Asian cleanup - what is needed?8 August 2018
Funding is the main barrier to cleaning up legacy uranium sites in Central Asia, as NEI reported in May. Rocco Silveri, Adriaan van der Meer, Pascal Daures, Martin Andersen and Uwe Walter, discuss the extent of the remediation work needed.
URANIUM-RELATED ACTIVITIES IN CENTRAL Asia go back to the mid-1940s, when mining started in the mountainous areas above the Syr Darya River and the Ferghana Valley. When production stopped, the mining and milling sites were abandoned and the dumps of waste rock and low-grade uranium ore, piles and tailings ponds grew into a serious threat.
About a billion tons of mining waste is currently stored, in some cases inadequately, around functioning and abandoned uranium mines in Kazakhstan, the Kyrgyz Republic, Mongolia, Tajikistan, Turkmenistan and Uzbekistan.
Few protective measures were in place and little remediation has been carried out. Measures in place generally do not meet international standards or best practice. Mine shafts, tunnels and adits remain open and accessible to local people and livestock. Waste rock and low-grade ore dumps and tailings piles are poorly covered, and in some cases exposed to the elements.
Rainwater and groundwater ingress at mines, dumps and piles poses imminent danger of contamination of drinking and irrigation water.
Most sites are in seismically active zones, which are prone to earthquakes and landslides. Streams and rivers can be fast-flowing and prone to flooding, causing erosion and mudslides.
Tajikistan, the Kyrgyz Republic and Uzbekistan have most of the uranium legacy but not the capabilities and means to deal with it.
A strategy on remediation priorities was developed by the International Atomic Energy Agency (IAEA). Its report identified priorities for site remediation activities in Kazakhstan, the Kyrgyz Republic, Tajikistan and Uzbekistan.
International organisations are providing support to the region. Initial efforts were conducted through small uncoordinated projects. The need for coordination was recognised in 2012, and the Coordination Group for Uranium Legacy Sites established by the IAEA.
The European Commission has played a key role. In 1995, in the framework of the TACIS (Technical Assistance to the Commonwealth of Independent States) nuclear safety programme, remediation options were first assessed and ranked. Other studies focused on more specific areas.
Since 2013, the EU has funded, under the Instrument for Nuclear Safety Cooperation (INSC), environmental impact assessments and feasibility studies in seven priority sites identified in the IAEA baseline document: Min-kush, Shekaftar and Mailuu-Suu in the Kyrgyz Republic, Istiklol (formerly Taboshar) and Degmay in Tajikistan and Charkesar and Yangiabad in Uzbekistan. The EC programme included a regional project to establish a watershed monitoring system for the Syr Darya basin and a project with the UNDP to raise awareness in the population.
The seven priority sites are all located in the watershed of the Syr Darya river, which runs through the Fergana Valley, populated by 14 million people across Uzbekistan, Tajikistan and the Kyrgyz Republic. Radioactive and toxic material in the river system will have trans-boundary effects on the health of the population, the environment, and the economic development of the region.
Remediation plans for six sites are ready subject to funding. Documentation has been developed that will serve as a basis for tendering the proposed remediation work. A remediation plan for Mailuu-Suu is expected to be ready in 2019.
Several experienced European organisations including Germany’s Wismut, Wisutec, GRS and GEOS, Sweden’s Facilia and the Belgian nuclear research centre SCK•CEN were involved in the preparation of studies and design documents for remediation of the mines. All the results have been independently peer reviewed by a team of experts that was set up by IAEA.
Min-Kush is 130km south Bishkek in the Kyrgyz Republic. As a manufacturing hub, Min-Kush was home to more than 20,000 people. Now it has 3200.
Of special concern is the risk of radiological and chemical impact from mine waters used for drinking and irrigation. Mine openings and the dilapidated uranium processing facilities represent a significant to high risk.
Waste rock dumps pose a risk due to water infiltration spreading contamination via erosion, and exposure to frequent landslides.
Various remediation options were assessed in the EU project. These include closing shafts or adits and sink-holes; demolishing dilapidated processing facilities and various activities to drain or divert water at three waste rock dumps.
Shekaftar houses 3500 people in southwestern Kyrgyz Republic, 10km from Uzbekistan. The complex has three closed mines and eight mining waste disposal areas, with about 700,000 cubic meters of waste.
A community previously working in the uranium mine now has a 70% unemployment rate. It has radioactive waste rock dumps scattered around the village, including right next to a school.
One waste rock dump is subject to erosion by the Sumsar River. Many mine openings pose a high risk to the public in general.
The remediation options proposed include closing shafts, adits and sinkholes, demolishing contaminated mining facilities, constructing diversion channels and river bank protection and relocating waste rock dumps.
Mailuu-Suu in the southern Kyrgyz Republic, 25km from Uzbekistan, has 25,000 inhabitants. From 1946 to 1968 its Zapadnyi Mining and Chemical Combine mined more than 9000t of uranium for the Soviet nuclear programme.
More than 2 million m3 of tailings were generated and disposed of at 23 sites spread over 50ha. Now the many unsecured deposits of uranium tailings on the steep and unstable mountain slopes around the city pose serious risks to the local population and the environment.
Major risks include the release of toxic contaminated material from the tailings sites on the slopes next to the banks of the Mailuu-Suu and Ailampa Sai rivers. Flash floods, mudslides, or earthquakes could cause dams and embankments to collapse, releasing contaminated material into the rivers and washing it downstream into Uzbekistan. Groundwater contaminated by mining waste may be used for drinking and irrigation.
During 2004-2013, partial remediation was undertaken with support from the World Bank to relocate an unstable tailings facility by the Mailuu-Suu River and a waste rock dump by the Kulmen Say creek. The remediation required was greater than originally envisaged and a new plan is still under way.
Degmay, in the Northern Sughd province of Tajikistan, has one of the largest tailings dumps of uranium mining wastes in Central Asia. Uranium mining operations peaked between 1963 and 1993.
The unprotected tailing site, has an estimated 36 million tonnes of radioactive toxic waste in an area of 90ha and with total activity estimated at 150TBq. The site is 10km from the regional capital Khujand; the population of the wider area is more than one million.
There are risks from direct exposure to water from certain wells, which contain elevated doses of uranium. Contaminated infrastructure, especially tailings pipelines with radioactive residues, poses risks to the general public. A geomechanical analysis showed that the tailings pond dam may become unstable under seismic loading or if the phreatic surface raises.
The remediation options proposed include reshaping the tailings pond dam, removing the contaminated infrastructure, re-contouring the tailings pond and placing a multilayer cover over it.
Istiklol (formerly Taboshar) has 14,000 inhabitants and is in the Northern Sough Region of Tajikistan, 40km from the regional capital Khujand. The uranium mine, dating from 1936, was one of the oldest in the former Soviet Union.
The city had a peak population of almost 39,000 in 1979. The mining facility extends over some 400ha. Although mining operations ceased in the 1970s, the legacy objects were never remediated.
There is concern about the radiological and chemical impact of contaminated mine water used by the population for irrigation and drinking. Most of the identified shafts, open adits and sinkholes pose a significant risk to the local population due to erosion, direct radiation and ingestion. Of particular concern is a school surrounded by contaminated waste rock dumps.
Remediation measures identified by the study include closing shafts, adits and sinkholes, demolishing contaminated infrastructure, a water treatment plant and relocating waste rock dumps, in particular those close to the school.
Charkesar village is 140km east of Tashkent in Uzbekistan. Here mining was done by conventional methods and by underground leaching down to a depth of 280m.
The mine closed in 1995. Today Charkesar has some 3500 inhabitants.
The site can be divided in two areas; one of which is being remediated with funds from the Uzbek government. Radiological risks are associated with contaminated mine water. In addition, geomechanical risks are posed by mine openings.
Remediation measures include closing the mine openings, diversion channels for rain water and demolishing abandoned facilities.
Yangiabad, 70km east of Tashkent in Uzbekistan, saw uranium mining for 40 years ending in the 1980s. Waste rock piles extend over an area of 50km2, and contain about 2.6 million m3 of radioactive waste.
After the mine closures, the population fell by 90% to 1000. Waste rock dumps on riverbanks pose risks due to floods and erosion processes that can spread contaminated material downstream. There are significant geomechanical risks from mine openings accessible to the general public. Old ore bunker buildings also represent a high risk.
Remediation measures identified include closing shafts, adits and sinkholes, demolishing ore bunker facilities, constructing diversion channels and river bank protections and relocating rock dumps.
A way forward
In 2017, a Strategic Master Plan (SMP) for the environmental remediation of uranium legacy sites in Central Asia was prepared under the aegis of the IAEA by the Coordination Group for Uranium Legacy Sites and signed by the authorities of the Kyrgyz Republic, Tajikistan and Uzbekistan. It had the input from the countries and built on the findings of the EC studies, CIS projects and others.
As the joint programme of all key parties, the SMP is a shared framework guiding individual actions of the parties.
The studies funded by the EC estimate the total remediation cost for those seven sites at €85 million including financing, project management and monitoring.
To cover this cost, the Environmental Remediation Account for Central Asia (ERA) was established in 2015 by the European Bank for Reconstruction and Development (EBRD).
The aim of the fund is to pool donor contributions to assist the Kyrgyz Republic, Tajikistan and Uzbekistan to remediate seven priority sites already agreed. The Central Asian countries have signed Framework Agreements with the EBRD setting out the conditions for implementation of the project.
Almost all of the preparatory work is done for the seven priority sites. The techniques to be used are known and the cost estimates are calculated. The work has been independently peer reviewed.
The coming period will be crucial for the start of the remediation works, as a way to promote sustainable development in Central Asia. The outcome of a pledging conference to be held on 8 November 2018 will be a decisive moment.
Author information: Rocco Silverii, Scientific officer at the European Commission Joint Research Centre in Petten; Adriaan van der Meer, Former EU head of delegation to Central Asia; Pascal Daures, Head of nuclear safety, preventive and corrective actions at the European Commission; Martin Andersen, Senior programme manager Nuclear Waste at the European Commission; Uwe Walter, Head of the mining department at WISUTEC Umwelttechnik GmbH