Reclamation of Polish lignite open pits by flooding

This paper presents reclamation of post-mining lignite open pits by flooding in Poland. Besides, it provides some data on hydrogeological conditions of Polish lignite mines. Reclamation by flooding is presently used in post-mining voids in the Adamów Lignite Mine and the Konin Lignite Mine, and it is anticipated to be used in the future, in the case of large-space abandoned open pits in the Turów Lignite Mine and the Bełchatów Lignite Mine, whose volume will exceed one billion cubic meters. Pit lakes in Poland are formed deliberately as a planned part of the after-use of lignite surface mine voids and they are used as wildlife habitats, fisheries, water sports venues or other forms of amenity. In each case the mine voids are flooded by natural groundwater inflow, water pumped out from dewatering system and water from rivers and courses. In the existing and abandoned Polish lignite open pits there are favorable conditions in terms of water quality formation, so the water in pit lakes is of a good quality. However, the studies indicate a potential threat to the water quality in pit lakes, where they are recharged only by groundwater. Therefore, additional recharge the void with surface water or water pumped out from dewatering wells reduces the probable pit lakes deterioration.