented at the Proceedings of two OECD Nuclear Energy Agency Workshops on:
"Geomorpholooical Evaluction of the Long-Term Stability of Uraniun Mill Tailings Disposal Sites and Uranium Ore Processina/ Tailings Conditioning for Minimizing Long-Term Environmental Prebirns in Tailings Disposal." Colorado State University, Fort Ccllins. l'SA, October 28-30, 1981.
G. Parkos and K.J. Bush,1981b, "0yramics of Tailings to be Considered in Disposal and Containment Practices." f report on U.S. DOE Peer Review Panel Discussion on results of a DOE contractor Study on twenty (20) inactive uranium mill tailings sites.
Persoral Communication from Dr. Gergely Markos of the Research Institute for Geochemistry and Environmental Chenistry, Rapid City, South Dakota to Dr. Tin Mo, Radioactive Waste Standards Branch, Office of Dadiation Programs, U.S. Environmental Protection Acency, Washington, D.C.
G. Perkos and K.). Bush, 1980, "Pelationships of Geochemistry of Uranium Pill Tailirrs and Control Technology for Contairment of Contaminants" Paper presented at the Second U.S. Department of Energy Envircr. mental Centrol Symposium, March 17-19, 1980.
Gergely Markos, 1979, " Geochemical Pobility and Transfer of Contaminants in Uranium Mill Tailings," in Proceedings of 2nd Syrpcsium on Uranium Mill Tailings Managemcrt, Colorado State, November, 1979.
Lar.da, E.,1980, " Isolation of Urerit.n Hill Tailings and their Compor.ent Radionuclides from the Biosphere-Seme Earth Science Perspectives. Geological Survey Circular 814, 32p.