GEOCHEMICAL TYPES OF WATERS OF LEAD-ZINC DEPOSITS TAILINGS IN THE EASTERN TRANSBAIKALIA

The relevance of the topic is caused by the need to solve the problem of conserving the quality of water resources in the conditions mining impact. The main aim of the research is to study chemical composition of technogenic-ransformed waters in the areas of development of three lead-zinc deposits of Transbaikalia and their geochemical typification. Objects of the research are the waters of tailings of lead-zinc deposits Blagodatskoe, Akatuevskoe and Kadainskoe, located in the Eastern Transbaikalia. Methods. Concentrations of anions were measured by turbidimetric, potentiometric, colorimetric methods; cations and metals were determined by the atomicadsorption method and inductively-oupled plasma mass spectrometry (ICP-MS). To determine the equilibrium composition of secondary mineral phases the authors have used the diagrams of the stability fields of aluminosilicate minerals, plotted by the method proposed by R.M. Garrels and C.L. Christ. The results. According to the ratio of the main ions, the considered waters belong to hydro-carbonate, sulfate-hydro-carbonate, hydro-carbonate-sulfate and sulfate magnesium-calcium and calcium-magnesium chemical types. Drainage waters of lead-zinc deposits are characterized by significant excess of heavy metal contents (As, Zn, Cd, Pb, Sb, Mn, Mo, U, La, Se) over the average composition of leaching zone waters, with a maximum for arsenic more than 800 times and zinc - 200 times. The character of location of water composition points on the stability diagrams of the aluminosilicate minerals indicates their saturation with respect to clay aluminosilicates and calcite, that allows referring them to two geochemical types: silica-calcium-magnesium and siliceous carbonate-calcium, taking into account the peculiarities of their chemical composition. The change of these two types is caused by the intensity of water exchange. Typification of anomalous hydrogeochemical fields in mining regions is aimed at improving the ecological and geochemical monitoring of natural waters and can be used in developing measures to prevent pollution and purify waters.