Acid Mine Drainage Contamination of the Ur Impoundment: Environmental Geochemistry Irina Myagkaya, Maria Gustaytis, Ivan Kirichenko, Bagai-ool Saryg-ool and Elena Lazareva E3S Web Conf., 98 (2019) 09021 Published online: 07 June 2019 DOI: 10.1051/e3sconf/20199809021