In this paper, the geological faults in the zone of stable geodynamic and tectonic activity are studied. The purpose of the analytical research is to establish regularities of rock pressure in the hanging and foot walls of the geological fault and its influence on the state-deformed state of the rock massif. Comprehensive methodology that included analytical calculation will be implemented in the work. Taking into account the complexity of determining the stress-deformed state of the rocks, evaluation method of tension is adopted. Results of previously conducted computer modeling results are compared with analytic data. Conclusions regarding the implementation of the offered method are made on the basis of undertaken investigations. The obtained results with sufficient accuracy in practical application will allow consume coal reserves in the faulting zones.

The development of iron-ore deposits is accompanied by the excavation formation of considerable dimensions in the underground space and to ensure high technical and economic indicators of extraction, especially when developing high-grade iron ore, it is necessary to take into account the nature of the geological structure of the massif on the indicators of their dilution. It is established that when the chambers are worked out on a junction with hanging wall waste, the indices of ore dilution with the adjacent strata are 1.7 times higher than on a junction with the foot wall of the deposit. The tendencies and causes of variability of volume of extracted ore dilution with the adjacent strata in diff erent geological structure parts of the ore deposits are revealed, the ore basin across the pitch is characterized by a general evolving trend of the rock strength of the hanging wall and ore basin angle of incidence decreasing and increasing the thickness of the deposit from the northern side to the southern one. It has been established that the concentration of hanging rocks caving and extracted ore dilution indices is enhanced by changing their morphological composition, reducing the strength and stability of these rocks, reducing the ore basin angle of incidence, and increasing the ore deposit thickness. The obtained results allow us to lay the foundations for optimizing the parameters of the development system and the rational procedure for breaking up ore reserves in the chambers under the changing mining and geological conditions of fi eld development.

Purpose. Analysis of the man-made mineral formations of ore mining and smelting, fuel and energy complexes development accumulation, location and prospects amount in the Dnipropetrovsk region.Methods. Comprehensive approach, including analysis of state statistics, waste handling sites (WHSs), regional environmental report, environmental passport of the region, as well as data from other information sources is used in the work. Aerial photographs of man-made formations were obtained using the Google Earth 7.1.8 satellite program.Findings. The analysis of the main man-made mineral formations of ore mining and smelting, fuel and energy complexes accumulation in Ukraine (coal and mining industry waste heaps, tailing dumps, ash dumps, smelter slag dumps) was conducted, their amount and occupied areas were estimated. According to the densest location of man-made formations, they are divided into 4 regions: the Prydniprovsk region, the Kryvyi Rih region, the Nikopol region, the Pavlohrad region. According to information sources, the content of some valuable components in man-made formations has been established. Based on the world market prices of technogenic deposits components research, it was proposed to grade them according to the cost of valuable components. The promising directions have been proposed for the use of mineral resources in various economic sectors. It is noted that from the perspective of development of mineral and raw materials potential, the bulk formations are of interest because of their large reserves in the minimum area. But from the perspective of environmental protection and the interests of the Ukrainian people, the bulk technogenic formations occupying significant areas of agricultural land and having smaller mineral reserves are of great interest.Originality. The conception of man-made raw material mineral fund for further industrial development as an alternative to natural deposits is extended and systematized. For the first time, an integrated and detailed analysis has been performed of technogenic waste of the largest waste storage region in Ukraine, as well as the grouping has been proposed of mining and energy sector waste by density of location and by the contained components value. Practical implications.A sketch-map of the man-made objects location was drawn up and their gradation was carried out according to the preliminary prospects of their development. This will provide a more objective approach to the concept of industrial waste development and planning the strategy for the development of mineral and raw materials potential both at the state and regional levels.

To substantiate changes in stress-strain state of rock mass in the process of long-pillar mining with the help of double-unit longwalls while evaluating stress of a mine field in terms of Lvivvuhillia SE mine. Methods. Analysis of the plans of mine workings has become a basis for the evaluation of physical and geometrical parameters of a support pressure area of the double-unit stopes depending upon mining and geological as well as engineering conditions for n 7 b coal seam extraction. 3D model of the rock mass has been rendered using SolidWorks 2019 software. The geomechanical model of the rock mass is based upon the specified output data concerning actual operating schedule of 1018 and 1019 double-unit longwalls (numbers of the longwalls are changed as it has been required by the authorities of Lvivvuhillia SE) in terms of n 7 b seam and support patterns of the development mine workings in Lvivvuhillia SE mine. Each component of the support was modeled as a separate part with the relevant geotech data. Behaviour of the expansion of the rock mass stress-strain state within the selected point has been analyzed by means of sections at the specified plane. Findings. Rendering algorithm of 3D model of rock mass in terms of long-pillar mining of a coal seam using double-unit longwalls has been developed. A geomechanical model of the rock mass has been substantiated depending upon the mining and geological mode of occurrence and engineering parameters of coal mining process. Originality. Nature of the support pressure area formation in front of a stope as well as along the extraction pillar length has been analyzed. It has been identified that if stopes are within one and the same plane, interconnection of their frontal support pressure areas as well as walls of the development workings take place. In this context, adjoining entry acts as the extra destressing technogenic cavity in addition to its proper functions. Practical implications. Output data to make recommendations concerning the efficient mining parameters and methods for rock pressure control have been identified relying upon the analysis of stress-strain state of rock mass in the process of the operation of double-unit longwalls. Visualization of the principles of formation of the stress-strain state of support pressure area and evaluation of the rock mass condition have shown that the maximum reduced stresses reach 70 MPa in terms of 18 m width of the support pressure area.

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Purpose. Underground coal gasification, as a complex and technically difficult process, should be supported in many aspects by computer simulations or analytical calculations of rock mass behavior. However, little is known about the formation of stratification cavities in the roof rocks during coal seam gasification. To research the formation of stratification cavities and rocks deformations by mine pressure with the methods of calculation based on hypotheses or statistical information, a number of hypotheses are used. The main purpose is to examine the rock mass behavior and formation of stratification cavities during gasification of a thick coal seam.Methods. Analytical calculations were used as the research method for the work presented. The mathematical model of the stress-strain state of rock mass based on the theory of elasticity, resiliency, and maximum equilibrium, was developed and used in this paper.Findings. Critical analysis of geomechanical models of coal gasification together with their mathematical formulation was the result of considerations presented in this paper. Equations were derived for substantiating parameters of stratification cavities above the goaf of the underground gasifier. Subsequently, the volumes of stratification cavities depending on the length of gasification channel were calculated. The results have significant influence on gasifiers development and the final efficiency of gasification process.Originality. The research results were obtained from analytical calculations of rock mass behavior during thick coal seams gasification. The authors implemented a mathematical model based on the method suggested by professor A. Savostianov which was used in carrying out the calculations. Practical implications.The present study provides a starting point for further research and analytical calculations of rock mass behavior. The data and conclusions outlined in this paper may be useful in preliminary optimization and analysis of coal seams gasification. They can also be a point of reference for more advanced geomechanical simulations.

The present paper considers aspects of underground iron ore mining in Ukraine, in particular the level of mine production and reserves of basic ore fields. It analyzes and generalizes the practice of using cemented rockfill under difficult mining and hydrogeological conditions of the Pivdenno-Bilozerske high-grade iron ore field. The Belozersky iron ore district is the only one in Ukraine that, without any technological cycle of beneficiation, can provide both domestic and foreign consumers with high-quality raw iron ore as required by world markets. The PJSC Zaporizhzhia iron ore plant extracts iron ore from the Pivdenno-Bilozerske field with an iron content of more than 60% using the low-waste, environmentally friendly technology of backfilling the mined-out area with a hardening mixture. The peculiarities of the technology for steep deposit mining and the main processes of backfilling operations in terms of preparation, transportation, and construction of the backfill mass with its stability assessment are explained in detail in this paper. As a result of using cemented rockfill, rock mass stability is provided, a considerable part of industrial waste is disposed of in the mined-out area, and the earth’s surface subsidence within the area is prevented (in comparison with mining enterprises in other fields).