Uranium and Fluoride Geochemical Pathways in Ulaanbaatar and Rural Mongolia
Total Page：16
File Type：pdf, Size：1020Kb
See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/308948833 Uranium and Fluoride geochemical pathways in Ulaanbaatar and rural Mongolia Article · October 2016 CITATIONS READS 0 95 4 authors, including: Robin Francis Grayson Independent Consultant 29 PUBLICATIONS 42 CITATIONS SEE PROFILE Some of the authors of this publication are also working on these related projects: Best Available Techniques (BAT) from Placer Gold Mining - worldwide study View project Status of Amphibians in Greater Manchester Conurbation, UK : A 25-year Study of Losses and Gains View project All in-text references underlined in blue are linked to publications on ResearchGate, Available from: Robin Francis Grayson letting you access and read them immediately. Retrieved on: 12 November 2016 1 Uranium and Fluoride geochemical pathways in Ulaanbaatar and rural Mongolia Robin Grayson, Baatar Tumenbayar, Daramsenge Luvsanvandan and Amarsaikhan Lkhamsuren blue sky of Mongolia combustion of uraniferous coal photochemical smog blanketing the city uraniferous ash settling over the city uraniferous ash settling in lagoons 2 Uranium and Fluoride geochemical pathways in Ulaanbaatar and rural Mongolia Robin Graysona1, Baatar Tumenbayarb, Daramsenge Luvsanvandanc and Amarsaikhan Lkhamsurend a Independent consultant, Manchester, United Kingdom b Sans Frontiere Progres NGO, Sukhbaatar district, Ulaanbaatar, Mongolia c Academician of National Academy of Science of Mongolia d Environmental consultant, Mongolia Abstract Explanation is sought for the high uranium levels in Ulaanbaatar’s ash dumps, groundwater, construction materials and vegetation, and the high radon level in the city’s drinking water. Combustion of uranium-bearing coals is a cause, but natural sources of uranium may also be factors. Mongolian coals are important sinks for elemental enrichment by uranium and other heavy metals, and 24 Mesozoic, Permian and Carboniferous coals have U-content above 1 g/tonne. Coal ash wastes are U-enriched due to depletion of volatiles and are candidates for economic extraction of uranium and other valuable metals. Uranium in water often exceeds WHO drinking water guidelines and chronic poisoning or fatality of aquatic crustaceans is probable. The uranium concentration in some ash dumps is sufficient to envisage economic recovery through in-situ leaching. While coals and ash are ‘U-sinks’, over 2,000 soda lakes and sodic soils are ‘U-drivers’ causing thousands of square kilometres of Mongolia to have elevated uranium levels, and the cause of elevated levels of fluoride, arsenic, selenium and other elements. Soda lakes and their remarkable ecosystems merit scientific study. The uranium concentration in some soda lakes is sufficient to envisage economic recovery by mining. Sulphate-reducing alkali extremophile bacteria are capable of reducing uranium (VI) to precipitate uranium (IV) oxide (UO2) as uraninite, while nitrate-reducing alkali extremophile bacteria can dissolve the uraninite into U (VI) solution. The soda lakes’ integrity depends on large-scale removal of calcium ions, sequestrated as hundreds of millions of tonnes of Ca- carbonates locked on the undersides of gravel clasts. Calcium depletion permits leaching of fluorspar veins across vast regions, and the elevated fluoride levels of well waters causes thousands of rural children to suffer from endemic dental fluorosis. Blanket surveys for dental fluorosis are warranted in all fluorspar districts. Leaching of arsenic and mobilisation in sodic waters causes thousands of people to suffer from endemic arsenic poisoning. Environmental regulations should require coal projects to publish analyses of U, F, As, Se of coals, ash and leachates, and for all uranium projects to publish water analyses of wells in their watersheds. 1Corresponding author. Manchester, United Kingdom. E-mail address: [email protected] 3 1 Introduction Until recently Mongolia had the world’s fastest growing economy with a 17.3% rise in GDP in 2011 driven by a mining boom (World Bank, 2012). Uranium mining may commence soon, exploiting conventional uranium resources amenable to low-cost open pit mining and in situ leaching. This review focuses on unconventional uranium resources, such as surface water, groundwater, soil, coal, ash and vegetation. None are current exploration targets but this may change suddenly if new technology cuts extraction costs. Uranium is more widespread in Mongolia than hitherto realised, and this study organises fragmentary data in to predictive geochemical models able to give insight into exploration, mining, environment and health. In doing so, the study sheds light on dental fluorosis being endemic in Gobi communities, and on radon emanation in the capital city. Priorities are to explain elevated uranium levels in Ulaanbaatar’s groundwater, coal supplies, construction materials and vegetation; the high levels of radon in Ulaanbaatar’s tap- water, and the high uranium levels in some springs and soda lakes. 2 Mongolia’s uranium industry 2.1 Soviet investment In Soviet times, Mongolia enjoyed a boom in mineral exploration and mining. The boom collapsed with the fall of the Soviet system and many mines closed half-finished. Mongolia de- industrialised more completely than any other nation (Reinhert, 2003). Total economic collapse was averted by exports from two mines of strategic interest to Russia: copper/molybdenum concentrates from Erdenet and fluorspar concentrates from Bor Undor. Sufficient coal mines remained open to maintain the electricity grid and district heating essential to Ulaanbaatar – the world’s coldest capital city, the average annual mean temperature being-0.9°C and winter temperatures being often as low as 25-38°C (Batima, 2003). 2.2 Subsequent revival Deprived of Russian roubles and markets, the Mongolian uranium industry closed. To avert national collapse, the gold industry was liberalised by the Government’s Gold Program. Gold output soared when the vast archive of Soviet placer gold drilling became open-file and licences became available and cheap. Over 130 placer gold companies produced 11 tonnes of gold a year and spun out over 1,000 enterprises across all sectors (Grayson and Tumenbayar, 2005). Meanwhile the uranium industry disintegrated and largely disappeared. Its archives of once- secret reports were now public but aroused scant interest due to the low uranium price. Meanwhile Soviet reports on coal, oil, copper, molybdenum, iron ore, titanium sands, tin, zinc, fluorspar and phosphates triggered boom after boom across commodity after commodity. Inward investment soared and mineral exports climbed to record levels. Informal mining boomed, notably artisanal gold mining employing over 100,000 people (Grayson, 2007). In spite of 40 years’ effort, uranium contributes nothing to the Mongolian export trade having become a strategic asset mired in state intervention, leading to disputes and uncertainty eroding investor confidence and delaying investment. 4 2.3 Vision of nuclear power Mongolian GDP will rise further, fuelled by the world-class Oyu Tolgoi copper mine; followed by the huge Tavan Tolgoi coal mine. These will boost Government finances enabling the State policy for nuclear power to be part of Mongolia’s mix of energy self-sufficiency. Already a 300-500 kW TRIGA nuclear research reactor with 1012−13 n/cm2 s neutron flux has been selected for use “in various studies and for educational and training purposes” (Sambuu et al., 2011). The second reactor is planned to be a modular nuclear reactor to supply district heating in Ulaanbaatar. A joint design study has been completed by the Nuclear Research Centre of the National University of Mongolia and the Research Laboratory for Nuclear Reactors of the Tokyo Institute of Technology (Sambuu and Obaraa, 2012). The chosen design is a high temperature gas-cooled reactor (HTGR) with passive safety features for long core life. The reactor core is 8 metres wide and 8 metres tall, and will generate 330 MWth of power. Ulaanbaatar’s district heating is supplied by superheated steam from city-based combined heat and power plants CHP #2, 3 and 4, with CHP #5 being planned (HJI and MonEnergy Consult, 2011). All burn unwashed low quality brown coal, contributing to very poor air quality in winter (World Bank, 2012).But two-thirds of the city residents lack district heating, living in ‘ger districts’ and burn coal, wood, paper, card, plastic, tyres and waste oil. This, plus emissions from CHP #2, 3 and 4, make Ulaanbaatar the world’s most polluted capital city in winter (World Bank, 2011).The outdoor air pollution was estimated by Allen et al. (2011) to cause early deaths of 623 residents a year; a figure higher than the deaths due to suicides, murders and transport accidents. Accordingly a strong case can be made for nuclear power to replace coal for district heating. Released from its district heating role, coal can be burned at distant mine sites to generate electricity for the ‘clean air’ Ulaanbaatar. Other benefits include cutting coal trains so freeing rail slots for mineral exports; cutting industrial consumption of groundwater that is Ulaanbaatar’s only source of water; and eliminating ash that is a serious health risk contributing not only to city air pollution but also to indoor radon pollution from ash used in construction materials. However, a wider role for nuclear energy is difficult to justify, albeit offering clean energy with minimal greenhouse gas emissions. Mongolia has enormous