CHAPTER 2 STATEMENT ON EXISTING INFORMATION Table of Contents of Chapter 2 2. STATEMENT ON EXISTING INFORMATION .....................................................................1 2.1. CHARACTERISTICS OF THE AREA ............................................................................................1 2.2. DEMOGRAPHY AND INFRASTRUCTURE ...................................................................................1 2.3. HISTORY AND MINING ACTIVITIES .........................................................................................3 2.4. GEOLOGY...............................................................................................................................7 2.4.1 Regional Geological Framework...........................................................................................7 2.4.2 Geology of the Mailuu-Suu Uranium Mining District .........................................................12 2.5. HYDROGEOLOGY..................................................................................................................14 2.6. HYDROLOGY OF MAILUU-SUU AND TRIBUTARIES ...............................................................15 2.7. CLIMATE ..............................................................................................................................19 2.8. LANDSLIDES/MUDFLOWS .....................................................................................................21 2.8.1 Previous work on the landslide problem in the Mailuu-Suu area........................................24 2.8.2 Landslides Databank............................................................................................................25 2.9. SEISMICITY ..........................................................................................................................25 2.9.1 Seismic data .........................................................................................................................26 2.9.2 Influence of Seismicity on landslides and tailings stability..................................................27 2.9.3 Seismicity in the Mailuu-Suu Region ...................................................................................28 2.9.4 Results of recent Research ...................................................................................................28 2.9.5 Maximal seismic accelerations ............................................................................................33 2.10. TAILINGS: DIMENSIONS, RADIOACTIVITY, CHEMO-PHYSICAL PARAMETERS .........................33 2.10.1 Physico-chemical characteristics of the residues ..............................................................35 2.11. DESCRIPTION OF A SELECTED NUMBER OF TAILINGS (ACCORDING TO 9, 10) ........................42 2.11.1 History and physical characteristics..................................................................................42 2.11.2 Radiological situation........................................................................................................46 2. Statement on existing information 2.1. Characteristics of the area The Mailuu-Suu District of uranium ore mining and milling is located at approximately 41.13 North latitude and 72.51 East longitude, about 60 km north-west of Jalal-Abad and about 25 km from the border with Uzbekistan. Uranium mining and milling industrial activities started 1946 and lasted until 1968. The associated deposition of tailings (residues from ore processing) and of low-grade ore and waste rocks from mining, covering an area of approximately 44 hectares and with an estimated volume of 3 million m³, was carried out in a moderate mountainous terrain and in gently sloping alluvial areas, often in close proximity to the Mailuu- Suu-, Kara Agash-, Kulmensai and Ailampa-Sai Rivers. During the time of mine and mill operations, the tailing impoundments, processing plants, underground mine workings, waste rock depositories were connected with various configurations of roads, tailing delivery pipelines, return water collection-, settling and conveyance systems. Due to the mountainous topography especially in the upper reaches of the regional drainage pattern, the rivers and adjacent areas are subject to major flood conditions, primarily during spring run-off. Therefore significant damage evidence for high water erosion potential can be observed all along the river banks. Also evidence for significant landslide activities and of slope instability and movement can easily be observed throughout the area causing damage of roads, power lines, pipelines and housing and in some cases of tailings impoundments . In several cases this has resulted in the relocation of infrastructure and population. 2.2. Demography and infrastructure The town of Mailuu-Suu (25000 inhabitants) is located in the project area in proximity to the tailing impoundments and mine waste rock depositories. Smallest distance from city limits of Mailuu-Suu to tailings or waste rock depositories from uranium mining is 300 m. Smaller settlements are located in the valleys of the Mailuu-Suu, Kara Agach and Ailampa-Sai rivers. In most cases the tailings and waste rock dumps are upstream of the communities, sometimes not more than 500 m from houses. An exception forms the settlement of Kara Agach where waste rock dumps are located in the centre of the settlement. The communication infrastructure of the district is comparatively well developed. The highway Osh - Bishkek goes through the general region. The distance between Mailuu-Suu and Bishkek is 550 km. The main road Mailuu-Suu –Madaniyat – Andijan (Uzbekistan) – Osh (130 km) starts along the valley of the Mailuu-Suu river. Along the rivers, and stream valleys loose gravel roads and a network of earth roads lead to summer pastures and grasslands. The two coalmines and the uranium mines are connected with main and automobile roads. The town of Mailuu-Suu is connected with Andijan city by an asphalt coated road. Chapter 2 pa ge 1 Water-supply The upper reaches of the Sary-Bee River (a tributary to the Mailuu-Suu River) 12 km upstream from Mailuu-Suu are used for water supply. Waters fed by glaciers and some springs are collected 3 km upstream from Sary Bee settlement and conducted downstream by 3 water pipes (diameter 350 mm). Their daily production amounts to 40 000 cbm with a maximum of 60 000 cbm. The population served is 23,000 inhabitants and that of the city itself is 17 to 18,000 These water pipes are buried for partial stretches along the right side of the Mailuu- Suu River valley and reportedly may have suffered some damage due to active slope movements and recent landslide activity. Downstream facilities for water purification with the planned production capacity 5.000 m³/day have been built and are hardly operational. However, at the present time up to 80 000 m³/day of water are fed into these plants, and therefore the quality of water purification is unsatisfactory. Reconstruction of the waste disposal plant is required. It can be said that at present, water is distributed from the river without treatment. Following excessive rainfall, it is highly charged with suspended matter and is not fit for domestic use. Since water is taken upstream from tailings, there is thus no risk to this water from radioactive contamination from the tailings. Since 1971 some wells are operating in the valley of the Mailuu-Suu river which produce uncovered underground pressure waters from zones of open fissuring. The total capacity of this water supply is 144 l/sec. Water supply of the villages Kugai and Sary Bee is realized with this water. It is also used for the need of the oil industry and the heat-electric generating plant of the electric bulb plant. These waterworks are under the jurisdiction of the electric bulb plant and are considered satisfactory . The last village served downstream is Kok-Tach where several distribution points connected to the conduct were recently installed. Before this, the residents took their water directly downstream from city rejections. In the best case, the water was used after decanting, explaining the occurrence of various diseases. Residents downstream from Kok-Tach continue to take domestic water directly from the river. A study conducted by the Hydraulic Service showed that extending the conduct downstream was financially impossible in current local economic conditions. No water for domestic or irrigation use is obtained by pumping wells in the water table of the Mailuu-Suu River. Plots of land bordering the river are irrigated by pumping its water. City gardens are watered from the conduit. Radioactive contamination of the river in the case of an accident at one of the tailings would thus affect the "drinkable" water supply (in fact already certainly not drinkable from a bacteriological standpoint) of only villages downstream from Kok-Tach and up to the border with Uzbekistan. Chapter 2 pa ge 2 The water supplies along the river in Uzbekistan, in particular at Izbaskan, the first city downstream, is not within the scope of our study and is not within our possibilities of field surveys. There are no groundwater resources confirmed by exploration in the project area. A detailed exploration programme of groundwater resources of the area was outlined by the Geological Agency of the Kyrgyz SSR (see appendix 30) in the 90-ties. Its realization however came to end with Soviet time. Thus, since sovereignty, water supply of the town of Mailuu-Suu is not actualized and inadequate. Villages located downstream