6. URANIUM MINING AND ORE PROCESSING

6.1. SCOPE

This section reviews the environmental impact of uranium mining and ore processing in Ukraine. Particular attention is given to the management of mill tailings, releases from current and former plants, and data available on contamination of water bodies within the Dnieper River basin. Radiation exposure of the public via water-borne pathways is discussed in Section 8 and uranium facilities are assessed as radiological hot spots in Section 9.

6.2.OVERVIEW OF URANIUM MINING AND PROCESSING IN THE DNIEPER RIVER BASIN

As noted in Section 3, the only uranium mining and ore processing in the Dnieper River basin is in Ukraine. Uranium exploration started in 1944 and led to the discovery of the Pervomayskaya deposit in 1945 and the Zheltorechenskoye deposit in 1946. Other ore bodies were subsequently discovered within the boundaries of the Kirovograd, Dnipropetrovsk and Nikolaev regions. Figure 6.1 shows the 21 uranium deposits discovered in Ukraine [6.1]. The largest deposits are Severinskoye, Michurinskoye and Vatutinskoye.

Uranium was first produced in Ukraine at the Prydniprovsky chemical plant, which was part of a large industrial complex on the shores of the Dnieper River in Dniprodzerzhinsk. From 1948 until its closure in 1991, about 42 × 106 t of uranium tailings and other radioactive waste was generated.

The Zhovti Vody hydrometallurgical plant has processed ores from southern Ukraine since 1959. It is located at a former iron ore production site near the centre of Ukraine’s main uranium province and is operated by the Eastern Mining and Concentrating Mill (VostGOK). The design capacity of the mill is 1 × 106 t of ore per year, but in recent years it has been operating at about 50% capacity. Currently, most of the production comes from the Ingulsky mine developed on the Michurinskoye deposit. There is also a small amount of production from the Smolino mine developed on the Vatutinskoye deposit. Ore from the Ingulsky and Smolino

mines is hauled to the mill at Zhovti Vody by dedicated trains [6.2].

There are proposals to mine the Severinskoye deposit, which has reserves of 64 000 t U at an average grade of 0.1%. Doubling of the capacity of the Zhovti Vody plant to 2000 t U/a is also envisaged [6.2].

Three ore bodies, Bratskoye, Devladovo and Safonovskoye, have been exploited by the in situ leaching method. This involves injection of sulphuric acid and a small amount of nitric acid into the ore body and pumping the uranium bearing solution to the surface, where it is recovered. This avoids the problems of solid waste management but, with unfavourable conditions, can result in contamination of groundwater.

The following sections discuss the source terms arising from the uranium mines and mills in southern Ukraine.

Ore processing plant

-Dniprodzerzhinsk

-Kirovohrad

-Zhovti Vody Uranium deposit

FIG. 6.1. Uranium ore deposits and uranium processing

operations	in	Ukraine	[6.1].	1: Vatutinskoye;
2: Severinskoye;		3: Michurinskoye; 4: Zheltorechenskoye;
5: Pervomayskoye; 6: Lozovatskoye;				7: Kalinovskoye;
8: Yuzhnoye;	9: Nikolokozelskoye;			10: Nikolayevskoye;
11: Berekskoye; 12: Krasnooskolskoye; 13: Adamovskoye;
14: Sadovokonstantinovskoye;			15:	Bratskoye;	16:
Safonovskoye;		17: Devladovo;	18: Novogurievskoye;

19: Surskoye; 20: Chervonoyarskoye; 21: Markovskoye.

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6.3.SYSTEMS FOR MONITORING POLLUTION FROM THE URANIUM INDUSTRY

In Ukraine monitoring of the environment around uranium mines and mills is based on standards developed in the 1970s. Measurements of radioactive pollution arising from liquid discharges (e.g. mine, drainage and tailings pond water) to nonstagnant receiving waters are carried out twice yearly in spring and autumn. The location of the sampling points depends on specific conditions, but typically sampling is carried out at the following locations:

(a)Above the site of release of liquid waste;

(b)At the site of runoff water release;

(c)Two to four points downstream of the release site (at the sites of possible water use, in the region of settlements, etc.).

Water samples are analysed for uranium, 226Ra and total alpha activity. The concentrations of other radionuclides (230Th, 210Po and 210Pb) are determined if the uranium and/or total alpha activities are above the permissible levels.

Radiation–sanitary monitoring at closed and decommissioned uranium facilities is carried out every three years. Reoriented uranium facilities (i.e. those that formerly processed uranium but now have different functions) are monitored every five years. Measurements are made of the radiochemical composition of drainage water and of the water bodies that receive the water.

After cessation of uranium processing, waste storage/disposal facilities are the responsibility of new enterprises that are controlled by a specially established commission that has the power to evaluate and control the condition of the waste management facilities. The commission is composed of specialists, local authorities and representatives of regulatory bodies.

In accordance with the 1996 government document Provisions of the State Monitoring of Waters, monitoring of the quality of surface and underground waters of the Dnipropetrovsk region is performed by specified State and regional laboratories. These laboratories perform measurements of the content of artificial radionuclides in the environment, namely 90Sr and 137Cs, and of total beta and total alpha activity in drinking water and in the surface waters of the Dniprodzerzhinsk (lower part), Dnieper and Kakhovka (upper part)

reservoirs and the tributaries of the Dnieper– Samara, Orel and Ingulets Rivers. The sampling is performed several times a month, and the reports are sent monthly to the higher regional authorities.

The Sanitary and Epidemiological Station No. 8 and the Laboratory for Radiation Control of Industrial Enterprises ‘barrier’ monitor the tailings at the Prydniprovsky chemical plant site and within the sanitary and protective zones. These laboratories mainly perform routine measurements; there is no interpretation of the data. Since the actual levels of contaminants in water do not exceed the sanitary norms permitting unrestricted water use, no attention is paid to assessments of low levels of contamination [6.3–6.6].

The regional administration supports scientific and research work on the ecological and toxicological state of surface waters of the region where ecological hazards are greatest. The administration also develops recommendations on minimization of any negative impacts (particularly from tailings at the former Prydniprovsky chemical plant site — Dniprovske D and Sukhachevskoye C).

Following a government decision in 1999, a field programme was developed to improve the radiological condition of uranium facilities and the environment in which they are located. The aim of the programme is to implement State policy on radioactive waste management in uranium processing in the region. The main aspects of this programme are:

(i)Closure, restoration and temporary shutdown of uranium facilities, where appropriate;

(ii)Development and optimization of regional radiation monitoring;

(iii)Reduction of the harmful impact of uranium facilities on the environment and human health.

The following tasks are envisaged within the framework of this programme:

—Identification of the negative impact of uranium facilities on the environment;

—Assessment of the contamination of the ground, water and air;

—Calculation of the dose rate to people living in areas affected by uranium facilities;

—Determination of the required expenditures for closure, redirection and temporary shutdown of uranium facilities;

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—Determination of the expenditure needed for reduction of the harmful impact of uranium facilities on the environment;

—Determination of the expenditure needed for performance of radiation monitoring and public awareness.

During the first phase of the field programme, the tasks and priorities were defined, and the administrative, legislative and financial requirements for their realization elaborated. However, this programme is mainly focused on the problem of technological reconstruction and cleanup of the contaminated areas. Owing to a lack of funds, implementation of the various tasks has been postponed and instead efforts are being focused on monitoring programmes and research related to environmental impact assessment of the former uranium reprocessing plants, tailings and uranium ore mining, as well as the scientific justification of the future regional SAP.

All investigations on the effects of tailings and former sites of underground leaching on the state of surface and underground waters in the regions of their location are provided by the specified State and regional laboratories. At present, there is no routine monitoring of water released from the decommissioned Pervomayskaya deposit; as a result, it has not been considered in estimates of current or potential radiation exposure of the local population.

The above analysis shows that there is an adequately developed infrastructure for radiation and radioecological monitoring within the zone of influence of the uranium industry. At the same time, the envisaged programme has not been fully implemented because of funding problems. Accordingly, the majority of available data is of an episodic, non-systematic nature and does not facilitate an understanding of the temporal trends in environmental data or an assessment of the effects on aquatic ecosystems.

6.4.SOURCES OF POTENTIAL CONTAMINATION AT THE ZHOVTI VODY SITE

The mining and processing of uranium ores at Zhovti Vody has negatively affected the environment as well as the sanitary state of the town since the start of operations in the 1950s [6.7–6.10]. The mining of uranium ores ceased in 1990, but

mining of iron ore at the Novaya mine is still in progress.

Figure 6.2 shows the layout of the major mining operations and the location of waste. The main sources of radioactive contamination are the three tailings sites:

(a)Tailings KBZh;

(b)Tailings Sch;

(c)Tailings R.

6.4.1.Tailings KBZh

Tailings KBZh are located 2 km from the northern boundary of the town (see Fig. 6.2) on the dividing plateau between the Zheltaya and Zelenaya Rivers. The closest settlements are Zhovti Vody, 2 km to the south, Zeleny Gai in the southwest and Veselo Ivanovka, 1.7 km to the east in the valley of the Zheltaya River. The site is an old iron ore quarry, consisting of a little pit with a depth of 10–15 m and large pit with a depth of 60–65 m. No measures have been taken to minimize seepage from the tailings area.

Tailings were deposited at this site from 1964 until 1982 by the method of hydropouring. At present, most of the tailings surface is covered with 0.4 m of clay to prevent dispersion of tailings dust. The remainder is a small pond that serves as emergency storage for the mill. The area of tailings is 54.8 ha and the total mass of 19 × 106 t of tailings occupies a volume of 12.4 × 106 m3. The tailings water has a pH of pH7.1, a 238U concentration of 0.43 Bq/L, a 226Ra concentration of 0.96 Bq/L and a total dissolved solids content of 7680 mg/L. These values can be compared with the action levels (238U + 234U = 1 Bq/L, 226Ra = 1 Bq/L) and with the permissible concentrations (PCingest) of 10 Bq/L for 238U and 1 Bq/L for 226Ra in drinking water (as per Ref. [6.4]).

Restoration of the KBZh site began in 1991 but is still incomplete because of financial problems. The project plan envisages the following covering layers: 0.4 m of loamy clay (which is already in place), 0.4 m of rock, 3.5 m of packed loamy clay and 0.4 m of black soil [6.8, 6.9, 6.11].

6.4.2.Tailings Sch

The tailings impoundment Sch is located 1.5 km to the south of the town within the limits of the Scherbakovskaya gully. It consists of two sections, old and new, separated by a dyke (see

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FIG. 6.2. Diagram of Zhovti Vody showing mines and tailings sites [6.8].

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Fig. 6.2). The old section, which is 1.6 km long and 0.6 km wide (at the dyke), has an area of 98.4 ha and a useful volume of about 5.5 × 106 m3. This section was operated from 1959 until 1980 and is now used for reserve storage only. The new section of the tailings is located in the western lower part of the gully. It has an area of 152 ha and a total mass of 34 × 106 t of tailings, which occupies a volume of 25 × 106 m3. This area was commissioned in 1979 and is still operating. The radiochemical compositions of the liquid and solid phases are given in Tables 6.1 and 6.2, respectively.

Table 6.2 shows depletion in 230Th compared with the equilibrium value at secular equilibrium (compare the specific activities of 230Th with 226Ra and 210Pb). This can be explained as follows: samples were taken from superficial layers of the solid tailings ‘mud’, whereas 230Th is partially leached and tends to migrate to the deeper layers of the tailings. To obtain more accurate estimates of the total activity of the radionuclides, a more representative sampling programme needs to be implemented. The ‘beaches’ of tailings Sch produce dust, which is a source of radioactive contamination of the air in the southern part of the surrounding settlements during summer.

6.4.3.Tailings R

Tailings R are located on the left slope of the valley of the Zheltaya River in the Razberi gully. The closest settlements are Zhovti Vody and Marianovka, situated 1.5 km to the west and southwest, respectively, and Udachny and Zaporozhets, situated 0.4 km to the east. The area of the tailings pond is 230 ha. This was originally a storage pond for iron ore milling sludge but was also used as a settling mine for uranium mine drainage waters. The solids retention system was constructed without seepage controls; however, the natural material that forms the dyke is loamy and clayey earth.

Table 6.3 gives the chemical and radiochemical composition of the liquid phase, maximum permissible concentrations (MPCs) for chemicals and PCingest for radionuclides in drinking water according to the Radiation Safety Standard of Ukraine [6.4].

The contaminated water seeps into the Zheltaya River. In some cases the seepage waters exceed the maximum permissible levels for chlorides, sulphates and even for 210Po in drinking water. There is a need to assess their long term impact on the environment.

TABLE 6.1. RADIOCHEMICAL COMPOSITION OF THE LIQUIDS IN TAILINGS SCH [6.12]

		Volumetric activity (Bq/L)
	Uranium-238	Radium-226	Lead-210	Polonium-210
Dyke water	0.74	2.6	1.2	0.4
Tailings water	2.2	8.1	0.8	0.5
PCingest	10.0	1.0	0.5	0.2

TABLE 6.2. RADIOCHEMICAL COMPOSITION OF THE SOLIDS IN TAILINGS SCH

	Year of deposition		Radionuclides and their activity (Bq/kg)
		Lead-210	Radium-226	Thorium-230	Thorium-232	Uranium-238
	1992	5 760	7 010	4730	18	1980
	2000	10 360	12 255	4860	32	1490
	2001	5 910	7 840	3265	54	1045
	2002	6 175	7 270	2400	35	1770

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