Environmental impact of disposal of coal mining wastes on soils and plants in Rostov Oblast, Russia

Underground coal mining in Southern European Russia leads to soil cover destruction in areas directly occupied by spoil tips and rock dumps located nearby. Coal producing areas in Rostov Oblast were selected for a detailed consideration. Soil samples were taken from the uppermost horizons: a layer of 0-10 cm of spoil tips and surrounding areas, as well as from 1.5 m depth vertical soil profiles. The soil samples were analysed for mineral composition, particle-size distribution and gross contents of Cu, Zn, Pb, Ag, Sn, Mo, Ba, Co, Ni, Mn, Ti, V, Cr, Ga, P, Li, Sr, Y, Yb, Nb, Sc and Zr, using emission spectral analysis. The plant species of mining influenced areas were described. The process of Technosol formation at the waste sites was considered separately. Soils have not yet formed as a result of a self-restoration on the spoil tips aged more than 50 years and burnt-out decades ago. A vegetation cover, which emerged during this time range, practically does not support the progress of any considerable soil-forming process. The ponds formed by the flooding of burning spoil tips, do not give the possibility for the formation of soils and hardly contribute to plant growth. The surface layers of spoil tips at all stages of their development are different from the surrounding steppe soils in geochemical characteristics and mineralogical composition. The atmospheric and water inflow of material from spoil tips changes (in the cases studied - worsens) a state of steppe soils within a radius of 1 km, and leads to the increase of heavy metal content in these soils.