НАУКА, НОВЫЕ ТЕХНОЛОГИИ И ИННОВАЦИИ КЫРГЫЗСТАНА, №3, 2018

The research was conducted during the last 3 years under PEER-project 454. The Kumtor gold deposit was explored in the latter quarter of the last century. In 1994, the construction of the gold-rudnik began, in 1997, commercial production of gold started, in 1998, the first million ounces of gold were melted, in 2002, gold production at Kumtor exceeded 100 tons (3.2 million ounces), and currently, the pace of its extraction continues to increase. The Kumtor gold-rudnik is the largest gold-extracting enterprise in Central Asia, managed by the Canadian company Centerra Gold Inc. The gold-extracting complex is located in close proximity to glaciers, and part of the ore body is located under glaciers. For safe access to ore and protection of the open pit from flooding with meltwater, ice is removed to adjacent glacier dumps. Waste rock and ice are stored separately in the valleys of the Lysy (Lysy Glacier), Chon Sary-Tor (Davydova Glacier), and Kichi Sary-Tor (Sary-Tor Glacier) rivers (Fig. 1-4). Since 2014, a long-term program of monitoring glaciers and hydro-meteorological conditions of the Kumtor river basin has been initiated by employees of the Institute of Water Problems and Hydroenergy of the National Academy of Sciences of the Kyrgyz Republic, with the involvement of glaciologists from the Moscow State University named after Lomonosov (Russia). The objects of study were ice and water flowing from glaciers surrounding the Kumtor gold deposit. The area of the deposit includes part of the Davydova, Lysy, and Sary-Tor glaciers (Fig. 1). In close proximity are the Sary-Chat, Petrov, and Borod glaciers. On the territory of the deposit, the Kumtor river is formed, flowing out of Petrov Lake, located at the tongue of the same glacier. The Kumtor river is one of the sources of the Naryn-Syrdarya basin. The research method involved collecting 1-2 liters of meltwater from different points of the deposit. Uranium was extracted from the water using a previously developed method [2-10], and its radiochemical purification was performed to remove other interfering elements and radionuclides. The isotope composition of uranium was determined on an alpha-spectrometer with high resolution "Alpha-analyst" (Canberra) with Genie-2000 software [3-5]. The measurement time for each sample depended on the alpha-activity of the obtained preparations and ranged from tens of hours to achieve 5-15% accuracy. The results of the research on the isotope composition of uranium in ice and water of the Kumtor gold deposit are presented in the table. The first 7 samples showed minimum concentrations of uranium (not exceeding 0.2 ppb) with equilibrium isotope ratios 234U/238U. These samples characterized the isotope composition of uranium in atmospheric precipitation in the region [3-8].