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Significant progress has been made in cleaning up some of the legacy waste from historic uranium mining in Central Asia, but much remains to be done, with additional donations from the international community needed to complete this vital remediation work, the European Bank for Reconstruction and Development (EBRD) says.

The Fergana Valley, which links Kyrgyzstan, Tajikistan and Uzbekistan, is home to 14 million people and one of the most fertile and densely populated areas of Central Asia. The valley could be negatively affected by the release of radionuclides and heavy metals from tailing dumps and heaps resulting from historic uranium mining in the area. The Syr Darya River, which runs through the valley, is one of the principal rivers in Central Asia.

A Strategic Master Plan for the environmental remediation of former uranium sites in Central Asia was published by the International Atomic Energy Agency (IAEA) and European Commission in May 2018. The plan identifies seven former uranium production sites in the region as the highest priority: Mailuu-Suu, Min-Kush and Shekaftar in Kyrgyzstan; Degmay and Istikol in Tajikistan; and, Charkesar and Yangiabad in Uzbekistan. The plan states, "The release of radioactive and toxic legacy wastes into rivers is inevitable as long as the sites remain unremediated: it is not a question of 'if' but of 'when'".

The strategic and integrated approach set out in the plan was intended to provide confidence - in particular among potential donors - that remediation will be addressed in a timely, coordinated, cost-effective and substantial manner, and in accordance with international conventions and agreements. The total cost of remediating the seven sites is estimated at around EUR85 million (USD94 million), with Kyrgyzstan's Mailuu-Suu site representing about EUR30 million of this.

The EBRD established the Environmental Remediation Account for Central Asia in 2015 to pool donor contributions to remediate the seven priority sites. To date, pledges and funding of about EUR35 million have been provided by Belgium, the EU, Norway, Lithuania, Switzerland and the USA. However, to close the remaining shortfall and successfully implement the programme, a further EUR50 million is needed from the international community.

Progress at Mailuu-Suu

The London-headquartered bank last month invited journalists to see the progress made in the remediation of the Mailuu-Suu site in Jalal-Abad Province, in western Kyrgyzstan, and to highlight the work that remains to be done.

In the Mailuu-Suu area, uranium was mined and milled between 1946 and 1967 as part of the Soviet nuclear programme. During this period, some 10,000 tonnes of uranium oxide were produced there. The underground mines are subdivided into five mine fields and accessible via three shafts. The Kara Balta Mining Combine was set up in the 1950s to mine and treat this ore in the north, near Bishkek.

Mailuu-Suu (a former closed city) has a population of about 25,000, with a light-bulb factory the only significant employer. Many unsecured deposits of uranium tailings on the steep and unstable mountain slopes around the town pose serious risks to the health of the local population and the environment. In addition, groundwater contaminated by mining waste can pose a risk when used for drinking and irrigation.

The site of one of many landslides on the hills surrounding the Mailuu-Suu River (Image: WNN)

Radioactive substances are stored in 23 tailings ponds (total volume around 2 million cubic meters) and 13 mining debris heaps (total volume about 0.9 million cubic meters) situated along the Mailuu-Suu River, which feeds into the Syr Darya River. Some of these tailings have already been damaged by landslides, mudslides and floods, and some are in high-risk areas where major landslides are expected. A dam rupture of tailings pond #7 occurred in April 1958 causing spills of 6000 cubic meters resulting in contamination of the Mailuu-Suu River. Tailings pond #3 is currently considered to be most at risk as it is threatened by a major landslide. A landslide in May 2002 just upstream from that tailings pond initially caused a blockage in the Mailuu-Suu River and subsequent partial destruction of the former Isolit uranium processing plant.

About EUR11 million of remediation work was carried out at Mailuu-Suu between 2004 and 2013 with support from the World Bank's Disaster Hazard Mitigation Project. A geologically unstable tailings facility on the banks of the Mailuu-Suu River was moved to a more secure and stable location, and a waste rock dump on the banks of the Kulmen Say creek was similarly relocated. Another waste rock dump on which homes had been built was also relocated, requiring the resettlement of the residents.

In August 2017, the Kyrgyz government ratified a framework agreement with the EBRD, which had been signed in January of that year. Ratification of the agreement means all the basic conditions are in place for remediation work to begin at several uranium legacy sites in the country.

Under a contract awarded in 2017, and with funding from the EU, a consortium of companies is conducting an integrated environmental impact assessment and feasibility study for the management and remediation of Mailuu-Suu. The consortium comprises: GeoConsult of Austria; Belgium's Nuclear Research Centre (SCK-CEN); Wismut and Wisutec of Germany; and, Facilia of Sweden. Wismut and Wisutec have experience of remediating former uranium mines in the German states of Saxony and Thuringia.

Relocating material

Ulf Barnekow, head of Wismut's mining remediation department, said there are three problems with the tailings ponds and waste rock dumps at Mailuu-Suu.

"First, we have surfaces with only very thin earthcover. In the past there was access to the tailings, which is radioactive material. With tailings close to the surface, there is the problem of dust. The second problem is seepage water that percolates through the tailings, resulting in uranium in the water."

He said the most critical problem is the geotechnical stability of the tailings dams. "If such a dam here fails, the undersludge can flow out and can be transported through into the valley into the town of Mailuu-Suu. And the contaminated material will be transported through the Mailuu-Suu River to the next state, as well as Uzbekistan. So there is also a transboundary problem. But the first and main problem is for the people living in Mailuu-Suu."

Tailings pond #2 at Mailuu-Suu (Image: WNN)

Barnekow said the main geotechnical problems usually arise in the wet season, which is in the spring. The catchment area for the rain and the snow is about 24 square kilometers upstream.

"There's no forest, therefore if there is snow melt or heavy rain, you have very fast flowing discharge of the water of the catchment area and therefore you have an enormous flow rate here into the river."

He said the consortium is now at the stage where it has determined the preferred option for remediating the tailings adjacent to the Ailampa Say creek, which runs into the Mailuu-Suu River.

"We have some boundary conditions that we have to firstly look at," he said. "The first and most important thing is that we must not transport tailings through the town of Mailuu-Suu. It is not acceptable."

The solution, Barnekow said, is that tailings held in ponds at risk will be relocated to more stable ponds. For example, material in tailings pond #13 will be relocated to pond #1, while pond #2 will be relocated to pond #4. The solution, he said, is to put the material together "in one safe place", and in the process reducing the surface area of the ponds.

"This is a difficult geotechnical task because these tailings are very often soft, so they may need to be conditioned before they can be transported and put here on the tailings pond.

"The remediation could achieve a situation that is safe in the long term and will also enhance the situation here in Mailuu-Suu, especially for the people living here," Barnekow said.

On 2 May this year, the Kyrgyz parliament passed a resolution ordering the government to draft legislation for a ban on uranium exploration and mining in the country. On 31 October, the parliament passed a bill on this. Several overseas companies currently hold uranium exploration licences issued by the Kyrgyz government.

Researched and written by World Nuclear News

Date: Thursday, 14 November 2019
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