Environmental impact of tin-tungsten deposits mining (Eastern Transbaikalia, Russia)

The relevance of this study stems from the need to assess the impact of mining activities on aquatic environments. This work aimed to identify patterns of component migration and accumulation in waters associated with abandoned tin-tungsten mines and to evaluate the environmental status of these waters. Water samples were collected from mine workings and waste rock dumps at the Dedovogorsk tungsten and Angatuy tin deposits, located in Eastern Transbaikalia, Russia. The waters are predominantly sodium-calcium bicarbonate and sulfate-bicarbonate types, with total dissolved solids (TDS) less than 200 mg/L and a neutral pH. Trace element concentrations generally range from single-digit to hundreds of micrograms per liter. Two distinct types of chemical element associations were identified: a technogenic association, reflecting the influence of mining activities, and a regional association, developing under natural conditions. The technogenic association is characterized by elevated concentrations of Co, Cu, Zn, and Cd, while the regional association exhibits accumulation of rare earth elements (REEs) and reduced concentrations of heavy metals. The environmental assessment revealed significant pollution in waters from adit drainage, the open-pit, and tailings storage facilities. Based on component concentrations, these waters were classified as areas of ecological emergency and disaster.