This article reveals the nature, causes, and main stages of occurrence and development of endogenous fires in coal mines. It is emphasized that one of the key tasks of fire protection specialists is the most accurate determination of the stage of oxidation and self-heating of coal. A review of existing gas analysis methods for identifying the initial and subsequent stages of endogenous fire development is conducted. Particular attention is focused on the importance of obtaining prompt reliable information on the self-heating temperature of coal and the dynamics of its change in the early stages of the process. Since self-heating zones are usually inaccessible for direct instrumental control, the main source of information is the gas analysis of air samples. The authors present the results of research on the dependence of the indicator gas content on the coal self-heating temperature. Based on the Graham criterion, the stages of thermal development of the process are predicted. Correlation dependencies between temperature and integral parameters of indicator gas concentrations are developed, allowing for a sufficient degree of reliability in determining the stages of coal self-heating and spontaneous combustion. Based on the results of the work, methodological recommendations for the prevention and warning of endogenous fires in coal mines and opencasts are proposed. They are based on the most informative and accessible signs suitable for quantitative assessment. The implementation of these recommendations will improve the level of industrial safety and reduce the risks of fires and explosions during mining operations.

This study utilizes Geographic Information Systems (GIS) to analyze soil cover in the Ayyrtau District, North Kazakhstan, focusing on soil types, degradation, and changes over the past 20 years. Chernozems, covering 45% of the area, are the most productive, while Solonetz soils (15%) present...

Researches of thermodynamic processes of oxidation, self-heating and self-ignition of coal are necessary for studying of dependence of terminal parameters on a set of the influencing factors. In practice of coal mining by the underground method cases of coal self-ignition in the mined-out spaces of production units (lavas) are frequent. In this case one of the tasks consists in determination of temperature in arbitrary point of the nubbly-porous medium of the mined-out space. Need of the solution of this difficult task is caused by the probability of emergency situations in places with the explosive concentration of methane. It is possible that for each seam and grade of coal it is necessary to develop, substantiate and accept an individual indicator for assessing the state of fire hazard. It is proposed to systematize and methodically process the results of field measurements and observations on the analyzed and investigated cases of endogenous fires in problem areas of mines in order to create basin databases for subse- quent operational decisions in emergency situations.

Purpose. To identify indicators of unaccounted-for aerodynamic connections between active mine workings and previously mined-out and isolated extraction panels and mine workings. Methods. To determine the significance of the criteria, their relative importance coefficients and weights were calculated. The research included an analysis of technical documentation and mine plans, finite element modeling of the stress-strain state of the rock mass in MATLAB, an air-pressure survey, statistical analysis of airflow rate fluctuations, and assessment of the gas balance of the extraction panel. Findings. Four criteria were identified and ranked. The weights of criteria K1, K2, K3, and K4 were 0.48, 0.26, 0.17, and 0.09, respectively. The presence of aerodynamic connections is established when the total weight of the criteria with positive results exceeds 0.5. A methodology for investigating such connections was developed. Originality. The criteria for identifying unaccounted-for aerodynamic connections in the mine ventilation network were ranked according to their weights. Practical implications. The developed methodology is intended to identify aerodynamic connections between active mine workings and previously mined-out and isolated extraction panels and mine workings.

В статье исследовано влияние изоляции выработанного пространства лавы на аэрогазовую ситуацию выемочного участка при прямоточной схеме проветривания. Цель – разработка аэродинамического способа управления вентиляцией с оптимизацией параметров изоляции для обеспечения устойчивого проветривания и безопасности ведения горных работ. На основе численного моделирования выявлены особенности распределения воздуха и выделения метана. Установлено, что повышенная воздухопроницаемость выработанного пространства и рост аэродинамического сопротивления поддерживаемых выработок вызывают локальные зоны загазирования. Обосновано, что изоляция выработанного пространства лавы со стороны поддерживаемой вентиляционной выработки является наиболее эффективным способом управления аэрогазовой ситуацией, обеспечивающим стабилизацию воздушного потока, снижение утечек и устранение зон опасного загазирования Бұл мақалада желдетудің тікелей тізбекті сызбасы кезінде аэрогазды жағдайға байланысты қазылған аймаққа лаваның оқшауланып, өңделген кеңістікке әсері зерттелді. Мақсат – тұрақты желдетуді және қауіпсіз тау-кен жұмыстарын қамтамасыз ету үшін оңтайландырылған оқшаулау параметрлері бар аэродинамикалық желдетуді басқару әдісін әзірлеу. Сандық модельдеу негізінде ауаның таралу заңдылықтары мен метан бөлінуі анықталды. Өндіріліп алынған кеңістіктің ауа өткізгіштігінің жоғарылауы және тірек қазбаларының аэродинамикалық кедергісінің артуы жергілікті газдану аймақтарын тудыратыны анықталды. Лаваның қазылған кеңістігін тірелген желдету жүйесінің жағынан оқшаулау ауа мен газ жағдайын бақылаудың ең тиімді жолы екені дәлелденген, бұл ауа ағынының бағыты мен жылдамдығын тұрақтандыруға, ауа ағып кетуін азайтуға және қауіпті газбен ластану аймақтарын іс жүзінде жоюға мүмкіндік береді The article studies the influence of isolation of the worked-out lava space on the air and gas situation in the excavation site with a direct-flow ventilation scheme. The aim is to develop an aerodynamic method of ventilation control with optimization of isolation parameters to ensure stable ventilation and safety of mining operations. Based on numerical modeling, the features of air distribution and methane emission were identified. It was found that the increased air permeability of the workedout space and the increase in aerodynamic resistance of the worked-out areas cause local gas accumulation zones. It has been substantiated that isolating the worked-out space of the longwall from the supported ventilation output is the most effective way to control the air and gas situation, allowing to stabilize the air flow, reduce air leaks, and eliminate dangerous gas accumulation zones

Purpose. To develop and validate an integrated methodology for open-pit slope stability assessment that provides a traceable transition from structural data of a fractured rock mass to Q′-GSI classification, kinematic analysis, strength parameter calibration, deterministic and probabilistic stability assessment, and quantitative evaluation of the influence of slope geometry. Methods. Structural data from a deposit in the East Kazakhstan Region were processed in Dips using Terzaghi correction for orientation bias and Fisher contour analysis. Q′ and GSI were determined from RQD, Jn, Jr, and Ja. Strength parameters were calibrated in RSData using the Hoek-Brown and Mohr-Coulomb criteria. The simplified Bishop method, the Spencer method, and the General Limit Equilibrium (GLE) method with the Morgenstern-Price interslice force function were applied in Slide2. Findings. Four dominant discontinuity sets were identified from 436 orientations, and values of Q′ = 3.67 and GSI = 55.7 were obtained. The proportion of kinematically feasible elements was 14.83-29.73% for planar sliding and 54.80% for flexural toppling. Four of the six intersection lines between the mean discontinuity sets satisfied the conditions for wedge sliding. For the 51.8 m high profile with an overall slope angle of 44°, the mean FS ranged from 0.9896 to 0.9947, while the probability of failure Pf ranged from 53.6 to 57.8%. The strongest relationship with FS was established for the internal friction angle (r = 0.9863). At a slope angle of 40°, increasing the height from 40 to 60 m increased Pf from 23.5 to 47.9%, whereas at H = 20 m, increasing the slope angle from 45 to 50° increased Pf from 23.9 to 90.0%. Originality. A unified assessment sequence is proposed that integrates structural-statistical data processing, Q′-GSI classification, kinematic analysis, local calibration using the Hoek-Brown and Mohr-Coulomb criteria, probabilistic limit equilib-rium analysis, and assessment of the influence of slope geometry. It is shown that kinematic susceptibility to structurally controlled failure mechanisms and Pf characterize different levels of risk and therefore require joint interpretation. Practical implications. The proposed methodology enables the identification of unfavourable spatial orientations and geometric scenarios, determination of the parameters requiring priority refinement, and simultaneous assessment of stability changes in terms of the factor of safety FS and probability of failure Pf.