A METHOD FOR EVALUATING THE BALANCE AND QUALITY OF GROUNDWATER AND MINE WATER IN THE SYSTEM OF HYDRAULICALLY CONNECTED MINES

Purpose. This study aims to develop and test a method for analytical evaluating the water-salt balance within a group of hydraulically connected mines. Methods. The proposed approach includes collection, systematisation, and analysis of actual data on the flow properties of rocks, mining and geological conditions of mining coal seams that influence forming the hydrodynamic regime of the mines of the Selydivska group. To evaluate the water-salt balance of the hydraulically connected mines, the balance method and the analytical relationships of the groundwater flow theory were used. Results. The water-salt balance elements for the hydraulically connected mines of the Selydivska group were calculated for three variants having reached the good conformity with available actual data on inflows and interflows between the mines. Inter-mine fluxes of total salt mass and salts were estimated as well as iron and manganese as microelements with the highest content in mine water. According to on the predictive estimate, the increase in the water level in mine no. 2 “Novogrodivska” from +130 m to +180 m will lead to an increase in the inter-mine water inflow of up to 10% to the active mine no. 1–3 “Novogrodivska” with a proportional increase in salt flux. Novelty. The method of calculating the water-salt balance of hydraulically connected mines based on the balance method in combination with the analytical relations of the groundwater flow theory has been substantiated and verified. The developed technique allows to preliminary estimate hydrogeochemical regime parameters without discretization of the flooded mine territory in comparison to sophisticated numerical models. Practical significance. The proposed technique can be used both for engineering predictions of the groundwater and surface water quality near closed mines, and for substantiation of a conceptual model for numerical analysis of the hydrogeochemical regime in the territories of former mineral extraction.