This article offers proposals on the geoid model grid output format to ensure convenient application of the data in investigation of geodynamic processes during underground mining. With a view to improving the national geoid model, it is proposed to use the data of the detail general coverage gravimetric survey of the area of the country. These data are obtained within a reasonable time using the airborn gravimetry technology. The research findings allow creating a set of computer programs to implement the developed procedure in terms of the experimental data processing and to prove the usability of the procedure for the preliminary modeling of the geoid for the area of the Republic of Kazakhstan.

The implemented research shows that coalbed gas content in face area is proportional to pyrite content of coal, calculated with respect to iron and sulfur contents determined on X-ray fluorescent spectrometer. These results confirm the hypothesis on methane formation in coal during recovery of carbon oxides in the presence of iron-bearing minerals, in particular, pyrite, and water, and explain different contents of methane in the same rank coals. The obtained inverse proportion between the coalbed gas content in the face area and the sorption surface of coal allows supposing that methane accumulations concentrate mainly in the "solid solution" and in the closed porosity, i.e. in the coal structure. For this reason, it is more difficult and longer to recover such methane from coal than methane accumulated in open pores and fractures, which quickly leaves coal in face area.

Results of the classical method for determining the tendency of coals to spontaneous ignition from the rate constant of oxygen sorption are compared with those obtained using the improved method of thermogravimetric analysis (TGA). To study the sorption capacity of the studied coal samples by thermogravimetric analysis, it is proposed to heat the samples at a constant heating rate of 5 degrees C/min to 300 degrees C instead of high temperatures (1000 degrees C), implying coal combustion. The chemical activity of coal samples with respect to oxygen is to be calculated from the maximum mass gain within the temperature range corresponding to oxidation. As a result of the experiment, on the basis of thermogravimetric dependences, differences were revealed in the behaviour of coal samples, prone and not prone to spontaneous ignition. In comparison with the classical V. S. Veselovsky's method of determining the tendency of coals to spontaneous ignition, the TGA method allows one to get a more complete picture of the chemical activity of coals, which affects the reliability of assigning the analyzed sample to the category of spontaneous ignition hazard.

The application of a multifractal approach to assessing the degree of coal disturbance is shown using a series of 2D model configurations of coals and scanning electron microscopy (SEM) images of coal specimen surfaces. For this, multifractal spectra, also called multifractal signatures, are used, which are suitable for a comprehensive description of the structural organization of the surface of coals with different degrees of disturbance. It is shown that maximum values of the multifractal signatures can be used to assess the degree of coal disturbance, and higher values of the parameters are obtained for coal specimens taken from more disturbed coal seams. As a result of the study, six coal disturbance classes have been identified, corresponding to the disturbance classes for model coal configurations generated for the following disturbance threshold values: 3/9, 4/9, 5/9, 6/9, 7/9 и 8/9.

Abstract—The tests of fossil coal sampled in the Pechora Basin determine the chemical oxygen absorption activity U(25), thermal stability of molecular structure (by the TGA method) and microstructural nonuniformity of coal using the complex–entropy analysis. It is found that distinguishing between coals liable and unliable to spontaneous combustion by the criterion U(25) may be wrong. The thermographic analysis and studies of thermograms in the temperature range of 130–250 °С ensures more reliable identification of coal liable to spontaneous combustion The scanning electron microscopy images (1000-fold magnification) show that the propensity to spontaneous combustion of coal depends on the orderliness of the coal microstructure, which is assumed as the key governing factor in this case.

New results are presented from experimental studies of the nonthermal effect high-power (high-voltage) nanosecond electromagnetic pulses have on the development of microdefects in rock samples. Scanning electron microscopy is used to assess microstructural modifications in samples, along with X-ray microtomography for coal. Sizes of the gaps in microcracks are measured, their structural features are analyzed, and a possible mechanism of miсrodefect formation is discussed.

During coal mining, much methane remains in face-adjacent rock mass. Using the procedure developed by the IPKON Institute, the residual gas content is determined in face areas

The author study gas content of coal seams in the face areas in mines of SUEK-Kuzbass. It is found that gas content of coal samples from newly exposed face ranges between 2.4 and 13.5 m 3 /t and makes 32–60% of natural gas content of studied seams. The coal seams with lower gas content in face area have more ordered microstructure estimated by mean of plotting entropy–structure complexity diagrams based on thousandfold enlarged digital images of coal surface. Coal seams with more chaotic structural arrangement possess both higher natural gas content and gas saturation in face area.

Carrying out industrial and economic activities in territories with the possible development and intensification of landslide deformations within their limits increases the risk of displacement of significant ground masses to nearby engineering structures, damaging them and often leading to an emergency state. In a series of model examples, an approach to assessing the stability of a dump massif in the presence of pulp-like inclusion in it is shown. The model of the array is studied by the method of smoothed particles with the subsequent determination of the conditions for the stability of the mass of the blade or possible potential destruction. The scientific and practical value of the work lies in the development of a multivariate computational approach and research on the processes of deformation of slope massifs. The proposed computer modeling approach provides researchers with a tool that helps them make scientifically sound decisions for predicting the consequences of work on dumps or tailings and assessing the critical characteristics of the developed area.

Structural factors and functions of radial distribution of atoms of different coal ranks have been calculated by X-ray diffraction analysis. This made it possible to establish that the main structural component is the clusters with graphite-like packing of atoms. The predominant size of these clusters (calculated from the peaks of small-angle X-ray scattering at 5° in CoKα-radiation) for coals with a carbon content of 83--95 % is within 2--3 nm. Fossil coal is an amorphous carbonaceous substance consisting of polymorphic modifications in the sp2- and sp3-states. According to the results obtained using Raman scattering spectroscopy, the physical properties of amorphous natural coals are strongly dependent on the ratio of sp2- and sp3-hybridization of atomic orbitals. Moreover, studies have shown that the carbon atoms of the coal matrix in the sp2-state are represented by both aromatic and aliphatic conjugated chain fragments. It was found that the degree of ordering in rank LF coals is higher than in coals of a higher stage of metamorphism. This is possible if the hydrocarbon matrix in rank LF coals can be represented as a polymer consisting of conjugated chains with periodicity. With an increase in the stage of coal metamorphism, starting with coal rank G, the transformation of the coal structure occurs with a violation of the periodicity of the conjugated fragments of the polymer matrix connecting graphite-like clusters, a decrease in their length, and an increase in randomness in their arrangement

X-ray fluorescence analysis was used to study the composition of mineral inclusions in outburst-prone coal bed. A relationship between the presence of iron-containing compounds and sulfur in coals with their tendency to gas-dynamic phenomena was revealed. It was found that coal outbursts from the Pechora and Donets basins contained several times more iron than coals from non-hazardous zones of in the same coal bed. The predominance of iron over sulfur in outburst coal relative to a stoichiometric ratio between them in pyrite and, similarly, the predominance of sulfur content in coals from the zones of bed unprone to outbursts were determined.

A process of the development of rocks discontinuous displacement, which can occur under man's impact in fractured rock massif in the gravitational field in the vicinity of steep sides of deep pits and slopes is considered. The shift of the rock mass manifests itself in the formation of a characteristic spatial structure. In this regard, the problem of finding a characteristic surface that determines the movement of collapsing rock mass in a stress-strain rock massif is very relevant. To evaluate the consequences of the behavior of the fractured slope structure on the formed shear surface, a new computational approach is proposed. The calculations carried out represent quite accurately the processes of deformation and fracture development in the vicinity of the quarries faces and edges, without specifying a priori the most probable location of the rock displacement surface appearance in the massif. It is shown that the identified line of movement is closest to the brachistochrone, which corresponds to the physics of the motion of material points in the gravitational field.

It is investigated the possibility of using so–called "complexity–entropy" diagrams for the quantitative description of the degree of coal disturbance using coal images obtained by means of scanning electron microscope (SEM). These diagrams plot structural complexity measure (vertical axis) versus entropy measure (horizontal axis) for distribution of probability given in some way on the image. In this paper, the values of both measures were calculated on the basis of the shearlet transform, and the Jensen divergence was used as the basic divergence for calculating the complexity measure. All calculations were performed for more than 140 images of coal specimens with various degrees of disturbance, obtained from the quiet zone of the seam and the outburst zone. As a result of research, it was found that two-dimensional distributions for measures of complexity and entropy in most cases are informative data sets for differentiating coals by degree of complexity. Moreover, such characteristics of these distributions as mathematical expectation and, to a less degree, mode can be used as simple quantitative descriptors of coals with various degrees of disturbance. These characteristics can be used to show the closeness of the spatial structure for the analyzed coal specimens to strictly periodic or absolutely chaotic ones. On the basis of the obtained results, conclusions about the possibility to separate coals according to the degree of their outburst hazard were done.

The applicability of calculated information entropy to quantification of coal structure nonuniformity at a microlevel is demonstrated. The calculations used digital images of coal surface from scanning electron microscopy after thousandfold increase. The calculated statistical entropy-complexity values enable comparing structural nonuniformity of coal sampled from outbursts, as well as from outburst-hazardous and outburst-nonhazardous zones. It is found that coal from outburst-hazardous zones contain areas of highly chaotic structure as against the ordered structure of coal from outburst-nonhazardous zones. Outburst coal is free from chaotic structures though its structure is less ordered than in coal from outburst-nonhazardous zones. The proposed method allows detecting the certainly outburst-nonhazardous zones in coal seams using digital images of coal samples.