ECOLOGICAL-HYDRO-GEOMECHANICAL CONSEQUENCES OF THE FILTRATION STRUCTURE REFORMING IN THE ROCK MASSIF OF THE WESTERN DONBAS

Abstract

A study was carried out to assess the ecological-hydro-geomechanical consequences of the filtration structure reformation of the rock massif during underground coal mining, using as an example the territories of Western and Central Donbas regions. A complex of problems of the geological environment transformation during mining has been determined. They are associated with: compaction of sedimentary deposits caused by groundwater pumping out; effect of unauthorized formation of suffusion channels system with a different order and differentiated permeability that occurred in the space above the mine workings, which complicates the filtration conditions of the coal-bearing massif natural structure; increase in rock mass fracturing under the influence of horizontal alternating deformations with multiple stage-by-stage substitution of compression zones with extension zones and vice versa (in the process of mining) and generating a quasi-regular network of vertically oriented man-made reservoirs. It has been established that as a result of the groundwater intensive exploitation in the course of mine drainage and water intake activities, both single depression surfaces as well as local depression craters and water rise in various water-bearing horizons were formed. Their general changes and sizes have practically not changed in recent years, which indicates a quasi-stationary regime of groundwater and that water intake in a large area is practically compensated by natural resources. It has been reported that during the long-term period of the depression funnel formation, the groundwater contour was pulled up from the north (the area of the Orel River). Thus, in the conditions of coal mining in the mines of Western Donbass, the river does not receive feeding from the catchment area and becomes shallow. On the other hand, the "wet conservation" of mines will further reduce the revenue side of the river's water balance, since most of the water will be used for flooding. Problems with shallowing are not only experienced by Orel River but also by Samara River. In the zone of local depression fall villages Braginovka and Petropavlovka, and Shevchenko farm. It is concluded that there is a need for comprehensive monitoring of geomechanical, hydrogeological, geochemical and environmental processes both at the completion of the coal mines development and during the mine workings flooding. Such monitoring will make it possible to assess in a timely manner the nature and scale of changes of the geofiltrational and geomechanical characteristics in the rock mass, disturbed by operational work for a long time.