Mitigating the adverse environmental impact resulting from closing down of mining enterprises

Purpose is to mitigate the adverse environmental impact in the context of both territory and water resources while closing down of mining enterprises. Methods. Experiments and laboratory studies were carried out to determine a relationship between salt content and amount of common reed biomass buildup. Twelve reed tillers from a 50 m3 pond in Donetsk Region were selected for the research; water is habitat for eight of the tillers, and remaining four tillers grow at the distance of up to a meter from the water level. Water and air temperature, length of the reed stems as well as their diameters were recorded during thirty-eight weeks (i.e. March – November). The amount of suspended matters was determined when filtration residues of 50 ml sample were dried out by means of a drier with their following weighing; total salt content within the water under study was identified using a weight method while evaporating 50 ml of the filtered water sample volume and its residue drying out. Findings. A relationship between salt content and common reed biomass buildup was confirmed; moreover, temperature range was determined in the context of which the greatest biomass buildup was observed basing upon the analysis of higher water plants use to purify high-mineralized turbid water. A scheme of air-lift drainage has been improved as for the drainage water disposal in the context of mines closed down by means of a wet method; the scheme makes it possible to control temperature of water being pumped out while varying a depth of water withdrawal from a mine shaft and helping provide practically year-round bioplateau action. Originality. For the first time, optimum thermal water conditions (i.e. 12 – 22ºС) within a biopurification plant at the territory of a closed-down mine have been determined theoretically and confirmed experimentally; the conditions provide year-round 32% decrease in total salt content of water as well as 35% decrease in the amount of suspended matters. Practical implications. The obtained results are applicable to rehabilitate fertile soil layer within the disturbed territories of facilities of the closed down mining enterprises with simultaneous waste purification from salts and suspended matters.