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The apparatus of nonstationary thermoelasticity is used to estimate the joint and separate effects of gas pressure sorption and gravity on gas drainage and on stress state in the vicinity of underground openings. It is shown that gas flow changes the stress state of coal, and pressure in sorption essentially counteracts pressure in gravity. Ignorance of the latter fact may lead to a poorly substantiated choice of a coal gas drainage technology and to an erroneous prediction of rock strength and stability.

The experimental procedure is developed and tested on a laboratory scale and using layered samples of manmade geomaterials. Within the dual-permeability model, the procedure enables determining parameters that govern fluid flow and poroelastic deformation in fractured porous rock masses, namely, fracture permeability k₁ and mass transfer coefficient β, as well as their dependence on stresses σ. The testing procedure is proposed and implemented. In the procedure, under the stepwise increasing normal stress σ, the stationary flow rates Q₁(σ) and Q₂(σ) are measured in a quasiregular fractured porous sample at the preset pressure difference: using a standard setup (Q₁) and in closed end-face fractures (Q₂). The mathematical model of the experiment is constructed, and the analytical solution of the problem on stationary flow is obtained: pressure patterns in fractures, and stress-dependence of flow rates. The experimental data interpretation algorithm enables calculating k₁ and β by the recorded flow rates Q₁ and Q₂. It is shown that the permeability k₁ is proportional to σ ^-2, and β remains almost unchanged.

The authors analyze seismic and hydrogeological data recorded after a large-scale blast on 22 September 2021 in Lebedinsky open pit mine, Kursk Magnetic Anomaly. In blasting of four groups of blocks, the maximum values of PPV are determined at five observation points arranged at the epicentral distances of 1.7-4.9 km, as well as the amplitudes of the hydrogeological response are assessed in two observation wells in overlying rock mass. The main parameters of the blast-induced seismic effect are used to calculate maximum PPV from the earlier found relation. The divergence of the recorded and theoretical data is observed in the near field of the blast in the first group of blocks, at the reduced distances of 106-198 m/kg^1/3. In blasting in sedimentary rocks at the reduced distances of 405-512 m/kg^1/3, the difference in the wavefield is observed. The research findings can be used in drilling-and-blasting control.

The article presents the results of toothed screw crushing of coal on a laboratory scale. The samples are the marketable coal from different deposits in Russia, Kazakhstan and Kyrgyzstan. From the analysis of change in the quantity outputs of grain sizes, it is found that irrespective of the coal field location and coal grade, the use of a toothed screw crusher in coal preparation for dressing leads to no overgrinding of coal.

The new design of a powered roof support for the controlled longwall top coal caving in thick coal seams contains a special outlet and a reciprocating feeder. The introduction of such technology needs pre-testing and analysis of the outlet modes per the support units, such that to ensure the maximum allowable fill of the longwall conveyor without its overloading and dynamic phenomena. Created in Rocky DEM environment with that end in view, the simulation model takes into account the physical effect of rock mass fracture using the discrete element method, and enables variation in the design parameters and operating conditions of the powered roof support. The implemented experiments make it possible to assess the interdependence of the average velocity of coal outlet to the conveyor, the outlet gate angle and the feeder vibration frequency.

The article describes numerical modeling of sublevel stoping using the discrete element method. The study included development of a modeling procedure, creation and calibration of the numerical models, and the result analysis. The optimal design parameters of structural components of the mining system are found, which are promotive of reduced ore losses in sublevel stoping at the Khibiny apatite-nepheline deposits. Some behavioral patterns of rock mass during sublevel stoping are obtained. The mechanism of ore losses is described.

The work is aimed at the theoretical development and modeling of field experiments for a high-resolution geophysical technique of transient electromagnetic sounding in order to substantiate a permafrost monitoring technology. To select the optimal parameters of the sounding system, we established the dynamics of changes in the registered electromotive force in terms of the distance between the signal transmitter and receiver. Based on field temperature measurements at the geophysical test site and the elucidated interrelation between the electrical resistivity and temperature values, we calculated the variations in the resistivity of the near-surface loams and clay loams for the period late January - early April 2022. The dynamics of changes in the boundary between seasonally frozen and underlying rocks was traced. Using the resistivity values calculated from the measured temperatures, we carried out numerical modeling of the electromotive force amplitude to identify the dependence of the signals on the shift of the boundary due to freezing. In addition, approaches were proposed to verification of the results obtained.

In the first decades of the 21st century, the need of changing the paradigm of cryology became obvious. This changing is based on two main approaches. One of them is related to transition from considering the cryosphere as a threat for people to its interpretation as one of the key resources for environmental basis and subsistence. The second approach is based on the need to build a holistic image of the Earth’s cryosphere. Considering the Earth’s cryosphere as a complex system, consisting of cold layers of atmosphere, glaciosphere and subterranean permafrost, brings us to the need for analysis of previous terms identifying object areas that study the world of cold. Ideas about the cryosphere and cryology were formulated in 1974. Modern interpretation of the object and the subject of research was the result of many long-term disputes. Currently, the term “geocryology” remains to be used as a synonym for science of permafrost. However, while building a holistic image of the Earth’s cryosphere, it is necessary to take into account the properties and state of the entire object as a whole and create new terms and concepts that can reflect the expanding contexts of studying cryogenic processes, their ontological hierarchy, system connections, etc. In this situation, the philosophy of science is designed to become a kind of source of generation of new images, concepts, and meanings.

This paper describes the milestones in the scientific career and outreach activities of Vladimir Romanovich Alekseev, an outstanding researcher of Siberian nature. V.R. Alekseev, Professor, Doctor of Geography, Merited Scientist of the Russian Federation, is a principal researcher at the Melnikov Permafrost Institute and an honorary member of the Russian Geographical Society.

This paper describes the milestones in the scientific and pedagogical activity of one of the outstanding scientists in the field of permafrost engineering L.N. Khrustalev, Honored Inventor of the Komi ASSR, Merited Scientist of the Russian Federation, Doctor of Technical Sciences, Honored Professor of Lomonosov Moscow State University.