In article researched difficult hydro-geological conditions of the Jakovlevsky deposit rich iron ores on which mining going under not-drained high-pressured bottomcoal water-bearing horizon. The purpose spent monitoring is resulted. The comparative analysis of results of three cycles of a hydro-geological monitoring which has shown gradual expansion of front of an over flowing of underground waters from not-drained horizon is made. Negative consequences of such process are specified. The development features of various biological forms of a life in mine which destroy construction materials are noted. Actions for decrease in consequences of an overflowing are planned.