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Comments and Recommendations Submitted to Environmental Assessment Panel Reviewing Decommissioning Proposals for the Elliot Lake Uranium Mine Tailings Management Areas

Prepared by
Wm. Paul Robinson, Research Director, Southwest Research and Information Center
P.O. Box 4524, Albuquerque, NM, 87106 USA
phone: 505-262-1862/fax 505-262-1864
e-mail: sricpaul@earthlink.net

On Behalf of Northwatch, P. O. Box 282, North Bay, ON P1B 8H2 Canada
phone 705-497-0373/fax 705-476-7060

Submitted November 15, 1995

Text only, appendices available in hard copy by request from Southwest Research and Information Center

1. Overview and General Comments
   1. These comments have been prepared at the request of Northwatch, a community -based organization with offices in North Bay, Ontario. They address a wide ranging set of concerns, reflecting the large scale of the facilities and the long-term, essentially permanent hazardous material isolation and containment objectives of a decommissioning plan (DP) for a uranium mill tailings pile. The comments identify limitations in existing plans, characterize future data gathering and review needs and suggest design options to supplement existing plans to decommission the uranium facilities at Elliot Lake in a more effective and durable manner.
   2. The Panel Procedures for these Public Hearings provide for comments to "assist the panel in reaching informed and objective conclusions with regard to the proposals and as a basis for its recommendations". As the scope of "decommissioning", the Review Panel's August 1994 Final Guidelines, at p. 10) describe decommissioning in a very broad and permanent sense, including: "long-term stability of the tailings and all containment and control structure, control of radioactive and non-radioactive releases, control of seepage and other water releases, means of verifying the effectiveness of the decommissioning project once built," thus "long-term" is used in an open-ended, essentially permanent sense. Unfortunately, missing from the panel framework is a criteria for the panel or other authorities to formally or officially accept, reject or modify the Proponents decommissioning plans due to the "lack of legal force" for the Panel's conclusions or recommendations.
   3. The scale of the Elliot Lake waste deposits makes them a very important set of sites on a global level, and the approach taken will play an important role in the context of current intensive efforts in many countries to effectively dispose of their uranium mill tailings from past operations, even as new production sites are considered. The Elliot Lake Tailings Management Areas are among the largest uranium production waste sites in the world, surpassed in size only by sites in Southern Africa and Eastern Germany. The sites contain thousands of tons of hazardous radionuclides and heavy metals simply as a result of their sheer bulk, materials which present potential human health and ecological risk for hundreds to thousands of years, beyond the less than fifty year life of the production phase of the operations. While the radioactive material content of the TMAs is well recognized, the immense volume of heavy metals is less well understood. The Denison TMAs contain 15,000 - 30,000 tons of lead (assuming 250-500 ppm lead in the tailings in Denison EIS Table 3.1.17 and 60 tons for each one part per million for a 60,000,000 ton volume such as the Denison TMAs), 3000 tons of cobalt (at 50 ppm from Table 3.1.17), as well as 1500 tons of nickel, and more than 600 tons of chromium among other hazardous and radioactive constituents including 15,000 - 30,000 tons of thorium; roughly 65% of these same volumes will be found in the Rio Algom tailings.
   4. The Elliot Lake DPs should be assessed within the growing framework of existing global development of tailings decommissioning technologies and disposal policy models for comparison and the huge mass of permanently hazardous materials in a matrix with high acid drainage potential at the sites. With this international experience as a baseline, the Proponents' proposal has none of long-term physical barriers to resist natural climatic and biotic processes used in all other cases, and relies on active maintenance of open water (including operating a pumping station to provide a permanent replacement water cover) as well as a continuous monitoring and maintenance to prevent exposure or erosion of tailings or repair blocked spillway as a permanent active program.
   5. These comments show that, from the perspective of the need for a permanent containment system which minimizes active maintenance, the current decommissioning plans do not provide a durable, intrusion resistant cover system-using multiple engineered layers of physical and chemical appropriate materials. Neither do they provide sufficient post-closure care and maintenance sufficient to restore or reconstruct any of the major elements of decommissioned TMAs during the thousands to tens of thousands of years that the materials in the tailings will present a hazard to the region. The decommissioning plans do not provide a cover system with potential to effectively isolate the waste of concerns from the biosphere or containment sufficient to address the peak rain, wind, ice and biointrusion mechanisms, among other severe continuous or peak stresses on the sites.
   6. A very likely, very severe stress on the sites not considered in the EISs is glaciation. While exclusively a long-term concern, glaciation in the context of the next ice age, is likely to overcome any surface structure. If waste isolation is to be sought for such conditions, subsurface disposal below existing land surface to escape glacial movements would be required if containment beyond the 10,000 - 20,000 period is sought. Such is the case for other radioactive waste disposal sites with similar total radioactivity content as the Elliot Lake sites, but in a more compact form.
   7. A solution to this lack of effective long-term plans at the site is to separate the evaluation of decommissioning into phases which address 1) interim management and 2) long-term management conditions of a process with legal force. This approach would be a variation on the Proponents' response to comments about uncertainty in the long-term stability of the sites, adequacy of long-term monitoring and maintenance measures and comprehensive financial assurance. In those responses, the Proponents appear to separate a interim or "transition period" and a long-term or "post-transition period", each with a substantial effort to evaluate decommissioning plan performance, before final decisions are made on either design effectiveness of permanent land ownership and responsibility. In the context of these comments the effectiveness of the existing design would be evaluated prior to acceptance as effective whether private ownership is maintained or Crown authorities become responsible for the sites.
   8. The comments below provide a more detailed discussion of this recommendation, the basis for its as a reasonable response to the Proponents' plans, and technical performance and policy areas for the future review of the decommissioning plans at Elliot Lake.
2. The Lack of legal force to this review results in less rigorous and durable long-term plans and less thorough supporting documentation, than other international uranium mill tailings reviews, including those with substantial Canadian participation.
   1. The lack of thoroughness in design review, impact modeling and supporting documentation is very striking in comparison to other programs internationally and results in a less thorough investigation of the effectiveness and longevity of the Elliot Lake Decommissioning Plans than that currently being applied internationally. The lack of a clear process for enforceable decision-making on the adequacy of the plans and the acceptability of long-term monitoring, maintenance and financial assurance concepts results in the long-term issues being poorly evaluated and understood, even by Crown authorities potentially responsible for the long-term management of the sites, as shown in their comments.
   2. Around the world, dozens of uranium mill tailings disposal sites are being decommissioned, resulting in reduced environmental contamination and safety risk as well as an important increment of employment in the affected communities. Examples of fully decommissioned sites can be found in the USA, Spain, Sweden, and Australia and extensive site decommissioning and remediation efforts are underway in the Czech Republic, Germany and Hungary among many other countries. Each of these efforts involve a thorough identification of the performance level which a decommissioning project would need to obtain for acceptance with effective regulatory review by province-level and national-level regulatory scientists, within an enforceable legal framework. The Proponents ignore this extensive experience in their discussion of the "state of technology". The Review Panel and the public are not exposed to this experience, nor is it incorporated into the analysis of the proposed decommissioning plans. This failure to consider international experience and criteria is the direct reverse of the recommendations, cited below, made by several of Rio and Denison's consultants to German authorities for facilities of the age and size of the Elliot Lake facilities.
   3. The level of substantive review and governmental acceptance for these international facilities, even the level of detail indicated by Canadian consultants to other governments facing tailings decommission concerns is not cited. Several useful examples can be cited for criteria for review and evaluation of uranium mill tailings site characteristics and decommissioning plans, with quantitative as well as regulatory measures of performance, some of which had a substantial Canadian role. Examples, with supporting documents as identified appended to these comments, include:
      1. Germany - supported by "Review of Wismut Proposed Decommissioning Plans," Senes Consultants Limited, Golder Associates, and Brenk SystemPlannung, October 1991 - "General Issues and Comments" only included - (attached as Appendix A) which notes that:
         "There is a need for consistent, environmentally acceptable yet practical criteria and guidelines for decommissioning the sites. Criteria for radioactive constituents could be based on dose limits and site specific application, or design criteria such as those recommended ... Reasonable internationally-accepted guidelines and criteria could be used for early guidance."
      2. USA - supported by "Design Criteria and Standards for Uranium Mill Tailings Management in the USA", by Paul Robinson, August 1991, a review of the USA standards relying heavily on the original language of the US standards, presented at a Germany technical conference (attached as Appendix B). The EISs contain no references to the more than 20 completed uranium mill tailings decommissioning sites in the US, including the 33,000,00 ton Rio Algom tailings facility in New Mexico. This facility is mentioned only in passing in the September 28, 1995 Rio Algom letter on financial assurance (p. 5, "reclamation activities at .. its New Mexico site") but ignored in the discussion of "state of technology" in the EISs.
      3. Spain - supported by an abstract for "Remediation of Inactive Uranium Mining and Milling Sites in Spain" from the "European Union International Symposium on Remediation and Restoration of Radioactive-contaminated Sites in Europe," October 1993 (attached as Appendix C) which describes fully decommissioned mine and mill tailings facilities.
      4. International Atomic Energy Agency - IAEA has produced "reasonable internationally-accepted guidelines" for management of uranium mill tailings with major reports produced in 1989 and 1994, both of which included senior Canadian experts in their deliberations; no supporting documents are provided though they are readily available. The data base gathered in the IAEA reviews and the technology and guidelines identified in their reports are ignored in the EISs.
   4. The level of documentation and technical support necessary for full permitting is lacking from the Elliot Lake EISs, and Proponents' responses to comments provided through the Review Panel process, in large part because no specific legal requirements or responsibility is addressed in the Panel Guidelines, which themselves carry little identifiable legal weight. This lack of enforcement authority, inherent in the recognition that the "panel's conclusions and recommendations will not have legal force", which has resulted in a set of plans which provide a short-term fix to operational problems detected over the life of the Elliot Lake facilities but provide poorly developed and described long-term decommissioning plans.
   5. Administrative processes, at a provincial or national level, govern uranium mill tailings proceeding in each of the other examples. However, in the guidelines for Review Panel provide no clear delineation of the administrative process for insuring effective decommissioning for the Elliot Lake sites, a major weakness in the framework for evaluation of the DPs not found at sites of similar size or age in other countries. Examples of provincial and national review procedures appropriate for formal review of decommissioning plans can be found in the legal framework which constitute the USA, German, or Spanish programs as well as in the uranium mill tailings management reports of the International Atomic Energy Agency.
   6. This lack of legal force or a clear linkage to an enforceable decision has resulted in a set of decommissioning plans which are short-sighted and fail to address the specific mechanisms which can lead to long term dispersion of tailings in favor of a shallow, non-durable system almost completely constructed even before the panel has finished taking comments and issuing it conclusions and recommendations. These largely-completed repairs - The dam enhancements, spillways and treatment works - do improve in dramatic fashion on the short-term pollution control and remediation capabilities at the sites, in comparison with yellowcake production-era operations. In contrast, the proposals which have been received do not demonstrate that long-term performance objectives can or will be achieved, they rely on a thin layer of water to prevent intrusion into the tailings and dispersion of the contaminants in the wastes.
3. Consider the acceptance of the short-term effectiveness of the Decommissioning Plans and the long-term needs and uncertainties unresolved by this Review in a legal enforceable decision-making process.
   1. Not only are these plans being considered by a Panel without enforcement authority, the engineered systems being discussed at a fait accompli, they will be all but completed by the time the Review Panel issues its final statement and recommendations.
      The major portion engineered systems in the decommissioning plans - the site restoration and grading work, as well as dams and channels - which are the subject this Panel Review are not prospective plans, in that they maybe be built after review and evaluation, rather they are under construction and largely completed (see for example Rio Algom letter, September 28, 1995, p. 3, "...Rio has already spent $97M of the 106M estimated cost to implement the mine closures..."). These engineered improvements, the dam upgrades and diversion channels as well as the treatment works, can reasonably be relied on to be effective at reducing short-term risk, that is a 0 - 50 year period, of major release or failure.
   2. The dam and diversion improvements generally provide an engineered repair or replacement system which overlays and enhances the function of the informally designed set of impoundments as used during the yellowcake production phase of the Elliot Lake facilities. These improvements address tailings containment, slope stability and seepage release weaknesses of the TMAs which lead to the wide spread water quality damage of the earlier years when impoundment design and water treatment methods were not effectively applied.
   3. While the improvements are essential to the short-term containment and stability of the TMAs, the proposed approach is not well supported as a final treatment nor as a reliable an durable long-term approach. The long-term concerns are those that relate to tailings stability during a period of hundreds to thousands of years, particularly for the Provincial and Federal authorities which appear to be in line to acquire the sites and associated permanent monitoring and maintenance responsibility, if private responsibility is forgiven.
   4. The TMAs have already undergone substantial upgrades without review and approval for their long-term effectiveness prior to construction, upgrades which address problems of the last 30 years or so of operating experience. Accepting the construction as at least incremental improvement, the Decommissioning Plans - with modifications and conditions adopted by the panel or regulatory authorities - can accepted on an interim management basis as adequate to address control and containment problems during a short-term period. Such acceptance may be appropriate for a period of time up to the 30 year period since operations at the site began.
      Durable long-term management strategies can be developed, on-site monitoring and maintenance experience can be compiled, and land ownership and financial responsibilities can be formally established in a well-framed and thorough investigation established within a decision-making process. This process can be conducted during a period of several years, taking advantage of the interim as-built dams and treatment works as both control environmental upgrades and test sites for long-term geotechnical and natural resource management considerations. With this two phase process, the formal acceptance of Proponent Decommissioning Plans or alternative long-term monitoring and maintenance approaches by the Crown authorities most likely to be responsible for permanent monitoring and maintenance, would come only after a review process with legal force. And the evaluation sufficient to insure that site plans are rigorous enough to met long-term concerns should include additional data gathering and decision-making processes with legal weight, separate from a review process during which the stabilization and treatment measures under discussion were being built.
   5. The panel could recommended that the decommissioning works currently under construction could be considered the Interim Management Phase for the decommissioning of the Elliot Lake TMAs. Subsequent phases of decommissioning such as the long-term waste isolation and containment phase and long-term monitoring, maintenance and financial assurance program as the focus of future review, with a clear linkage between the review results and the legal framework for decision-making on long-term decommissioning effectiveness and responsibility.
   6. This process if implemented would have two highly beneficial results. First, it could recognize a clear value and benefit of the decommissioning work now under construction, during at least the next few generations, to prevent future contaminant release on the scale of those which occurred during the operational phase. Second, it would provide a well-structured framework for thorough consideration of long-term isolation and containment concerns, in a proceeding which has a clearer legal and administrative application and which provides a substantially fuller technical assessment of the long-term durability and effectiveness of those plans. This review of the long-term aspects of the decommissioning plans could include a substantially more extensive review than that provided in the EISs and comments and response for this Panel, while accepting the currently built works (as completed) for important short-term benefits.
   7. This two stage review would respond to substantial comments requesting extensive additional documentation and design modification from provincial and federal agencies and the public about the adequacy of the DPs to demonstrate the proposed plans are as effective as the Proponents assert. The scope of the long-term stability and effectiveness review could be drawn from the range of concerns about insufficient or unconvincing supporting data raised in the Ontario, AECB, Northwatch and other commentors as well as recommendations of the Review Panel. Important areas to evaluate more extensively or use more rigorous methods to address identified in these comments include an improved on-site characterization and analysis of the tailings and containment materials and well-calibrated three dimensional modeling or hydrogeologic and stability parameters of the systems as built.
   8. This two stage evaluation would allow operation of the current improvements while considering whether there is adequate foundation for a long-term containment. The current decommissioning plans at Denison and Rio Algom rely on a water cover as the sole barrier to both surface borne contaminant dispersion and tailings intrusion and a buttressed dam with no positive seepage cutoff barrier to stabilize the tailings and cover, as well as control seepage. These comments and those by others show that the methods in place are not well enough supported to be considered complete long-term decommissioning plans. In response, an additional review of the proposed designs, with a substantial improved field and analytic data support, appears to be necessary to provide a full demonstration of likely performance over the long-term. Development and assessment of alternative designs may be appropriate to improve the long-term stability of the sites upon their conveyance to Crown authorities for permanent monitoring and maintenance.
      In addition, these comments provide strong evidence to support the conclusion that these technologies would not meet long-term isolation and control standards for reasonably similar waste depositories in Canada or in other countries. A wide-ranging lack of confidence in the assurances provided in the EISs is also found wide throughout the comments submitted to the Review Panel, including those of the Ontario Joint Review Group. Federal agencies such as Environment Canada, Health Canada, CANMET, AECB, in addition to those provided by Northwatch and other public commentors.
   9. While the Proponents' responses generally indicate that comments were addressed elsewhere in the DP supporting documentation, or are referred as "well taken" (with no specific response to indicate what "well taken" implies), the Proponents appear to be maintaining their support for the plans discussed in the EISs. While the actual construction of most of the structures in the DPs has already been accomplished, and in a manner which addresses problems identified from the operational phase of the TMAs, no effective review and approval of the long-term aspects of the specific improvements appears to have been completed. Therefore, the decommissioning plans as installed can be considered to address past, current and short-term problems, but not yet acceptable from a long-term stability standpoint of the Crown authorities, as they potentially will be responsible, and liable, long-term control and containment at the TMAs.
   10. Deferral of acceptance of the DPs for their long-term adequacy allows for a detailed and well structured review while taking advantage of the existing upgrades as beneficial during a focused period of time when active maintenance and monitoring can reasonably be assured and site specific geochemical, climatic, and natural processes can be monitored. This site specific data is necessary to insure that Proponents' assumptions and models, as well as alternative cover strategies with more durable barriers between the tailings and the environment can evaluated. This improved database and operating experience is essential to verifying whether Proponent assumptions are valid and can be independently confirmed.
   11. This second phase is also needed to address the problems noted by commentors on the relatively shallow and conclusory discussion of long-term decommissioning concerns in the Proponents' EISs and responses to comments. This concern can addressed in the context of the water cover proposal as well as the containment structures, the impoundments. Several specific examples are provided to support this conclusion that the DPs are short-sighted and incomplete, addressing only a few decades of stability and containment and not addressing severe stresses for period up to or beyond a 1000 year period.
4. The water cover concept (and bare tailings concept at Stanrock) has not been presented in with sufficient supporting detail to address reasonably expected long-term intrusion and disruption processes.
   1. Water covers as an option for permanent reclamation and decommissioning of any mill tailings are rare outside Canada as no uranium mill tailings sites in any other setting has been fully decommissioned with a water cover. Water covers are typically considered in the context of the operating phase of a tailings facility where "water", or tailings liquids are maintained on the top of tailings disposal sites for radon and dust suppression from an environmental perspective, and for liquid storage and recycle from an operational perspective.
   2. The Proponents do not directly refer to any decommissioning criteria applicable to uranium mill sites in other nations or from international organizations such as International Atomic Energy Agency, nor do they cite technical literature which addresses water cover mechanics. See for example, Denison EIS, p. 4-7 where, within "State of Technology", the Proponents fail to identify any of the specific design components of any of the sites where uranium mill tailings inside or outside of Canada have been decommissioned whether in the US or other nations. Nor do they identify or consider the IAEA literature on uranium mill tailings which provide reviews of tailings management policy from a international working committee, which included senior Canadian scientists and engineers.
   3. The proposed covers at Denison and Rio Algom rely solely on wet covers less than one meter thick placed directly on top of the tailings, acting as both a physical and chemical barrier. The effectiveness of these covers are not addressed in a scientific manner relying on experimental and literature support. Quite the contrary, their effectiveness is assumed as full, complete and permanent and not open to investigation. The Denison EIS for example indicates that:
      • "water cover provides an effective barrier to intrusion by man" (p. 5-7);
      • "Scientific studies have shown that these acid forming reactions can effectively be controlled so that acid production is essentially stopped"; and
      • "A water pond over reactive uranium mill tailings can prevent further acid production...(p. 5-1)".
   4. These assertions can be addressed in the context of both the EISs and subsequent documents.
      1. The concept of complete prevention of acid drainage for water covered setting is specifically not supported, though it is the cornerstone of the Proponents' approach. No research is presented to demonstrate the relative rates of acid generation for wet and dry covered tailings. Nor is research presented regarding the scale of monitoring, maintenance and repair of a continuous water cover in the face of water and wind erosion, freeze and thaw cycles, ice formation, or bio-intrusion, such as animal burrowing or lodge-building and root intrusion into tailings.
      2. Research shows that acid drainage continues under water covers and is not fully prevented. The lack of reference material to support the complete prevention of acid drainage in the EISs is very striking, but easily remedied. The Proponents cite several articles from the Proceedings of the International Land Reclamation and Third International Conference on Abatement of Acidic Drainage, Pittsburgh, PA, April 24-29, 1994, but not an article by Kim Lapakko, principal engineer with the Minnesota Department of Natural Resources, which presents measured acid production rates for water covered tailings and non-water covered tailings (and is attached as Appendix D). In this study, the acidity of the tailings in water-covered samples was shown to increase significantly (pH dropped from 4.5 to 3.5). Sulfur release rates for the water covered tailings were 10-20% of the acid production rates of control acid production rates and rising over a two year period.
         Lapakko is considerably more cautious in his conclusions than the Proponents, he states that "although the rate of oxidation may be inhibited, sulfide minerals can oxidize in a subaqueous environment....empirical determination of sulfide mineral oxidation rates for specific mine waste in the laboratory, in conjunction with the existing knowledge on the diffusion of oxygen, allows calculation of pyrite oxidation rates and the resultant water quality."
      3. The Proponents assume just the opposite of this research-based conclusion. They conclude that acid generation is "essentially stopped" and a process they "can prevent", but offer no long-term field data at the sites to support such a complete exclusion of the possibility of acid generation. Lapakko's data demonstrates continuous acid production at a lower, but certainly significant rates, and asserts that a intensive program analyzing the specific materials is needed to reach a conclusion on acid generation at any site. A second article by Lapakko from the 1994 Conference not noted by the Proponents, included as Appendix E, provides a basis for neutralization and acid generation assessment related to the onset of acid conditions, near pH 6.0, rather than in the pH 3.0-4.0 range when acid conditions well advanced, Methods identified by Lapakko in Appendix E should be included in future long-term decommissioning plan acceptance reviews for Elliot Lake facilities.
      4. The Proponents have not presented a quantitative basis for their conclusion that their DP will assure that acid drainage can be prevented. And certainly they have not presented "empirical determination of sulfide mineral oxidation rates for [the] specific mine waste [under discussion] in the laboratory, in conjunction with the existing knowledge on the diffusion of oxygen, [to] allow calculation of pyrite oxidation rates and the resultant water quality." The Proponents have not presented data on the actual acid generation properties of their tailings wastes under projected environmental conditions, nor have they presented acid generation data from static or kinetic test of their materials, nor have they presented a calibrated three-dimensional model of, and other geochemically driven migration processes for, the TMAs. Each of these types of studies are basic to an authoritative and well-substantiated conclusion of potential acid drainage rates and other contaminant movement dynamics.
      5. Work at the level of detail indicated in the Lapakko articles is necessary to address the acid generation aspects of the decommissioning plans at Elliot Lake. Such work is necessary to insure that significantly lower acid production rates than 10-20% of the rate for uncovered tailings can be achieved, demonstrated by monitoring data, and maintained under low and high environmental stress conditions, over hundreds to thousands of years. Such work is also needed to insure that acid generation is detected as early as possible in order to insure that a full range of pollution prevention opportunities are available, not just remediation after extensive acid generation has occurred.
   5. The Proponents' presentations have been developed without specific acid generation evaluation criteria, limiting their ability to focus on clearly articulated data gathering and analysis methods. More specific criteria for consideration of acid generation potential and its prevention should be articulated for future review of the long-term aspect of the TMA plans. A useful example of data needs and methods appropriate for a detailed quantitative assessment of potential acid production rates from a Canadian source is the "Prediction of Acid Rock Drainage" portion of the "Province of British Columbia Mine Development Assessment Process Summary of Outstanding Issues and Terms of Reference ..." for the Windy Craggy Project issued in July 1992 (attached as Appendix F). This approach, recommended after presentation of the operator's technical plan and supporting documents not completely different than the Elliot Lake situation, specifically outlines a combination of static and kinetic tests of project wastes to develop accurate models and prevention methods.
   6. While the Windy Craggy document addresses a prospective mine, rather than an existing tailings management area, British Columbia's recognition of the need for specific field tests as well as static and kinetic lab tests of long duration to support a conclusion about projected of acid drainage, rather than a conclusion by analogy to research at other sites is very appropriate in the context of the Elliot Lake sites. This need for a full site-specific data base for acid generation analysis at each site to provide a workable model is supported by both the Lapakko articles and the British Columbia material.
   7. This recognition of the need by the Province of British Columbia's regulatory authority, for a high-quality site-specific data base for acid generation analysis is also notable as so much of the Canadian research on acid drainage, notably MEND program activities, has been generated by the various segments of the technical community in that Province. The conclusion being that even where a substantial amount of knowledge has been developed on acid drainage at a range of sites, a detailed site specific program is needed to specifically characterize and address acid drainage potential. Such a program is needed at the Elliot Lake sites before decommissioning plans are considered final or fully implemented.

 

5. Reasonably anticipated severe climatic conditions as well as biotic processes for tailings release due to physical intrusion and disruption are not addressed.
   1. Water covers are not effective physical barriers to climatic and biological intrusion without constant active maintenance. The Proponents assert that a water cover is an effective permanent barrier to intrusion at the Denison and Rio Algom sites; see for example the Denison EIS which indicates:
      • "that for the wet cover options, erosion factors from wind and water are greatly reduced", (p. 4-35); and
      • "experience with flooding to prevent acid production is well demonstrated", (p. 4-38).
   2. In spite of these assurances, concern over the durability of the water cover has been raised by many commentors, specifically for drought or low water conditions, which have led to Proponent commitments to insure that pumping additional water from Quirke Lake will be maintained as a permanent option to replace any potential loss of water cover. In addition to risks of tailings release during low flow conditions identified by other commentors, many other natural processes can lead to widespread penetration or disruption of the tailings surface and distribution of tailing solids.
      These processes are uniquely important at the Elliot Lake sites since they are proposed for decommissioning with no barrier to contain and isolate the tailings from physical erosion and biointrusion. Water may delay acid generation and keep the tailings saturated but it is not a potential barrier to root penetration and other biotic intrusions, as well as climatic factors such as high wind, wave action, ice, and freeze and thaw effects, which can lead to penetration and loss of the water cover without continuous and active maintenance, and extensive repair or reconstruction to address periodic severe events.
   3. Biointrusion, with its associated release pathways due to bioaccumulation and contaminant uptake, in addition to deep root penetration into tailings with associated oxygen diffusion and potential acid generation risk well below the water surface, are major contaminant transfer mechanisms which are all but ignored by the EISs. Natural revegetation processes are already occurring at the TMA sites however no database or analysis is discussed to address the contaminant transport and acid generation conditions for the TMAs for the long-term period of concern whether extensive wetlands and forests develop at the sites or whether active maintenance is used to maintain open water for tailings cover.
      A review of these concerns, "Biotic and Abiotic Processes" by Prof. Thomas Hakonson and others from "Deserts as Dumps?", University of New Mexico Press, 1992 is included (Attached as Appendix G) to provide an overview generally lacking in the EISs.
   4. The shortcomings of the EISs in terms of quality of information regarding distribution and contaminant transfer for biota, plants, animals and occurrence of specific indicator species at the sites, as well as the characterization of the wetlands and other ecological communities integral to the Decommissioning Plans are well identified by Environment Canada and other commentors.
   5. Comments regarding lack of active and effective long-term monitoring and maintenance to address a biotic process of concern can be found in the CANMET comments. Those comments note that, on p. 13, "A monthly/seasonal inspection of engineered structures would not appear to be frequent enough given the complexity of the hydraulic systems and the need to protect against beaver blockage of spillways. This applies to both the transition phase and to the long-term." This concern appears to indicate a need for relatively constant surveillance at the sites to assure that no disruption of the water cover is allowed (to the complex hydraulic systems which maintain a constant water cover) for the long-term, the period up to and beyond 1000 years. This degree of active surveillance and repair capability is not considered in the low intensity long-term approach of the Proponents.
      As an aside, another condition requiring permanent and daily monitoring is found in the comment by CANMET regarding vandalism. While an unfortunate problem, the sites, particularly the impoundments and spillways are very accessible by paved roads and are vulnerable to "hit and run" vandalism. CANMET recommendations for "daily inspections ... to prevent intrusion" also would apply to the long-term, up to or beyond a 1000 year period.
   6. Site-specific bio-intrusion and contaminant transport related to natural succession at the sites are not considered in appropriate detail.
      1. As indicated above and in the EISs, the "water covered" TMAs will be active ecological systems which will provide many opportunities for disturbance and penetration of the water cover, in addition to low water conditions. A major source of concern is the biological community which will establish itself around and within the tailings. This concern includes establishment of plant communities with bio-transport capabilities with root depths well into the tailings, as well as plant-eating, burrowing, and lodge-building animals, and the microbiological and invertebrate biota in soils. The effects of these processes on the TMAs is largely dismissed with a cursory discussion such as the Denison EIS, at p. 5-39, which concludes that "vegetation is not an integral component of the design, however the establishment of healthy aquatic vegetation could improve the overall effectiveness of the project....At Denison, large stands of cattails are invading shallow water and extensive cattail stands will be present over the next several years... In TMA-2, the water saturated rare-earths area has developed an extensive cover of natural vegetation".
      2. Though the Proponents appear to anticipate well-vegetated sites over the long-term, they provide no data on the uptake of contaminants by this current or anticipated vegetation, nor what the future biological community will be composed of, how it will provide a pathway for contaminant uptake, and projected plant consumption rates by local wildlife and fish. Vegetation is only considered in the context of "overall effectiveness of the project" and not addressed as a source of contaminant uptake and transport in any quantitative matter. The roots of that vegetation will provide for effective contaminant migration as the plant roots will rely on the tailings for minerals and nutrients to convert into plant tissue, which will either be consumed directly or decay on the water or soil surface and be available for water or wind-borne transport.
         With only a water cover and no physical barrier between the tailings and the water, such as a combination of clay, rock or soil barriers as at all USA sites as well as Spanish and other European sites, an extensive root network penetrating into the tailings themselves is assured at each site. The Proponents have left the long-term implication of their water cover concept very unclear and provided no organized evaluation of contaminant uptake parameters, either for comparative sites or the specific TMAs under discussion. Similarly, no habitat or species management criteria, data gathering program or monitoring system to assess the dynamic or limnologic (lake ecology) processes over short or long-term cycles is proposed for use in acceptance, monitoring and maintenance evaluations at the TMAs.
      3. Root penetration is an important process which can provide for contaminant migration in several key ways. These include transfer of contaminants from the tailings through the roots into plant tissue which is consumed or which decays on the water or soil surface. With only water and no physical barrier, such as a combination of clay, rock or soil barriers as at all USA sites as well as Spanish and other European sites, an extensive root network penetrating into the tailings themselves is assured at each site. No organized planting or species selection criteria are proposed and no analysis of bioaccumulation dynamics at the sites is offered.
      4. The root zone is also an active environment for microbiological activity and oxygen diffusion. Microbiological activities are a well recognized component of the chemical dynamics which can initiate or control acid generation. Little is said about this important process, though the literature on bioaccumulation and bioremediation is rapidly growing (see for example, Proceedings of 1993 International Conference on Pollution Prevention in Mining and Mineral Processing, Colorado School of Mines for effective discussions from Japan and Montana and Colorado in the USA).
         1. Root uptake of chemicals in the tailings will occur as plants invade the shores or caps of the TMAs. With no alternative soil media, or barrier to reduce root intrusion, such as clays and rip-rap/dump rock, extensive uptake is assured. This process is likely to be a major form of release of contaminants from the tailings over the long-term, thousands of years, yet is ignored in the EISs. Such a evaluation should be critical to acceptance of a long-term decommissioning strategy.
         2. Roots also provide for opportunities for oxygen diffusion through a soil zone through biochemical processes in living plants as well as pores resulting from decayed roots. Such processes can occur very deep in a soil horizon depending on the available combination of soil, water and plant morphology rooting depth. While the long-term appearance of the TMAs is unclear, a future where 100 - 200 years from now the TMAs are covered with extensive vegetation, with a complex community of cattails and other wetland species and mature trees in lakeside areas and on islands that have formed within is not unreasonable. These plants will rely heavily on tailings for nutrients and transfer heavy metals and radionuclides from the tailings to the surface. Mature trees, including willow and local pine can be expected to root particularly deep into the tailings, as no alternative root zone or barrier is provided, and the tailings are projected to be saturated.
      5. This active root zone, as a direct interface between plants and tailings, is also a host for active animal and microbiological life; communities which would enter the wetlands and forested portions of the decommissioned area. Animals living in, visiting, or feeding on animals from the sites will have a high potential to accumulate metals and radionuclides derived from the TMA sites. These exposure pathways also provides a direct risk of exposure to humans who may fish, hunt, or gather foods near the sites.
   7. Root penetration as a means of oxygen diffusion
      1. Deep root penetration and its affects on oxygen availability below the surface is a concern at sites with acid generation potential. Deep rooting trees, such as willows and pines, as well as locally abundant cattails, shrubs, grasses and other plants are certain to utilize tailings as a primary root zone, as no soil zone, or barrier layers such as rip-rap and clay layers are anticipated. The effects of this extensive root network on tailings contaminant transport chemistry is not addressed well. The Proponents' conclusions rely on studies of very short term aspects of water covers, with only a superficial consideration of the long-term ecosystem being created at the sites. Similarly the Proponents do not address the potential impacts of root/soil interaction on oxygen availability at depth, a major geochemical concern for sites with acid generation potential.
      2. Certainly a substantial and impressive body of literature has been developed by Canadian researchers on groundwater and acid drainage aspects of mine waste reclamation. Some of this data includes research on uranium mill tailings remediation which indicates that a seepage front which develops within a tailings pile may stabilize within the tailings, with a leached zone above the front as a barrier to further infiltration and contaminant migration, resulting in large part from limitations on available oxygen within the tailings.
      3. This concept is well developed in "Acid Generation and Contaminant Transport in Decommissioned Sulfide-Bearing Mine-Tailings Impoundments" a paper by D. Blowes from University of Waterloo at a 1995 Uranium Mining and Hydrogeology Conference in Freiberg, Saxony, Germany (Attached as Appendix H). Dr. Blowes provides an overview of the relationship of oxygen diffusion and bacteria activities in acid generation potential. However no information is presented on long-term acid generation in tailings where deep rooting vegetation provides pathways for oxygen diffusion though an extensive tailings depth. Such concerns are important for long-term tailings stabilization questions such as those before the Panel.
      4. When asked about follow-up investigations at the sites discussed, Dr. Blowes indicated that such studies were anticipated but not complete and when asked how the penetration of roots into the tailings might affect the low oxygen-zone where contaminant movement had slowed, he indicated that he also considered biological sources of oxygen such as root transfer-derived oxygen to be a potentially significant source of oxygen which would be delivered at depth into a tailings mass. In Dr. Blowes work and others, the research generally addresses an unvegetated waste pile with little or no root penetration into the tailings, These conditions contrast sharply to those anticipated at the Elliot Lake sites. Rio Algom and Denison consider eventual establishment of wetland and bog conditions, including shrubs, trees and other plants likely, leading to large-scale intrusion of a deep and extensive root network, and associated contaminant dispersion. This impact should be addressed thoroughly before acceptance of a wet cover without and underlying multi-layered engineered cap, or a bare tailings option, is considered for long-term decommissioning.
   8. Climatic process for tailings intrusion and release.
      1. The EISs do a particularly poor job of addressing the effects of severe climatic conditions on the water covers. This may be because the water provides only a superficial barrier to wind and wave erosion and become part of the problem when it becomes ice on an annual basis. CANMET also recognizes this concern when it comments at p. 3, "In certain conditions, seasonal ice may form dams or ice-push features capable of eroding containment structures or blocking spillways". Ice formation as well as freeze and thaw processes in the tailings and impoundments are very important processes to address thoroughly at the Elliot Lake sites because of the long and intense cold season in the region and associated deep frost conditions, likely to be well below the thickness of the proposed water cover. The effects of ice formation and movement on the TMAs over the long-term, and improved covers beyond the water cover, or a narrow berm to protect the upstream face of the impoundments, should be fully addressed before final determinations are made on the effectiveness of the water cover.
      2. The lack of on-site climatic data at the TMA sites prevents the Proponents from presenting a site-specific picture of local climatic conditions. This very unfortunate state of affairs, even after a 30-year operating history at the sites, leaves the relative severity of local weather conditions an unknown quantity.
         This gap can be remedied during the Interim Management Phase with implementation of an effective meteorological data gathering program added to the site specific data gathering regarding acid generation dynamics, impoundment stability and biological monitoring necessary for future reviews prior to final decision-making on the Elliot Lake sites.
      3. The stability of the impoundments at the Elliot Lake sites with projected water covers, in the face of wave action and erosion due to wave borne debris, such as tree trunks, and ice push has not been addressed in a thorough or quantitative manner. As a result many commentors have questioned whether the impoundments and spillways, as well as the protective berms protecting those spill ways can considered "erosion resistant in the long-term", as CANMET did, at their p. 24.
      4. The fundamental stability of the protective berm at Denison is questionable as well, as CANMET notes in its comments at p. 23, "Can a tailings berm be placed on poorly consolidated slimes near a dam face, and if so will it be physically stable?" The lack of an effective discussion of the hydrology and stability of the reworked tailings within the dams and the geotechnical implications of saturated tailings on the upstream face of a permanent impoundment, should be addressed in a subsequent review with legal force, before the decommissioning works subject to this Review Panel are considered acceptable for anything more than a short-term period.
   9. Failure to consider reasonable alternatives with lower monitoring and maintenance requirements and significantly improved intrusion resistance.
      1. Root/soil interaction and other biointrusion are major concerns for the TMAs since no barrier between roots and the tailings is proposed. The failure to provide an physical barrier between the tailings and water, solids, or other material leaves the tailings vulnerable to extensive penetration of the tailings by plant roots and animals as well as disturbance by freeze and thaw and ice formation and break up impacts. These severe stresses to long-term integrity of the sites are generally ignored or glossed over by the Proponents.
      2. The EIS did not thoroughly consider, either conceptually or quantitatively, the need for durable barriers to reduce physical and biological intrusion, even as a supplement to the chemical barrier functions of the water covers.
         The need for a combination of both physical and chemical barrier is well recognized at the wide range of decommissioned uranium facilities and in the decommissioning policies being implemented around the world, including African, European and North American settings. The typical physical barriers are a combination of compacted layers of sand, clay, cobbles and sized rip-rap, designed and installed to provide an engineered level of hydraulic, chemical or erosion-related performance. Such a multi-layer cover, whether below a water cover or not was not addressed in the EIS as either a site option or a common element in the "state of the technology". Such a multi-layer cover, if well designed and installed, would address the long-term intrusion and disturbance stresses raised in these and other comments, and reduce long-term maintenance and repair needs.
      3. The Proponents dismiss the concept of a dry cover with a very cursory review and offer no consideration of the multi-layer covers in place at USA and Spanish sites or the international experience compiled, with Canadian participation by IAEA uranium mill tailings management reports. The EISs fail to discuss the widespread international acceptance of multi-layer durable covers at tailings disposal sites at any detailed level and dismiss fail to identify reasonably available materials for use in such covers. The "state of technology" discussions fail to address the multi-layer cover approach either conceptually or quantitatively, even failing to describe the cost and installation of such a cover at Rio Algom's facility in New Mexico, the largest uranium mill tailings reclamation project to date in North America.
      4. Clay layers, when well engineered and properly installed, can be provide both a physical and chemical barrier to vertical migration of contaminants and have been applied in the at numerous sites in combination with protective soil and rock cap material. CANMET, in its comments at p. 3 notes that "... in the Serpent River watershed, clay deposits are extensive." correcting the Denison EIS impression at p. 3-3 that clayey deposits are not available for use as cover material because they are depleted at simply at Elliot Lake. Since, sufficient clay for cap construction appears to be available (contrary to the Proponent's assertion) alternative cover concepts using multiple engineered layers including clay layers and large diameter (0.25 - 0.5 meter diameter) rip-rap caps addressed in any future legally binding reviews.
      5. Denison and Rio Algom recognize that a thick cover is worth considering but dismiss it, see the Denison EIS, at p. 4-15, where they indicated that "large volumes of barrow material would be required to construct a 2 meter soil cover ... the significant quantities of borrow material required would result in the development of large borrow areas with consequent deforestation and disruption of natural drainage and wildlife, etc. it is estimated that approximately 20 years would be required to construct the soil cover."
      6. Denison is relying on protection of pristine environment within an area where they argue natural revegetation is a beneficial process, to prevent the consideration of a cap over a large volume waste deposit with substantial concentrations of hazardous materials. This disingenuous discussion should not be considered as the final word on the need for a cap, since the hard cap would provide critically needed long-term isolation benefits and any surface disturbance could be mitigated using well developed reclamation techniques.
         What limited discussion is found of alternative technologies, from other decommissioning experience or as applied to the TMAs, is not supported by quantitative methods or site-based data. The shallow nature and substance of these poorly cited portions of the EISs leaving the experience of the Proponents and their contractors at other sites, and the programs implemented in other countries outside the Review Panel discussion.
      7. Important cases of mill tailings decommissioning with respect to cover design and construction can be found in New Mexico, which like Ontario hosted several generations of large uranium production facilities. The use of local rock and soil as uranium mill tailings capping material has been well demonstrated at the Homestake and Arco uranium mill tailing piles in New Mexico near Rio Algom' decommissioning project at the former "Kerr-McGee" facility. These three facilities are the largest uranium mill tailings piles in the USA, each in the 30,000,000 ton range.
      8. The operating and decommissioning experience at these facilities is directly relevant to the Elliot Lake facilities since they are so comparable in scale, nature of the materials, relative content of hazardous constituents and need to provide long-term containment without active maintenance and repair. Comparison to this real design and construction experience would prevent the Proponents from superficial assertions such as that soil covers require "20 years to construct". In fact, Homestake and Arco have completed their soil and rip-rap caps this summer, less than five years after final permission of regulatory agencies. The two piles in combination contain as much tailings as the Denison TMAs, demonstrating how outlandish the 20 years figure is compared to the real world.
      9. The Proponents' failure to recognize the need and value of durable multi-layer covers from a long-term tailings containment perspective, as well as in terms of minimizing long-term monitoring and particularly maintenance liabilities, results in a water cover strategy which amenable to short-term monitoring and maintenance, but not rigorous enough to address long-term intrusion and sever climatic events, outside the consideration of seismic stability raised by others.
   10. Seepage modeling and containment are not sufficient for consideration of long-term acceptance.
       1. Seepage management concerns have been raised by many other comments, however several additional points appear to be important to identify. Denison EIS Figure 5.3.2 shows a cross section of Dam 10 without indicating if or where subsurface seepage barriers, such as a cutoff wall or grout curtain, beneath the dam into or below the granular overburden upon which the dam is built. The Denison Appendix C, at C-1-34 notes that seepage effects at the Denison sites has been detected in monitoring wells 40 meters and 57 meters deep, as Denison's consultants note, "this suggests that seepage from TMA 1 has migrated downward into the deeper bedrock (i.e >30 meters depth) from the basin toward Quirke Lake. However no effort is indicated to cut-off or collect this seepage flowing through fracture below the impoundment."
       2. This potential for subsurface flow at the dams which surround the Elliot Lake TMAs has been very poorly addressed in the EIS. Detailed site-specific data and dynamic testing results necessary to address fracture flow dynamics, and hydraulics within the tailings and the impoundment necessary to model seepage flow are similarly missing from the EISs.
       3. The flow lines - "equipotential contours" - represented in the Denison EIS on Figure 5.3.6 are not supported by a transparent (that is readily apparent) data base or well-calibrated model within the EISs. While flow from the tailings to and through the dam is projected for 1993 (Figure 5.32.4), the dam is represented as some becoming impervious to infiltration in Figure 5.3.6.
       4. As Figure 5.3.6 represents, the Denison approach as well as it close analog, Rio Algom, rely on a very simplistic model of containment, with no seepage projected and a perfectly functioning seepage berm, (though CANMET is concerned that the berm may not even be stable even if it is possible to put it in place, much less effective due to unconsolidated foundation conditions for the berm).
          To remedy this import data gap, substantially more detailed field data, utilized in a well-calibrated model subject to independent verification, in a process with legal force to decisions made, is needed to address long-term seepage flow below the dams, as well as the adequacy of any monitoring and maintenance or subsurface repair requirements if fracture flow seepage is detected by either short- or long-term monitoring.
       5. Dam 10, among other improvements, is a vast improvement on the operational conditions prior to the current upgrade. However repair of past defects prior to review and acceptance should not be substituted for a comprehensive review of long-term consideration in a legally binding framework. A second phase, legally binding, review of the Elliot Lake facilities is critical to public and Crown authority confidence and acceptance of a long-term low maintenance decommissioning plan is to be demonstrated effectively.

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About the Author — Wm. Paul Robinson is Research Director of Southwest Research and Information Center where be has been an environmental analyst specializing in solid waste and mine waste management for 20 years. He is Adjunct Professor at the University of New Mexico where he teaches "Environmental Evaluation Methods" in the Community and Regional Planning Program. The professional project for his master's degree was "Planning for Reclamation of Uranium Waste Sites in Eastern Germany". He has had technical papers on mine waste management including uranium production sites, accepted for publication in Germany, Canada and the USA as well as by the European Union Nuclear Science and Technology Directorate. He has appeared as a expert witness in licensing proceedings and review panels in British Columbia, New Mexico, Colorado, Nebraska among others. A full resume is enclosed with these comments as Appendix I.

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Selected References:

"Review of Wismut Proposed Decommissioning Plans," Senes Consultants Limited, Golder Associates, and Brenk SystemPlannung, October 1991

"Remediation of Inactive Uranium Mining and Milling Sites in Spain" from the "European Union International Symposium on Remediation and Restoration of Radioactive-contaminated Sites in Europe," October 1993

"Prediction of Acid Rock Drainage" portion of the "Province of British Columbia Mine Development Assessment Process Summary of Outstanding Issues and Terms of Reference ..." for the Windy Craggy Project issued in July 1992

"Biotic and Abiotic Processes" by Prof. Thomas Hakonson and others from "Deserts as Dumps?", University of New Mexico Press, 1992

"Acid Generation and Contaminant Transport in Decommissioned Sulfide-Bearing Mine-Tailings Impoundments" a paper by D. Blowes from University of Waterloo at a 1995 Uranium Mining and Hydrogeology Conference in Freiberg, Saxony, Germany