BGR Bundesanstalt für Geowissenschaften und Rohstoffe

TC Kyrgyzstan: Reduction of Hazards Posed by Uranium Mining Tailings in Mailuu-Suu

Report of the project:

Status Quo:
In the Mailuu-Suu area (Kyrgyzstan, 100 km NW from Dschalal-Abad), uranium ore has been mined and processed from 1946 to 1968. The resulting tailings and waste rocks have been deposited in nearby dumps together with ore material of inefficient low uranium content. Altogether, around 3 million m³ waste materials (TACIS 2003) with relatively low radioactive inventory has been deposited in morphologic depressions and covered provisionally.

In response to the environmental impact of the ore mining and milling, the Soviet government has constructed a central water supply facility using uncontaminated river water upstream the mining area. The water facility was designed with the aim to provide drinking water for 20 000 people and, therefore, never achieved to serve all residents of Mailuu-Suu. Moreover, the water supply facility degraded during the last decades and, consequently, an increasing number of households obtain their drinking water from deep artesian wells or utilize simple dug wells in the young gravels of the river valley.

View at tailing no. 7, which is separated from the flood plain of Mailuu-Sai River (left) only by a gravel dam (middle)View at tailing no. 7 Source: BGR

Due to the location in a tectonically highly active region, the dumps and tailings stability is threatened by landslides, which might be triggered by seismic events or seasonal heavy rains. Several tailings and dumps have been deposited in the vicinity of instable mountain slopes and, thus, their radioactive inventory might be eroded and transferred into the river. Furthermore, landslides may block and retain the local rivers Mailuu-Say and his tributaries such as Kulmin-Say - as already happened in 1992 and 2002 -, resulting in flooding of nearby dumps and tailings. Both scenarios are combined with erosion and solution processes and, thus, mobilization of the radioactive inventory. The mobilized radionuclides would not only affect the local water resources, they might also be transported beyond the Uzbek border 25 km downstream of Mailuu-Suu.

Objectives:
Against this background, the World Bank implemented a 17 million $ disaster hazard mitigation project in Mailuu-Suu. In frame of this project, BGR was carrying out the hydrogeological baseline study with special respect to the planned geotechnical remediation of the radioactive waste deposits. Furthermore, a long-term groundwater monitoring network has been implemented in cooperation with the Kyrgyz Ministry of Emergency Situations (MoE).

The initial stage of the project comprises the characterization of the hydrogeological frame as well as the current distribution of contaminants with respect to physico-chemical and radiological parameters. Subsequently, the potential impact of the planned remediation activities to the local surface water bodies and aquifers has been evaluated. The results represent a basis for the design and the implementation of a monitoring network.

Another focus was the realization of information events and training workshops in order to enable the MoE to operate the monitoring network independently. In this frame, technical staff of the MoE has been introduced into operation and maintenance of technical equipments as well as its application for collecting water quality and quantity data (capacity building). Based on results and outcomes of this study, guidelines and recommendations have been established and discussed with the local administration as well as local citizens.

Results:
The results of this study demonstrate that contaminated seepage water locally already infiltrates into the underlying quaternary river sediments as well as percolates superficially into the rivers Mailuu-Say and Kulmin-Say. The calciferous host rock and the given geochemical conditions facilitate transport processes of dissolved uranium in form of mobile Uranyl-Carbonate complexes. A downstream migration of pollutants is already indicated in both, in river water as well as in groundwater of the quaternary river sediments.

Groundwater sampling together with counterpartGroundwater sampling Source: BGR

Data about the deeper artesian aquifers and their hydraulic interaction with the shallow quaternary aquifer are very limited. The compositions of solutes in deep groundwater indicate a significant hydrothermal impact. Nevertheless, if the deeper aquifers due their contact with abandoned mines represent another Uranium source, still remains unclear.

In frame of this project, representatives of local authorities and local citizens have been informed about the potential health risks derived from the utilization of local water resources as well as some practical mitigation measures. A booklet containing the summarized results has been handed over to the participants. Furthermore, major outcomes have been distributed nationwide in frame of a press conference.

Generally, local authorities are strongly recommended to continue observation and monitoring of the identified contamination sources as well as local surface and groundwater bodies. The affected citizens should get access to these monitoring results in order to response accordingly. Furthermore, it is recommended to reconstruct and modernize the central water supply and to extend it also to southern areas of Mailuu-Suu.

Project partners:

  • Ministry of Emergency Situations of the Kyrgyz Republic (MoE)
  • Center for Radiation Protection and Radioecology, University Hannover (ZSR)

Literature:

Contact 1:

    
Prof. Dr. Thomas Himmelsbach
Phone: +49-(0)511-643-3794
Fax: +49-(0)511-643-2304

Contact 2:

    
Dr. Frank Wagner
Phone: +49-(0)511-643-2376

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