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Uranium & milling: Assessing issues of environmental restoration

The IAEA is providing assistance toward solving problems in Central and Eastern Europe and the Newly Independent States

by I ollowing political changes in Central and ures needed to satisfy society's higher expecta- Giorgio Gnugnoli, Eastern Europe (CEE) and the emergence of tions in the area of environmental and radiologi- Michele Laraia, Newly Independent States (NIS) from the former cal protection made production of un- and Peter Stegnar , a great deal has been learned about profitable for many low-grade mines. Moreover, the environmental situation in these countries. this economic consideration has further compli- Extensive industrialization and exhaustion of the cated implementation of site restoration. region's natural resources had been pursued to Although some of these mines/mills will accomplish quota-based productivity goals. In probably reopen when demand and prices in- many areas, the preservation and protection of crease, many will be shut down permanently and the environment were often neglected in the need to be decommissioned/closed out. As this process. situation has evolved in a relatively short period The political changes brought forward a frag- of time, limited resources were put into reme- mentary disclosure of radioactively contami- diating or even securing contaminated areas in nated sites. They also created conditions in CEE countries and the NIS. which these countries became receptive to co- The following factors contribute to an in- operation from a range of countries from which creased risk of radioactive contamination: they previously had been isolated. • long operational periods contribute to Although the need for environmental restora- greater risk of contamination; tion is not limited to the CEE and MS regions, a • higher ore grade increases radiation dose few distinctive features may raise additional com- rates from the residues; plications. For example, if the uranium production • natural climatic conditions (e.g., rain, wind) facilities are found to require some form of reme- significantly enhance dispersal and contamina- dial action, the size and location of the CEE and tion; and NIS production centres pose potential complica- • countries with limited resources can only tions in the restoration work. Unlike some coun- allocate marginal resources to environmental tries in which mineral development occurred in restoration. remote areas (e.g., the ) or resulted in Unfortunately, most of the CEE countries relatively small volumes of waste, the CEE coun- and NIS "qualify" under these factors. This arti- tries and NIS face greater logistical complications cle briefly describes some of the typical prob- for two obvious reasons. Firstly, the volumes of the lems in planning and implementing environ- accumulated are far too high to mental restoration projects in these countries. be removed at a reasonable cost. Secondly, safer alternative disposal sites are either not available or else are impractical. Basic conditions and problems During the 1980s and early 1990s, many older uranium mines were closed because of a Although some political, economic, and in- decrease in the demand for uranium and an in- frastructural conditions are common to many crease in the overall supply. The resulting low countries in the CEE and NIS regions, large prices and the cost of providing the extra meas- variations exist. In general, three categories of basic environmental restoration situations can be Mr. Gnugnoli and Mr. Stegnar are staff members in the IAEA identified: Department of Nuclear Safety and Mr. Laraia is a staff • countries with limited development of the member in the Department of Nuclear Energy. uranium having small amounts of min-

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ing/milling waste and few contaminated sites (e.g., Poland); • countries with a more developed uranium industry having several mines/mills and moder- ately impacted resources (e.g., Romania); and • countries with a fully developed uranium industry having many mines/mills and severely impacted resources (e.g., the ). Typical problems associated with past prac- tices in CEE and NIS include release; contamination; proximity of con- tamination to populations; lack of resources to conduct restoration; availability of disposal loca- tions/alternatives; absence of regulations or a regulatory infrastructure for restoration; misuse or removal of for use in construction; absence of responsible operators; and large in- ventories and areal dispersion. In some cases, groundwater contamination is such a severe issue that major sources of drink- ing water are threatened by radiological and chemical contamination. Another typical situ- ation in CEE countries is the proximity of ura- nium production sites to population centres. This proximity has, on occasion, led to the use of some of the waste rock and tailings materials for building purposes. Such structures are constant sources of indoor radon, one of the most signifi- cant radioactive hazards.

Above: The Pecs uranium mining and milling site in Hungary shows "heap " piles and waste rock. /Credit: Mecsekore Mining, Hungary) Right: A contaminated channel crossing the village of Yana, near the Buhovo mining and milling site in Bulgaria.

IAEA BULLETIN, 2/1996 23 FEATURES

Special problems of environmental that these countries will go different ways, be- restoration in the region cause of the dissimilarities in the nature of their present economic and political objectives. This Site specifications. The siting and charac- is not beneficial in light of the overall goal of terization of radioactively contaminated sites in efficient use of resources in environmental resto- CEE countries is probably the most difficult ration. Geographical proximity, similar political problem in relation to environmental restoration structure, and the same types of waste dictate projects. The available data is not only incom- co-operation and the use of similar technology plete but also somewhat questionable. A precon- and experience. dition for environmental restoration projects Public attitudes. Another problem with envi- must be the availability of sources of data perti- ronmental restoration projects is the governmental, nent to the specific radioactively contaminated scientific and public view of the problem of radio- sites; otherwise the efforts and resources put into active waste. Since radioactively contaminated the process are useless. substances have been commonly used in these re- Organizational problems associated with gions for nearly 50 years, in conjunction with out- the political changes. In many CEE countries dated practices in the handling of the material, the and the NIS, the old regulatory framework is public has had little recourse but to accept the being changed to reflect newly independent or presence of radioactive waste around them. In radically altered political structures. Such frame- many instances, the public did not even know that works, including the development of new laws these substances were in such close proximity to and regulations, are planned or are just coming their homes. This situation appears to be changing, into existence. In some countries, existing laws as people in these countries come to understand will necessarily be adapted to changed political the hazards associated with such waste. situations. There will be a period of transition, as such changes occur and ambiguities in new re- sponsibilities are resolved. This situation is Solutions for contaminated sites likely to complicate decision-making in environ- mental restoration. In many ways, the strategy used to deal with The funding of environmental restoration contamination and releases from operational work. A number of outside agencies, such as the mining and milling facilities is similar to that World Bank and European Bank for Reconstruc- used in past practices. For example, erosion- tion and Development, as well as individual driven, off-site contamination is characterized countries and groups of countries such as the and, where practical, excavated and returned to European Union, are offering support for envi- the original site. Certain practices and strategies, ronmental restoration. However, there can be a if put into place during the operational period, lack of co-ordination and, therefore, duplication can result in significantly reduced restoration among these projects that could result in the efforts at the time of closeout. inefficient use of available funds. Moreover, ef- Current strategies for mining and milling. fective allocation and distribution of financial Current operations employ certain practices, in resources within countries may also prove to be conjunction with an overall isolation and burial difficult. strategy, which provide a safer and more effec- Available infrastructures for managing the tive approach to disposal. These waste manage- wastes and residues from remediation pro- ment practices include spraying ore piles and grammes. To effectively manage the residues tailings beaches with water and/or chemical sta- and wastes from the cleanup programmes, coun- bilizers; use of baghouses at the crushing and tries need infrastructures/fa- blending areas; combined use of wet scrubbers cilities to process, store, and safely dispose of with baghouses at U3O8 drying and packaging any resulting radioactive wastes from restora- areas; grouting mine cavem walls; adding neu- tion. In many CEE countries and the NIS, the tralizing agents to tailings liquids, and ventila- stages of the were regionally tion of underground mines. co-ordinated. In most countries only parts of this Tailings impoundment and waste rock piles. infrastructure remain. Without having practical Current waste management strategies at conven- access to radioactive waste disposal facilities, tional mines and mills consist of burial, backfill- cleanup efforts may be limited. ing mines, and deep/shallow lake disposal. Increasing differences among the CEE These types of disposal strategies can be greatly countries and NIS. Large co-ordinated projects enhanced by additional features for environ- are likely to be more cost efficient and beneficial mental protection: for these regions than having separate national • backfilling mines with soil/rock aggregates; programmes. Nevertheless, there are tendencies • use of mine bulkheads;

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• chemical neutralization; earth-moving equipment involved. However, the • liquid waste impoundment liners; radioactive nature of the contaminated soils and • progressive trench disposal systems; rock also requires monitoring of personnel and • pumping of ground water; and equipment and decontamination of equipment • drainage/seepage collection and treatment and work areas. systems. Cleanup of contaminated materials. In Unconventional mining operations. In some cases, the residues of past operations have many cases, the mineral resource is of a nature been used for construction purposes off-site. The which does not easily or economically lend itself legacy of this practice is a proliferation of such to conventional mining and/or milling. Industrial radioactive wastes in structures and land which processes are available which permit the re- would not ordinarily be so contaminated. Unlike source to be extracted, but without the costs and the nuclear facilities themselves, there is a limit other burdens associated with conventional ore to the degree of restoration that can be performed processing. These processes are generally re- at these off-site properties. More regulatory ferred to as unconventional mining or milling. flexibility may be needed in such cases. For In contrast to conventional mining and milling, example, waste rock utilized in building a rail these types of operations tend to be smaller scale line may need to be treated in situ, because exca- operations where it is uneconomical or impracti- vation and reconstruction might entail other cal to excavate the ore loads. The main types are more disruptive consequences. in situ leaching (solution mining), , Water contamination. Ground and surface and byproduct recovery. If these types of smaller water resources present a greater technological scale, relatively economical facilities are prop- problem for restoration. The costs for restoring a erly maintained and operated, CEE countries and deep aquifer forces a higher reliance on natural the NIS could maintain a production level of restoration as part of the overall strategy for U3O8 without having the burdens and hazards of cleanup. A number of countries in the CEE and large surface waste impoundments. NIS regions are faced with the problem of con- In some CEE countries, both in situ mining taminated water bodies. Others are in the inves- and conventional milling have been used (e.g., tigation phase to determine the extent of such Czech Republic and Bulgaria). Heap leaching contamination. has been used in Hungary. The principle for Although exclusive reliance on some of the byproduct recovery is to take advantage of an more expensive technologies may be outside existing industrial process by diverting the op- of an individual country's resources, a com- erational — or even waste — stream for an bined strategy involving natural restoration additional extraction process. For example, for- and active water treatment (e.g. ion exchange) mer uranium mining and milling facilities in may be worth considering. In many cases, an Kyrghyzstan (Karabalta) will be converted to immediate benefit accrues when the source processing for gold. Although heap leaching and term is terminated. Uncovered waste rock byproduct recovery are fairly discrete and con- piles and other radioactive materials should be trollable operational strategies, in situ leaching isolated and stabilized, as soon as possible. requires a more carefully controlled operational Rain can interact with such waste to create sequence to be successful without contaminating additional contamination problems (e.g., acid useable aquifers. wash from the waste rock). An important facet to any restoration strategy is the benefit of partial restoration; natural resto- Current strategies for restoration ration, or a more simple approach, can be greatly enhanced when the aquifer or water body is re- The approach to restoration for contamina- stored to an improved condition, which can en- tion resulting from past practices in uranium and able nature to recover (e.g., modifying the pH by mining and milling is very similar to the addition of neutralization agents as simple as reclamation efforts usually exerted at the time of limestone). operational closeout of current mines and mills. Role of monitoring in environmental res- Selecting the scope and extent of restoration is toration. In order to adequately characterize complex, because the impacts from these facili- the extent of the problem and to measure the ties usually become evident only after a number progress of any restoration strategy, it is nec- of years. In effect, the hazard is more of a latent essary to employ an efficient, reliable, and or chronic one. The restoration effort involves well-placed monitoring system. Ultimately, one or more of the following: such a monitoring system is necessary to dem- General earthen construction. Backhoes, onstrate whether restoration has been success- bulldozers, and scrapers are the typical kinds of fully achieved.

IAEA BULLETIN, 2/1996 25 FEATURES

IAEA programmes in uranium toring and cleanup of each site were identified. mining and milling Without having a responsible or accountable en- tity, there would remain doubts regarding initia- The IAEA has basically three mechanisms in tion, execution, and completion of any rehabili- its waste management programme: tation effort. • development of documentation to assist This technical co-operation project, now into countries in implementing their own national its 1995-96 phase, consists of establishing work programmes. plans for the restoration of mining and milling • providing a forum and clearinghouse for contaminated sites. Beyond 1996, efforts will technical exchange of information. shift to the national level, in order to focus on the • promoting technical co-operation and assis- site-specific aspects of these types of facilities. tance to developing countries for peaceful use of The results of these workshops have recently been nuclear materials. published by the IAEA (as TECDOC-865). Two examples of recent IAEA initiatives in this programme are provided below. An IAEA programme focusing on radioac- Ongoing challenges tive waste standards (RADWASS) includes pub- lications of guidance in the area of uranium min- As the CEE countries and NIS move into the ing and milling, including a proposed Safety global economy, they are faced with significant Standard on restoration of facilities and the envi- challenges to compete in the private industrial ronment. sector, including uranium processing. Although The IAEA has also supported a regional tech- some of these countries still possess viable quan- nical co-operation project on environmental res- tities of the natural , they still need to toration in CEE. Most of the efforts focus on address the legacy of outdated waste manage- characterizing the type and extent of waste and ment practices, which have burdened them with in the planning of the implementation strategies large inventories of tailings and waste rock, as for the cleanup. A series of workshops has been well as other . held (1993-94) in some of the CEE countries to The international community acknowledges provide first-hand perspectives of the contami- this situation and has provided assistance to nation problem. These workshops addressed these countries through a number of means. The characterization of the waste sites, planning res- IAEA has participated in assistance efforts toration, and implementation of and techniques within the framework of its technical co-opera- for restoration. The types of sites being consid- tion programme. In doing so, the IAEA is linking ered included uranium mines and mills, but the this assistance to internationally accepted crite- project was not limited to only mining and mill- ria and standards. This is being done to assure that ing contamination (e.g., Chernobyl was in- the future development of resources in the uranium cluded). Countries with expertise in rehabilita- mining and milling industry, as well as the associ- tion and remediation of radioactive waste sites ated environmental restoration of the residues of have also taken part in the project. To the extent the past, are performed in a manner which does possible, those entities responsible for the moni- not repeat the mistakes of the past. •

Uranium open pit mining in Uchkouduk, . (Credit C Bergman, IAEA)

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