Some anthropogenic changes in the geological environment in Bulgaria

The anthropogenic factor is an equally important factor among the natural phenomena, changing the geological environment. It is displayed to a much higher extent than the natural processes in some sites as open-cast mines, quarries, aggregate quarries, tailing ponds, refuse dumps, landfills, etc. The natural environment is transformed within only a few years to such an outlook, which is impossible to acquire in the course of hundreds of years. A great part of the anthropogenic effects are analogous to the natural ones and have one and the same physical character. A corresponding technogenic analogue is correlated with each natural destructive geological process. However, the proceeding slow changes in nature in the course of hundreds and millions of years take place in a very short time – months and years, as a result of the anthropogenic impact. This impact is concentrated on relatively smaller areas compared to the general scale of the natural processes. The geological hazard in the case of technogenic processes ensues from the fast rates of their development and intensity in particular sites, when the geomorphological, hydrogeological and engineering geological conditions are drastically changed in a very short time. The so called anthropogenic relief is created, which changes radically the geological environment and redirects also the manifestation of the natural processes as the erosion, abrasion, suffusion, weathering, etc., creating at the same time new geostatic and geodynamic conditions by the changed loading in particular parts of the massif. The acting forces in the geological geological environment are redistributed and a new equilibrium is reached, when it is possible to activate processes as slow creep along the slopes with subsequent landslides. These are one of the most often displayed anthropogenic changes of the geological environment in the open-cast mine development. The stability of the newly formed slopes is always very important in the case of open-cast mine workings. Regardless of this fact, the preliminary calculations cannot always exclude landslide occurrence. There are many similar examples from the open-cast mines in "Maritsa-Iztok", "Medet", "Assarel", "Elatsite", "Pernik", "Kremikovtsi" and elsewhere.