1. sz. melléklet: Conception plan for the long-term task following the abandonment of uranium ore mining MECSEKÉRC RT., 2001.

Átírás

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2 1. sz. melléklet: Conception plan for the long-term task following the abandonment of uranium ore mining MECSEKÉRC RT., 2001.

3 CONCEPTION PLAN FOR THE LONG-TERM TASKS FOLLOWING THE ABANDONMENT OF URANIUM ORE MINING Pécs, January 2002

4 CONCEPTION PLAN FOR THE LONG-TERM TASK FOLLOWING THE ABANDONMENT OF URANIUM ORE MINING Written by: Zsolt Berta head of environmental protection base József Csicsák head of environmental monitoring Supervised by: Approved by: Jenő Bánik technical director István Benkovics director general Pécs, January 2002

5 CONTENTS 1. ANTECEDENTS LEGAL BACKGROUND AUTHORIAL PRESCRIPTIONS DEFINING THE LONG-TERM TASKS SUBSEQUENT CONTROLLING, AFTER-CARE PHASE LONG-TERM CONTROL AND MAINTENANCE GROUPING THE TASKS ACCORDING TO HAZARD POINTS RADIOACTIVITY Areas with unlimited utilization Radon effluence from the abandoned mining cavities Radioactivity of isolated areas with limited utilization Monitoring the radioactive emissions Radiation protection control DAMAGE DUE TO MINING OPERATION SURFACE AND GROUNDWATER CONTAMINATION Areas with unlimited utilization Abandoned mine openings Areas with limited utilization Water decontamination systems Maintenance of hydraulic engineering structures CONDITION SYSTEM FOR COMPLETING THE TASKS ENVIRONMENTAL MONITORING Field measuring, sampling and data recording activity Laboratory analysis activities Data processing, interpreting and modeling activities Informing the authorities and the public ENVIRONMENTAL PROTECTION OPERATION Uranium removal from the surface and groundwaters Desalinization of groundwaters Maintaining the water purifying plants, the decontamination and drainage systems Maintenance and after-care of areas with limited utilization DRAFT DATA REGARDING THE AMOUNT OF LONG-TERM TASKS... 19

6 1 1. Antecedents The Government made a decision in its decree No. 2085/1997 (IV. 3.) on the termination of the unprofitable uranium ore mining in the Mecsek Mts. in 1997, and on the completion of mine closure, reclamation and environmental protection tasks till The Government decision No. 2385/1997. (XI. 26.) approved the Investment Program regarding the performing of uncompleted tasks in connection with the remediation of environmental damages caused by the uranium ore mining and milling, the remediation of environment and the abandonment of activities. From the Government, the predecessor of the Ministry of Economy, the IKIM became to be responsible for the investment, while the predecessor of the MECSEKÉRC Inc., the Mecsek Ore Mining Co. (MÉV) has become the investor. The investment has started on 1 st of January 1998, according to the plans. The time schedule of remediation of the tailing ponds had to be modified because of additional technological reasons having emerged meantime, therefore the Government changed with its decision No. 2006/2001. (I. 17.) the final completion date of the Program as 2004, having left the investment costs unchanged. The Investment Program (from this point: IP) was made based on the study titled Conception plan for the entire abandonment of the uranium ore mining in the Mecsek Mts. approved by the authorities, and its carrying out was approved by the Government in a decision. The remediation works defined in the IP have started from January 1998, while the Environmental Protection License (from this point: EPL) needed for the abandonment of uranium industry according to the concerning law was approved only in November 1998, therefore the IP wasn t able to take into account all obligations prescribed in the EPL. However, the Conception Plan being the basis of the IP has already defined subsequent maintenance jobs and long-term operational, maintenance tasks, and has contained cost plans for these tasks, but the direct plans of the financing of these tasks weren t able to be determined in the IP, because of the lack of authorial prescriptions and of remediation experiences. To solve this problem, the Government in its 2006/2001. (I. 17.) decision charged the Ministry of Economy with the elaboration of the financing of long-term tasks from This paper was made to define the long-term controlling, maintenance and operational tasks Legal background Authorial prescriptions The environmental protection requirement system of the abandonment of uranium ore mining was determined by the Environmental Protection License (EPL) issued by the South Transdanubian Environmental Protection Inspectorate under the number /1998. The section 2.2. of the EPL deals with the defining of the tasks following the completion of the Investment Program, then in Chapter II there are direct prescriptions regarding the fulfillment of long-term tasks following the term of IP. In the following part

7 2 the more important authorial prescriptions of general character concerning the long-term tasks are discussed. The direct prescriptions are discussed at the enumeration of objects. Prescriptions written in the environmental protection license No /1998. by the South Transdanubian Environmental Protection Inspectorate. I.2.2. Tasks and operation after 2002 In 2002 the activities of construction character planned in connection with the abandonment of uranium ore mining will be finished. The remediation activities will continue for a time period currently can be estimated with uncertainty, as a part of reclamation, the restoring of conditions of some environmental elements will continue for decades or centuries. Some of the remediated facilities can t be abandoned, keeping them in a required condition is also a long-term task I Monitoring Hydrogeological monitoring Its operation is expected to last for several decades, the professional tasks are nearly the same than in the previous period. Planned study programs: Immediately after remediation a detailed controlling and qualification program, which is the zero conditions assessment at one site, the process of declaration to be remediated at another site. Carrying out systematic measurements, tests by the order corresponding the expectable effects. Revision of monitoring system in every five years, evaluation, planning. Radiological monitoring The system is expected to be needed for 10 years after 2002 with less requirements and capacity. Planned studies: Detailed controlling and qualification program after completing remediation works of an object, which is the zero conditions assessment at one site, the process of declaration to be remediated at another object. On the reclaimed waste rock piles and in their surroundings, the radioactive element content of soil and plants, the gamma-dose rate in air and the radon exhalation is tested quarterly. Rock movement monitoring The existing subsystems of monitoring are suitable for this task. The surface measurement network is planned to be established I Water treatment The limited extent and controlled drain of area affected by mining is needed for long time to prevent the spreading of unfavorable effects. The water quality after the water filling predicted to last for 33 years can be estimated hardly. The mine water pumping is a long-term task.

8 3 The time period of remediation in connection with tailing ponds, the finishing of water pumping is also expected to be long-term. It is necessary to take care of the treatment of pumped water for achieving defined limits, as condition of leading it into the recipient. The operation of water treatment plant involves tasks of waste disposal I Maintenance In the course of remediation, the using of technical methods requiring the less maintenance has been a principle. After the entire completion of remediation (finished mine water pumping, finished decontamination, finished water clarifying), there will be further tasks to keep the constructed structures in required conditions and controlling them by operating and maintaining: the cover layer, the vegetation, the water drainage system, and the monitoring networks. II.1. General liabilities associated with the activity In the course of activity the tasks has to be completed, in the defined way and at the defined degree. The investments that dragged on or failed, the maintenance, operational and monitoring activities related to the completed remediation works and their long-term development requirements have to be taken into overall consideration. The organization, personal and economical conditions needed for performing the remaining tasks should be developed. 2. Defining the long-term tasks For the long-term successfulness of technical interventions of reclamation and environmental protection purposes carried out according to the plans of IP and according to the authorial prescriptions controlling, monitoring and maintenance tasks should be performed that are of different degree, character and term for each objects. These tasks are divided into two phases depending on the amount and character of the required activities and according to the methodology accepted internationally in the remediation practice: The first phase of 5 years, which contains generally wider and more diverse control and more intensive after-care, while the second long-term phase requires only limited control and after-care as needed.

9 Subsequent controlling, after-care phase The first phase representing practically an about 5-years long term after the completion of the remediation works of each objects requires considerable amount of controlling, monitoring and after-care activities. This term requires a more frequent and rigorous control in space and time as well, and considering the studied parameters, too. Its purpose is to verify the long-term stability and efficiency of the remediated environment and the completed technical interventions, to justify the fulfillment of the prescribed limit values, to carry out the needed maintenance interventions for the keeping the efficiency of constructed facilities (rainfall water discharging systems, cover layers, vegetation cover for the protection against erosion, etc.), and to repair these facilities, restoring their original conditions. In this phase biological monitoring is required to observe the conditions of the completed planting, which one directs the replacements and corrections taking into account the soil forming and the features of the biotope. In the course of biotope development, the selfsustaining system forms in this phase, ensuring the protection against the erosion. The repairing of eroded areas forming as consequence of the planting failed to come about or of other causes, the configuration of the needed maintenance and operation system of hydraulics engineering structures for the discharging rainfall. The optimization based on modeling of water damage preventing systems planned for long-term operation, the development of technologies in such a way that makes the cost reduction and the accordance with the new norms of the European Union possible should be completed in this phase. In the field of uranium removal, especially around the waste rock piles, the discovery of possibilities of using passive, low-cost natural technologies. In this phase the expected time, cost and technology requirements of interventions should be refined, by the help of the intensive monitoring data analyses. The elements of the long-term required monitoring system, the frequency of control, the order of maintenance and operation should be determined till the end of the after-care period Long-term control and maintenance The second phase contains the environmental monitoring and maintenance tasks of the remediated objects as needed, and its term can be determined on the basis of examination performed periodically (in every 5 years according to the Environmental Protection License), however, it is evident just now, that these activities will have to be continued after years around some objects (e.g. abandoned mining cavities, tailing ponds). In the long-term phase the operational and maintenance activities will go on in the remediation systems, the northern mine plants will be filled with water in this period, the uranium removal from the mine waters will have to be continued. The engineering structures constructed in the course of remediation activities will have to be inspected, the maintenance works of needed extent will have to be carried out.

10 5 The composition, frequency and denseness of inspections can be developed according to the experiences of the subsequent monitoring phase. Considerable part or in optimal case the majority of the elements studied systematically till that time can be omitted, but the adequately isolated, radioactively contaminated material cannot get into the environment even in the future, too, therefore it will have to be re-examined systematically. The analysis of such sensitive parameters should be preferred, that predict the possible environment pollution in advance, so the intervention can be carried out in time. The southern phase of water remediation for the removal of salt contamination can be finished in this stage. The filling of the mine cavities of the northern region may require the intensification of uranium removal as well. The informing the authorities and the public will serve for the so-called reminding in this phase. The protection of objects that cannot be disturbed should become a community task. 3. Grouping the tasks according to hazard points Finishing the Investment Program such hazard points have still remained that require control and gradual elimination. After finishing the mining all the factors should be taken into account that verify the operation of monitoring systems. The following grouping lists the main hazard points according to the origin of contamination. The factors are discussed subordinated to them, that endanger the final results of completed works and remediated objects (erosion, desiccation, plant decease, etc.) Radioactivity Areas with unlimited utilization Principally all contaminations were removed from the areas with unlimited utilization, and this had to be verified with detailed survey including the analyses of every contaminants after the remediation. The authority issues the declaration on the inactivity based on this survey and on its own controlling analyses. However, such contaminations can remain (because of the character of the radioactive polluting material) that have remained unknown even after a very circumspectly accomplished survey, and perhaps they can be mobilized in the future (it should be presumed primarily in the case of groundwaters, but the remaining of small contaminated soil spots also cannot be excluded without doubt). The measurements of subsequent control: Gamma dose rate measurements. Air 222 Rn concentration and soil surface 222 Rn exhalation measurements. Soil and plant sampling, determination of the specific radioactivity and radionuclide composition of samples.

11 6 The control should cover the 5 years long subsequent control period only; if no contamination is found during this period, the problem can be finally closed with the winding up of the possibly revealed contaminations. Where planting is prescribed in the licenses, proposal for the possible replacement can be made for the new users or owners according to the measurement results of the biological monitoring Radon effluence from the abandoned mining cavities Above the abandoned mining cavities because of tectonic and loosening originated fractures extra radon effluence is expected, primarily on those areas, where both the cavity system and the ore-bearing layer is situated close to the surface (max. several 100 m depth). Such situation can be found on the area of the former Mine Plants #I and #III. Additionally, they affect working and residential areas as well (Kővágószőlős). The following analyses have to be performed on these sites: Soil gas 222 Rn concentration and soil surface 222 Rn exhalation measurements. Integral radon measurements in open place, working and residential environment with SSNTD detectors (solid state trace detectors). Continuous radon monitoring of closed mine cavities (Northern Adit, open shaft of Mine Plant #I). The interventions and radon removal should be carried out depending on the rate of revealed radon effluence, the developed radon concentration and the legal prescriptions expectedly becoming stricter from Radioactivity of isolated areas with limited utilization On these areas the isolation from the environment was made in such a degree, that the authorial prescribed limit values will be kept of great surety. In the subsequent control phase the stability of this isolation should be studied. Subsequently, in favor case, the denseness of monitoring can be lowered radically, but cannot be terminated because of the potential hazard situations discussed in the introduction. In addition, the objects with low radioactive contamination (small waste rock piles, heap leaching areas) should be distinguished from the radioactively strongly contaminated tailing ponds and the Waste Rock Pile #III transformed into central waste disposal facility. The monitoring to be carried out is as follows: Visual inspection of possible damages, alterations. Gamma dose rate measurements. Air 222 Rn concentration and soil surface 222 Rn exhalation measurements. Soil and plant sampling, determination of specific radioactivity and radionuclide composition of samples through gamma-spectrometric method. Study of migration of radioactive elements (vertically in the cover). Study of migration of radioactive elements (horizontally into the environment). The results of samples should be compared with samples coming from geologically-pedologically similar environment, which is free from the industrial activity (background).

12 7 In the surroundings of the tailing ponds and the Waste Rock Pile #III: integral radon measurement with SSNTD technique, and with fix installed monitoring stations. Biological monitoring study of the planted vegetation and the developing biotope. Inspecting the stability and water balance of cover layers with geophysical methods (can it fulfill its task to isolate radioactivity and to reduce infiltration). As a result of the various monitoring, considerable maintenance, repair and function keeping work should be taken into account in this topic. At the end of the 5 years long after-care period, through the evaluation of measurement results a forecast should be made on the successfulness of isolation, the necessity of possible interventions for the selfsustaining Monitoring the radioactive emissions Emission of radioactive materials will occur in the long term period as well (air, waters, wastes, utilizable materials, etc.), which is regulated by the 15/2001. (VI. 6.) KöM (Ministry of Environmental Protection) decree. The monitoring activities for these emissions will have to be continued till the end of the emissions. Gas effluent Radioactive gas effluent is released practically only from the technological system of mine water purification. Elements of effluent monitoring: meteorological station (provides data for the modeling the contamination spreading), continuous aerosol sampling, the determination of natural uranium (U nat ) release into air is based on the measurement of long-life alpha radioactivity of samples. Liquid effluent The sole-point water discharge (into the stream Pécsi-víz) after the purification is controlled continuously. Its monitoring elements and regularity is discussed in chapter 3.3. The radioactive element, U nat and 226 Ra content of effluent should be monitored continuously. Solid waste disposal The remnants of chemical water treatment, the desalinization, and the technological wastes of mine water treatment will are placed into the waste disposal constructed on the Waste Rock Pile #III. Systematic analysis of radioactive element content. Purposeful monitoring the environs of the disposal.

13 Radiation protection control Considerable part of work sites with radiation hazard will cease finishing the remediation activities. However, several work sites and jobs will remain of radiation hazard: the radiation protection monitoring will have to be continued till the end of these activities, according to the current 16/2000. (VI. 8.) EüM (Ministry of Health) decree Damage due to mining operation After the abandonment of mining activities the shafts have been backfilled. Land movements are expected because of the filling of cavities by water, the termination of previous, long-lasting depression and the own processes of cavity system. According to the decision No. 4954/2000/3. by the District Office of the Mining Bureau of Hungary, the following land movement monitoring has to be in operation in the first 5 years, to delete the mining plot and to know the re-utilization accurately: Leveling network (121 reference points). Highly sensitive 3D deformation measurement (on 14 points). GPS network (10 reference points). Systematic inspection of the level of shaft backfilling. In the long-term phase, this system will be winded up gradually according to the possibility for exemption. Intervention is expected only at the backfilling of shafts, and at the maintenance of engineering structures and monitoring elements. Tasks are the operation, the continuous interpretation, modeling and informing as needed, the developing and archiving databases Surface and groundwater contamination The remediation aims and works of the uranium ore mining in the Mecsek Mts. were strongly influenced by the hydrogeological position of the mining area. The aquifer formations of underground mining in the Western Mecsek Mts. are in connection with aquifer formations of drinking water resources both on the north and the south. E.g. the tailing ponds are situated between the drinking water reserves of Tortyogó and Pellérd, on the surface of the aquifer formations of the two reserves, the contamination leaving them endangers directly the aquifer formations of water reserves. To ensure the long-term protection of potable water reserves such facilities were constructed in the course of Investment Program, that are targeted to prevent the contamination of surface and groundwaters, and to treat the already contaminated waters. The maintenance and long-term operation of these decontamination systems will provide the prevention of water pollution, which can be verified through systematic monitoring Areas with unlimited utilization On areas with unlimited utilization since all contaminants as well as the contaminated soil were removed from here only subsequent inspection tasks of limited period

14 9 (generally five years) should be performed, according to authorial prescriptions. Such areas are e.g. the Heap Leaching Pile #I, the territory of the Ore Mill Plant, where the successfulness of remediation should be verified through measurement time series in existing shallow groundwater monitoring boreholes Abandoned mine openings In the course of uranium ore mining underground cavities of approximately 18 million m 3 volume were produced. Their most part (cavity systems of Mine Plants #I-#II-#III-#IV) forms a contiguous and interconnected cavity system, while the underground areas of Mine Plant #I represent an independent cavity system. After abandonment the cavity system fills up with water, which leaches contaminants from the loosened rocks in concentration above the limit values, as a consequence of the altered geochemical conditions due to mining activities. The contaminated waters can migrate from the filled cavities left to themselves, therefore other aquifer formations can be contaminated. Accordingly, the abandonment had to be done in planned way, ensuring that the mine waters come to the surface on a single point. Other situation can be found in the Mine Plant #I, where the entire filling up cannot be allowed for the time while the water in the cavity system contains dissolved uranium above the limit value, since it endangers the water reserves of Tortyogó and Pellérd. A depression of almost 100 m should be maintained in the cavity system till the adequate water quality will be achieved. The control of filling up and the treatment of contaminated water filling the cavity systems will require both monitoring and operational tasks in long-term. Concerning prescriptions: 6 th, 7 th, 8 th, 11 th and 12 th paragraphs of EPL II.3.1. point Monitoring The monitoring is a long-term task in the case of mine cavities, considering the slow process of filling up. Therefore the followings have to be monitored long-term: The process of filling up of mine cavities should be controlled on monitoring points installed in the period of IP. It takes approximately years, according to the current studies. The depression developed in the course of mining, its change during the filling up should be monitored for the prediction of communication towards other aquifer formations. Monitoring system should be maintained and operated to control the water quality of various aquifers around the objects. The depression effect of water pumping in the Mine Plant #I should be monitored, to keep the water reserves of Tortyogó and Pellérd secure. It should be verified, that the adequate protection exists around the Waste Rock Piles #I and #III, as a result of this depression.

15 10 During the filling up, the quality of cavity filling water has to be controlled systematically through analyzing different components (radioactive elements, heavy and toxic metals, hydrocarbons) Mine water treatment After finishing the uranium ore mining, waters with high uranium content should be expected for a long period, that have to be the uranium removed from. Expectedly 3-4 t/year in the first period, and later 2-3 t/year uranium will have to be extracted from the water. The depression effect of Mine Plant #I should be ensured for a long period in a way that meets the requirements (keeping the water level prescribed for mine cavities), from the originating water of high uranium content the uranium has to be removed, the controlled water direction and the transformation of uranium extracted from water into manageable form have to be ensured. After the northern mine plants will fill up that is expected to happen in about years the uranium removal from the mine water discharged through the Northern Adit highly probably will be necessary. Pumping and treating the water of high uranium content from the Mine Plant #I For the protection of the water reserves of Tortyogó-Pellérd, the water level in the cavities of Mine Plant #I the water level should be kept at about 100 m depth from the surface. The uranium should be removed from pumped water after pumped out. Regarding prescriptions: Water operation license of the DDVIZIG (South Transdanubian Water Authority) No. 6236/ EPL of DDKÖFE (South Transdanubian Environmental Protection Inspectorate), No /1998., 12 th paragraph of point 3.1., 1 st paragraph of point The depression effect of Mine Plant #I should be ensured for a long period in a way that meets the requirements (keeping the water level prescribed for mine cavities). The water level in the cavities has to be kept on the +65 m a.s.l. From the pumped out water of high dissolved uranium content the uranium has to be removed adequately, the controlled water direction and the transformation of uranium extracted from water into final product of peroxide form have to be ensured. The single-point discharge of treated water into the surface recipient has to be provided. The quality of pumped and treated water, and the efficiency of treatment technology should be monitored. Treatment of waters from the northern mine plants It is expected that the dissolved uranium content of water will increase in the future, after the mine cavities will filled up (Water protection plan of the abandonment of uranium ore mining in the Mecsek Mts., BKMI Ltd. 1998), and the water will get to the surface as free outflow through the Northern Adit. The uranium should be removed from this water, too, its volume is expected to be about 500,000 m 3 /year.

16 11 The removal of uranium from the waters of Mine Plant #III, their analysis, fitting the discharge system into the control technique system, as needed. Forecasting the appearance of springing waters, monitoring the temporal changes of water quality Areas with limited utilization Those areas belong to the group of areas with limited utilization that contain polluting or contaminated materials, waste rock, tailings or contaminated soil, which represents potential for surface and groundwater contamination. On these areas the spreading of contamination is prevented by some kind of isolating layer (cover) in the way that it reduces the infiltration of precipitation water, thus the leaching of polluting materials as well. Amongst the areas with limited utilization mainly the tailing ponds will require long-term monitoring and maintenance activities, considering that the cover layer placed in the course of remediation plays important role in the prevention of infiltration of surface waters. In addition, the waters springing from below the waste rock piles represent important hazard points for the surface and groundwaters of the environment, since they have surely high dissolved uranium and possibly other heavy metal content. In the period of subsequent control phase the integrity of cover layers and the result of planting should be checked visually, the quality of water springing from below and flowing away from the objects should be monitored, monitoring system should be maintained and operated to control the quality of groundwaters in the surroundings of objects, around the waste rock piles primarily considering the radioactive elements and toxic heavy metals, while around the tailing ponds monitoring primarily the dissolved inorganic salts, the stability and protection efficiency of engineering interventions accomplished in the course of remediation should be verified through measurements, increased maintenance activity should be performed to keep the isolation capability of the cover layer, for the development of self-sustaining ability of the planted vegetation and plant associations, the replacement of plants and the promotion of appropriate vegetating should be done as necessary (e.g. systematic mowing), the emerging erosion damages have to be repaired, the waters of high dissolved uranium content springing from below the waste rock piles (Waste Rock Piles #I, #II, #III) have to be collected and diverted into the cavities of Mine Plant #I or into the Mine Water Treatment Plant for treatment. In the long-term period reduced monitoring activity of the quality of surface and groundwaters should be performed, maintenance tasks should be fulfilled periodically, as needed,