Results of the experimental research of the heat-transfer jet pressure to the rock surface during thermal reaming of the borehole

The performed analysis of scientific sources confirms the existence of a small number of publications devoted to the experimental research of the gasdynamics and plasmodynamics of jets used as a heat- transfer medium in the thermal methods of mine rocks destruction. There are almost no experimental and theoretical publications related to the multiple-jet plasmotrons research. The expediency of own experimental researches performing has been substantiated concerning the lateral inflow of heat-transfer medium high-speed jets on the borehole surface. An experimental research has been made of the interaction between the heat- transfer medium high-speed jets and the surface of the borehole imitated by the through duct. The further prospects of this work are the following: to determine the gas velocity along the lateral surface of the through duct and the value of the heating capacity coefficient from the heat-transfer medium to the lateral surface of the through duct, which imitates the rock surface in the borehole. These parameters are required for creating a mathematical model of the brittle destruction of rocks

Some important aspects of rock mechanics and geomechanics

This work considers the analysis of important aspects of rock mechanics, such as the variability of the mechanical properties of rocks under the samples testing, the continuity of the rock mass and the deformation beyond the elastic limit, which have a great influence on the accuracy and reliability when conducting geomechanical studies of the rock mass during coal mining. The main methods for solving geomechanical problems are shown

Results of the experimental research of the heat-transfer jet pressure to the rock surface during thermal reaming of the borehole

The performed analysis of scientific sources confirms the existence of a small number of publications devoted to the experimental research of the gasdynamics and plasmodynamics of jets used as a heat-transfer medium in the thermal methods of mine rocks destruction. There are almost no experimental and theoretical publications related to the multiple-jet plasmotrons research. The expediency of own experimental researches performing has been substantiated concerning the lateral inflow of heat-transfer medium high-speed jets on the borehole surface. An experimental research has been made of the interaction between the heat-transfer medium high-speed jets and the surface of the borehole imitated by the through duct. The further prospects of this work are the following: to determine the gas velocity along the lateral surface of the through duct and the value of the heating capacity coefficient from the heat-transfer medium to the lateral surface of the through duct, which imitates the rock surface in the borehole. These parameters are required for creating a mathematical model of the brittle destruction of rocks

Determination of some mining parameters of the long wall for the effective use of plough systems in the Western Donbas mines

Theoretical studies of stress strain state of rock under the extraction pillar working by mechanized complex with plough systems were conducted. As a result of studies the mining parameters of the wall face working are presented. The mining parameters include the width of coal shavings continuously removed before reaching the critical rock pressure in the face and duration of the technological pause between removal of coal shavings, that leads to “relaxation” of rock pressure in the bearing zone to a safe state for continued mining. The use of the values of these parameters during the extraction pillar working ensures efficient and no-failure operation of high-performance mechanized complexes equipped with plough systems as shown by the example of mining and geological conditions of one of the mines of the Western Donbas

Ecological mechanisms of sus scrofa population regulation in modern conditions

Wild boar population (Sus scrofa) has been growing rapidly in most countries of the world over the past decades. The invasive species has high reproduction rates and well-developed adaptive responses, which allows it to successfully expand the boundaries of its habitat, create significant economic losses to agriculture and horticulture, urban ecosystems, and threatens the loss of biological diversity and the spread of zoonotic infections. The purpose of the paper was to analyse the factors that contribute to the expansion of the Sus scrofa species in the world, to determine the ecological mechanisms of population regulation against the background of rapid anthropogenic transformation of the habitat and global climatic anomalies; to assess changes in the dynamics of population size in hunting farms of Ukraine for the period from 2010 to 2020 in the Chernihivska oblast, in particular. Conventional methods of retrospective analysis, synthesis, environmental, general biological, and epizootic research were used. The paper analyses the world experience and identifies the main factors of low effectiveness of strategies for controlling the rapidly growing population of wild boar in agroecosystems, mixed forest and urban ecosystems. Due to the unique features of forming a life strategy, the Sus scrofa species demonstrate successful development, expansion of the range of available food resources, effective use of daily diversification of ecological niches in the conditions of transformed ecosystems, etc. It is established that the reason for the inefficiency of ecological mechanisms of pressure on the population of the species in the "predator-prey" system is the absence of large predators in the forest ecosystems of Chernihivska oblast. At the same time, the absence of deterrent mechanisms in the predator-prey system ensured the manifestation of next-level mechanisms, namely, the appearance of foci of African swine fever along the forest cycle in the natural biocenoses of the region. Response – the response of populations was manifested by a rapid short-term decrease in the population of Sus scrofa, as a temporary deterrent effect with a subsequent recovery trend. The results obtained can be used in the development of practical recommendations for biological monitoring, environmental control, and the development of effective forest management measures to prevent biological safety associated with the uncontrolled distribution of Sus scrofa and African swine fever based on universal ecological mechanisms of population regulatio

Experimental study for the process of the borehole thermal reaming by means of the angular plasmatron

Full-scale experimental study of the rock spallation by means of plasma jets is carried out. The aim of the experimental study was the measurement of the thermal power of plasma, weight of the rock spalls and duration of the plasma jets influence on the borehole surface. For the weight measurement of the rock spalls VT-200 analytical balance was used. In experimental study plasma jets flow out directly into the borehole of the granite block. The borehole and nozzles parameters of the plasmatron are complied with geometrical similarity. Experimental data are processed in the form of the energy consumption dependence of the thermal reaming of the borehole from the duration of the thermal treatment of the borehole surface. The results of the study could be applied to the borehole drilling processes

Numerical model to simulate ventilation of dead-end mine working with brattice

A computational model to simulate ventilation of a dead-end mine working with line brattice has been developed. To solve fluid dynamics problem, i.e. to compute flow pattern, model of inviscid flow has been used. That allows to compute quickly air flow pattern. To simulate dust dispersion in the dead-end mine working with brattice twodimensional equation of mass transfer has been used. Numerical integration of Laplas equation for the velocity potential has been carried out using Samarski two steps difference scheme of splitting. Proposed CFD model allows quick computing of dust dispersion in the dead-end mine working with brattice. Markers (porosity technique) have been used to create the complex geometrical form of computational domain. Results of numerical experiments which had been performed on the basis of the developed CFD model have been presented