Main Fan Research Articles

Theoretical knowledge enhanced genetic algorithm for mine ventilation system optimization considering main fan adjustment

Mining safety heavily depends on ventilation, which constitutes a significant portion of the energy costs in operations. Optimizing mine ventilation systems (MVSO) is crucial for minimizing this energy expenditure. However, current algorithms encounter challenges when applied to large-scale mines, primarily due to the complexity of variables and limited attention to optimizing main fans. This study introduces a theoretical knowledge enhanced genetic algorithm for MVSO, incorporating main fan adjustments. The algorithm models changes in the main fan’s operational status and integrates ventilation network equivalent simplification (VNES) and the minimum spanning tree (MST) to reduce the number of variables in the mine ventilation network. Additionally, leveraging mine ventilation sensitivity theory (MVST) enhances the quality of the initial algorithmic population. A simple case and two engineering cases collectively validated that the algorithm consistently provides effective and reliable optimization solutions for mine ventilation systems across varying scales. Specifically, the algorithm reduced energy consumption from 326.94 to 186.99 kW, 433.14 to 239.48 kW, and 520.53 to 324.90 kW across three different scales of mine ventilation systems. Comparative analysis with four other algorithms shows that, although this algorithm has a longer runtime due to the need to identify the minimum spanning tree during iterations, its ability to reduce problem dimensionality and improve population quality results in more stable and superior convergence performance, especially for large-scale mine ventilation systems.Graphical abstract

Smoke control and temperature distribution of tunnel fires under longitudinal ventilation combined with shaft exhaust

Longitudinal segmental smoke exhaust is often used for fire tunnels longer than 5 km. With the combined effect of longitudinal ventilation in the main tunnel and fan suction in the exhaust shaft, the smoke exhaust path is different from that of a traditional single-tube tunnel. Findings reported in the literature is insufficient to support the rapid development of extra-long road tunnels. In this paper, a numerical model was established by FDS (Fire Dynamics Simulator), and a 1:15 model test platform was built for verification. The effects of different longitudinal velocities, exhaust velocities, bifurcation angles, and exhaust shaft slopes on tunnel fires were analyzed for the longitudinal ventilation combined with shaft exhaust smoke evacuation mode (LVSE). The results show that when the exhaust velocity is greater than 4.5m/s, increasing the exhaust velocity has a limited effect on reducing the smoke length downstream of the exhaust shaft. The bifurcation angle has a significant effect on the velocity distribution in the ventilation shaft and the main tunnel. When the bifurcation angle is less than 45°, the airflow in the main tunnel is more likely to enter the exhaust shaft, and the velocity in the exhaust shaft is more than 5m/s. It is more favorable to reduce the smoke length when the slope of the exhaust shaft is not less than 7%. The high-temperature flue gas collects and forms a vortex near the vent under the LVSE mode, which makes the temperature decay rate slower than that when only longitudinal ventilation is used. The temperature decay model for the LVSE mode is obtained. This study is intended to provide a reference basis for the fire safety design of extra-long road tunnels under the LVSE mode.

Optimization Method of Mine Ventilation Network Regulation Based on Mixed-Integer Nonlinear Programming

Mine ventilation is crucial for ensuring safe production in mines, as it is integral to the entire underground mining process. This study addresses the issues of high energy consumption, regulation difficulties, and unreasonable regulation schemes in mine ventilation systems. To this end, we construct an optimization model for mine ventilation network regulation using mixed-integer nonlinear programming (MINLP), focusing on objectives such as minimizing energy consumption, optimal regulation locations and modes, and minimizing the number of regulators. We analyze the construction methods of the mathematical optimization model for both selected and unselected fans. To handle high-order terms in the MINLP model, we propose a variable discretization strategy that introduces 0-1 binary variables to discretize fan branches’ air quantity and frequency regulation ratios. This transformation converts high-order terms in the constraints of fan frequency regulation into quadratic terms, making the model suitable for solvers based on globally accurate algorithms. Example analysis demonstrate that the proposed method can find the optimal solution in all cases, confirming its effectiveness. Finally, we apply the optimization method of ventilation network regulation based on MINLP to a coal mine ventilation network. The results indicate that the power of the main fan after frequency regulation is 71.84 kW, achieving a significant energy savings rate of 65.60% compared to before optimization power levels. Notably, ventilation network can be regulated without adding new regulators, thereby reducing management and maintenance costs. This optimization method provides a solid foundation for the implementation of intelligent ventilation systems.

Power consumption profiles of the main fans at coal mines

Purpose. To determine the main indicators of the power consumption profiles of the main ventilation fans of coal mines under the condition of regulating their performance using controlled electric drive systems based on semiconductor elements. The methods. The methods of operations research were used to analyse technological processes in terms of compliance of the actual power consumption profiles of the main fans with their expected operating modes. The methods of mathematical statistics were used to determine the statistical parameters of the electrical loading diagrams of the main ventilation fans of coal mines. Findings. A statistical analysis of typical power consumption profiles of the main fans of coal mines with different electric drive systems has been carried out: a synchronous motor with a high-voltage frequency converter, an induction motor based on the asynchronous-thyristor cascade system, and a synchronous motor with ‘classical’ rotor excitation control without semiconductor elements. The feasibility of using adjustable electric drive systems to control the performance of main ventilation fans in terms of reducing active power consumption has been confirmed. However, at the same time, the consumption of a significant amount of reactive power is shown, which is inherent for systems based on semiconductor elements, regardless of the motor type (synchronous or asynchronous). Originality. The statistical analysis of the actual daily power consumption profiles of the main fans of coal mines with different controlled electric drive systems has shown that the standard deviation of the active load does not exceed 1% of the rated power of the drive motor and does not depend on its type (synchronous or asynchronous). Practical implementation. The practical value of the work is in determining the actual consumption of reactive power by the systems of controlled electric drive based on semiconductor elements. It shows its significant level, which should be provided by appropriate filter-compensating devices on the power supply buses of the motors of the main ventilation fans.

Numerical and experimental study of the conical connection of the blade of a rotary machine

The paper presents an experimental and numerical study of the tapered socket of the aluminum blade root of the mine main ventilation fan, which is based on the tests of a simplified full-scale model with a discarded airfoil and its subsequent finite element analysis. The calculation model takes into account elastoplastic properties of materials and non-linear contacts with friction. The proposed joint consists of an aluminum tapered blade root, two steel retainers with similar tapered surfaces, and two steel bolts that join the retainers around the root. Pre-tightening the bolts allows fixing the blade in an unloaded state in the socket and prevents its unwanted turns. Such a tightening is taken into account in the finite element analysis by means of determining, in compliance with special rules, the axial force of the pretension of the bolts. With the help of a hydraulic press acting on the lower surface of the airfoil root, the effect of the centrifugal load on the conical joint from the side of the blade airfoil is simulated. Nonlinear static analysis of the elastoplastic behavior of the structure allows determining the destructive loads that cause the bolts to break with the subsequent disconnection of the fasteners and the blade to fly out of the seat. The graphs of the equivalent von Mises stresses indicate that the maximum stresses are reached in the working part of the bolts, which fully corresponds to the nature of the destruction of the structure upon reaching the maximum equivalent load on it. The experimental study confirms the correctness of the determination of contact stresses at the tapered socket location. Correspondence of the results of the static analysis with the results of the full-scale experiment makes it possible to draw a conclusion about the correctness of the conducted finite element modelling. This allows using the developed formulation of the problem to determine the strength of rotor structures with conical connections of blades without performing preliminary experimental studies. In addition, the developed technique can be extended to a larger range of conical and cylindrical joints due to the simplicity of the approach and the versatility of the formulation of the nonlinear finite-element problem which models structures with preloaded or tensioned elements.

Interlevel Connections as a Way to Increase the Ventilation Efficiency of a Mine Ventilation Network - a Case Study

The exploitation of the deposit necessitates continuous optimisation of the ventilation network, as well as the need to change fans. One way of optimising the network and increasing the efficiency of ventilation may be to make interlevel connections in the form of large-diameter openings. In this study, simulation calculations were carried out by assuming the drilling of large-diameter holes and the selection of parameters for the main ventilation fans. An evaluation of the ventilation network was carried out by checking the validity of the simulation data with the actual data. The ventilation calculations showed that it is possible to increase the ventilation efficiency through the aforementioned method. The results of the calculations are presented with tabular data and simplified ventilation diagrams. The creation of at least one large-diameter opening and the upgrading of the main ventilation fans will ensure a minimum of proper functioning of the ventilation system. The drilling of a further opening will ensure that there is sufficient air in each ventilation area - an increase of 50% in the mine's air volume will be achieved.

Aerodynamic effect of mine cage movement on main fan performance

Aerodynamic effect of mine cage movement on main fan performance

G‘UJUMSOY KONI HAVO UZATISH STVOLIDA HAVO OQIMINI BOSHQARISH SAMARADORLIGINI OSHIRISHDA HAVO PARDASINI QOʻLLASH

On the extraction of gold-bearing ores in mines, the amount of air in the ventilation network of mines increases in proportion to increases in the length of excavations and deepening of the mines. The article deals with issues of managing the air flows into mines, the use of air curtains to reduce external and internal losses to the mine, and aerodynamic resistance. The work describes the use of the main fan and an optimal ventilation scheme in order to increase the efficiency of ventilation in mines with complex ventilation systems, with the view to reducing outdoor air losses in the ventilation duct and ventilation network by determining the optimal values for air flow, air flow rates, and pressure changes with ventilation parameters to ensure ways of effective control and distribution of the air flow.

О влиянии роста давления воздуха с глубиной на расчет требуемого количества воздуха в глубоких рудниках

The effect of increasing air pressure with the depth on the calculation of the required amount of air in the deep mines is analyzed in the work. It is established that with an increase in air pressure, the values of the volumetric maximum permissible concentrations of toxic and explosive gases in it decrease, while their maximum permissible mass concentrations remain unchanged. Failure to consider the decrease in volumetric maximum allowable concentrations of toxic and explosive gases with depth when calculating the required amount of air in the mines in some cases can lead to an underestimation of air flow rates in working areas and, as a result, to an excess of maximum allowable concentrations of harmful gases. To move the same volume of air, local ventilation fans at great depths need to expend more power than at the surface. Therefore, when working at depth, it is required to use local ventilation fans with electric motors of greater power. When air is supplied to a greater depth, it is compressed and the volume flow decreases. Therefore, in order to maintain the required volumes of air at depth, it is required to increase its flow rate at the main fan installation. This should be considered when calculating the required amount of air in deep mines. The results obtained in the work can be applied in the design of deep mines and the development of methods for calculating the required amount of air for them. Based on the conducted research, the method was adjusted for calculating the amount of air used at the Glubokaya mine of the Skalisty mine of the Polar Branch of PJSC MMC Norilsk Nickel.

COSTS REDUCTION OF MAIN FANS OPERATION ACCORDING TO SAFETY VENTILATION IN MINES – A CASE STUDY

Considering the various hazards present in an underground mine, safe ventilation entails maintaining a certain airflow rate in the mining workings. The air velocity, airflow rate and air composition must be regulated in a ventilation network by operation of the main fans. On the other hand, ventilation costs must be minimized. Thus, the optimal solution is when the requisite safety features are fulfilled and the power output of the fans is at a minimal yet sufficient rate. In real-world mines, it is common to have airstreams interlinking subnets of the main fans. The current restructuring of the mining sector commonly involves the connection of different mines, which leads to an increase in the number of such cases. This article presents the results of research into ventilation networks containing these kind of airstreams and introduces a new method for reducing ventilation costs. The method is based on an algorithm which allows the determination of the resistance of a stopping, the head of the fans and the air quantity for which air distribution is optimal. As a result, the total power output of the fans is at the lowest level that yields a reduction in ventilation costs. The method was applied for two theoretical examples and a practical one which was taken from a real ventilation network. In the first example, fan power output was reduced by 17.252 kW, which gave an annual reduction of 188.909 MWh, and an annual electricity cost reduction of €27014. Therefore, optimization enabled a saving of approximately 14% of the costs. In the second example, power output was reduced by 106.152 kW, which produced an annual reduction of 1162.364 MWh, and an annual electricity cost reduction of €166218. In this case, optimization allowed a reduction in costs of approximately 40%. Considering both examples, the cost reductions did not affect the safe airflow rate. For the real-world mine, the annual savings were 2343 MWh, which corresponds to approximately €335000.

Experimental study on precise control air quantity on demand by the cooperation of multiple main fans in mine

Due to the global energy crisis worsening, numerous businesses have prioritized energy conservation and consumption reduction. However, in mines with multiple main fans, the main fans' operation efficiency is low to meet the ventilation on-demand, and the ventilation system's energy consumption is very high. This paper proposes an energy-saving control strategy for ventilation on demand with multiple fans network, which can save much energy in mines. We use the circuit method to calculate the operating condition parameters required for the joint control of multiple main fans by analyzing the influence features of multiple fans' mutual disturbance. We study the advantages and shortcomings of the traditional fan control method and create control strategy expressions for multiple fans. The two-step fan control strategy uses the adjusting wheel blades' angle method to determine the high-efficiency operating angle and the modulating fan speed method for accurate air quantity control. Furthermore, the effectiveness of the control strategy in ventilation on demand and fan energy-saving are verified on the three-dimensional complex ventilation pipe network experimental platform. The research results show that, compared to the two typical fan control strategies, our control strategy can save energy by 27.74% and 26.92%, respectively. If this strategy is applied to a mine with two main fans rated power of 500 kW, it can save energy 2,429,806 kW per year, saving USD 442.69 per day or USD 161,582.1 per year. The payback period for this strategy is approximately 14.1 months. Therefore, this research can provide a promising step towards intelligent control of air quantity on-demand while indicating enormous potential for energy savings in mine ventilation systems.

Tectonic controls on the ecosystem of the Mara River basin, East Africa, from geomorphological and spectral index analysis

Abstract. Tectonic activity impacts the environment; therefore, identifying the influence of active faulting on environmental factors, such as soil development and vegetation growth patterns, is valuable in better understanding ecosystem functions. Here, we illustrate how tectonic activity and the lithology of bedrock influence temporal and spatial patterns of vegetation and soil parameters in a fault-controlled river basin. The Mara River basin lies in a region of previously unrecognised active normal faulting, dominated by the Utimbara and Isuria faults, resulting in areas of relative uplift, subsidence and tilting. Faulting leads to spatially variable erosion and soil formation rates as well as disruption and modification of drainage systems. On a small scale, steep escarpments cast shade and provide shelter. All of these factors might be expected to exert controls on ecosystem dynamics on a range of lengths and timescales. Here, we investigate tectonic controls on ecological processes in the Mara River basin using TanDEM-X and Sentinel-2 data. We use high-resolution digital elevation models (DEMs) to map the Utimbara and Isuria faults and to measure the height of the escarpments (up to 400 m) along the length of the faults. Total fault offset can be estimated by correlating Neogene phonolite lavas (thought to be 3.5–4.5 Myr old) on either side of the faults. If the age is correct, slip rates can be estimated to be on the order of 0.1 mm yr−1. Analysis of DEMs also reveals the presence of recent earthquake scarps in the hanging-wall sediments of the main faults and extensive alluvial fan formation on the hanging wall. Low mountain front sinuosity values and the presence of steep escarpments also suggest recent activity. Drainage is displaced across the fault traces, and, in one area, it is possible to map the lateral channel migration of the Mara River due to hanging-wall tilting. We used a 5-year normalised difference vegetation index (NDVI) time series, the clay mineral ratio (CMR) and a moisture stress index (MSI) to investigate spatiotemporal vegetation patterns and soil formation. Whilst lithology does exert some control, as expected, we observed that the downthrown hanging wall of the faults, especially directly adjacent to the escarpment, is consistently associated with a higher degree of vegetation, wetland formation and clay distribution. Analysis of spectral indices shows that the overall spatial pattern of vegetation cover is seasonally low in the flat plains and perennially high in the vicinity of more complex, tectonically influenced structures. The NDVI highlights several locations with permanently healthy vegetation along the escarpment which extend downslope for several kilometres. Our study shows that in the Mara River basin, active normal faulting is an important stabiliser of vegetation growth patterns, likely caused by favourable hydrological and pedological conditions along the escarpments; tectonic activity has a direct beneficial influence on ecological processes in this climatically sensitive region.

Закономерности аэрогазодинамических процессов при подземных пожарах

The issue was studied related to increasing occupational safety in underground mining of the mineral raw materials. The forms of the goaf are classified. An algorithm was developed for air distribution in emergency ventilation mode, including when the main ventilation fan is turned on after an emergency stop. The possibilities and mechanism of the fan influence at the stages of ventilation in emergency conditions was clarified. An algorithm is proposed for calculating ventilation parameters in case of emergency reversion of the ventilation jet. The methods for calculating the amount of air and the inertia of the ventilation system are presented at normal ventilation and during the transition from normal ventilation to emergency. The problem of air distribution during the transition period is solved with the representation of the air branch in the form of a node with multidirectional and limited movement of air jets. The methodology for predicting hazardous working situations is detailed based on the laws of diffusion transfer of gas components of the mine atmosphere. A new method of experimental determination of elements of the transitional period of ventilation was developed. The results are given concerning the study of the influence of the goaf on the efficiency of the fans operation and the duration of the transition process after reversing the fan in an emergency. A new idea is substantiated related to the gas situation as a fragment of a ventilation network with distributed sources of oxygen absorption and gas release. The structure of the matrix of the state of mine workings in an emergency was proposed. An algorithm for calculating ventilation modes for optimizing emergency response plans is formulated. It is shown that the establishment of the regularity of the processes of gas transfer during emergency ventilation mode allows to increase the efficiency of measures to ensure occupational safety in underground mining.

Strategy of mine ventilation control in optimal mode using fuzzy logic controllers

The issues related to improving the efficiency of automatic ventilation control systems of mines that regulate the air supply to the mine in accordance with the need are considered. During the tests of such a system in the 3RU mine of OAO Belaruskali, the shortcomings of its existing, implementation, associated with the incorrect choice of the most difficult-to-ventilate direction, were revealed. The possibilities of implementing a control strategy, in which the system automatically determines the optimal configuration of the operating modes of fans and regulators, are demonstrated. As an alternative to the implemented algorithms, it is proposed to use a fuzzy control device to account for the nonlinearity of the dependence of the input and output parameters of ventilation equipment and to set the conditions for the optimal operating mode of the system in a declarative form. To assess the effectiveness of the proposed approach, the data of simulation modeling of the current ventilation mode and the transition from one ventilation mode to another are analyzed with comparison with the actual data of the system operation. The simulation results show that the use of an upgraded control scheme for the main ventilation fan based on fuzzy logic in the implementation of automatic ventilation control systems makes it possible to eliminate the possibility of a shortage of fresh air in the regulated directions of its movement, as well as excessive power consumption of the main ventilation fan.

Reducing external air leakage at the main ventilation unit of the mine

Purpose. To increase the efficiency of mine ventilation by reducing external leaks through the ventilation shaft construction. To achieve this goal, it is necessary to solve the following tasks: - to analyse the existing methods for reducing external leaks through the ventilation shaft components; - consider the possibility of using a counteracting fan to unload the main fan from external leaks; - to establish the mutual influence of the main and counteracting fans during their joint operation; - to develop a methodology for determining the operating mode of the auxiliary fan in which external leaks are stopped in full. Methodology. To accomplish the set tasks, the analysis of the existing methods for combating external leaks in the main fan of the mine was carried out; a mathematical model was developed for controlling the ventilation modes of the main and auxiliary fans during their joint operation. Based on the mathematical model, the degree of mutual influence of the fans on each other was studied, a technique was developed for determining their mode, in which the mine jet in full volume enters the main fan, and external leaks are stopped by the auxiliary fan. Findings. A mathematical model for controlling mine ventilation and stopping external leaks in the ventilation shaft elements has been developed using the methods for planning industrial experiments; the degree of mutual influence of the fans on each other has been established; a method has been developed for determining the mode of their joint operation, in which the main fan is not loaded with external leaks. Originality. The degree of mutual influence of the main and auxiliary fans during their joint operation has been determined. The conditions are studied under which the mine jet enters the main fan, while external leaks occur to the auxiliary fan. Practical value. The studies conducted make it possible to separate external leaks from the main stream coming out from the mine, which increases the safety of work and reduces the cost of ventilating the mine.

Ventilation optimization through digital transformation

Underground mines require electricity to operate both the main surface fans and auxiliary systems, with primary ventilation systems typically accounting for approximately 40-60% of the mine's overall electricity consumption. The primary reason for this considerable expense is that most underground ventilation systems are designed for peak demand, regardless of the actual demand, which is commonly dictated by diesel equipment usage in trackless mining operations. Most platinum mines on the Great Dyke in Zimbabwe tend to operate their ventilation systems at this peak level, despite the mine's air quantity being well in excess of the 'true' ventilation needs. This is due to a lack of appropriate ventilation controls. The authors designed and installed a ventilation-on-demand system at one of the bord and pillar platinum mines to minimize the use of redundant air in underground operations. Fourth industrial revolution techniques were applied to the environmental monitoring and tracking systems thereby optimizing air quantity demands. The mine managed to reduce its annual power consumption by 23% through the implementation of manual control and time-of-day scheduling levels of the ventilation-on-demand concept. There was also a 6% productivity improvement, mainly attributable to an increased face time as a result of the significant reduction in the re-entry period following a blast. This paper introduces a novel concept of ventilation optimization through digital transformation targeting mainly room and pillar platinum mines. A system was designed, installed, and commissioned, though there is currently an ongoing optimization process to harness the full benefits such as productivity enhancement, reduced power costs, and improved worker health.

ВЛИЯНИЕ РЕЦИРКУЛЯЦИОННОГО ПРОВЕТРИВАНИЯ НА СНИЖЕНИЕ ВЫБРОСОВ ПАРНИКОВЫХ ГАЗОВ КАЛИЙНОГО РУДНИКА

The paper considers air recirculation as an event to improve energy efficiency and reduce greenhouse gas emissions by reducing the power consumption of the main ventilation fan. The results are presented based on calculations of the required amount of air and modeling of air distribution in the ventilation network of the mine in the AeroSet software package. The methodology of determining the quantitative volume of greenhouse gas emissions, followed by comparison and analysis of the data obtained, has been studied.

Reduction of the risk of selecting the emergency ventilation mode through local control of ventilation flows

The implementation of measures regarding the organization of emergency ventilation of mine is connected with various types of risks, as in other cases of the operation of high-risk enterprises. In particular, this applies to the emergency risk that arises when there is a need for the emergency evacuation of people from the mine workings, gassed with fire products (that is, the risk of their poisoning or damage due to the thermal factor) and the emergency risk that is provoked by the wrong choice and implementation of the emergency ventilation mode. Both types of risks require to reduce the use of means of ventilation - main and local ventilation fans. Provision should also be made for the use of various passive control devices. The main result of the methodological approach used today is the selection of the emergency ventilation mode, which maximally limits the gassing zone of the mine ventilation network with gaseous combustion products. At the same time, the criterion for the effectiveness of the emergency evacuation of miners should be the maximum use of non-gasified workings, which achieves the goal of managing ventilation in the event of accidents. The proposed control function, which characterizes the degree of risk of distribution of fire gases in mine workings, is the root mean square deviation of the concentration of fire gases in the controlled branches of the network from the required level of stabilization. For two control devices and two controlled areas, it is part of a three-dimensional cone, and the control region is bounded by two hyperbolas. The problem formulation looks similar when the size of the base of the regulating devices is increased . A limitation on the task is formulated, and a conclusion is made regarding the possibility of applying analog methods of dynamic programming for its solution. As such, the multi-step optimization method, the one-step optimization method, and the extreme coordinate optimization method (the last one is the most effective) are considered. The greatest efficiency of their use will be achieved with the introduction of an automated ventilation control system, which provides feedback from the means of regulation and regulatory devices. Keywords: emergency risk, aerological risk, management functionality, regulatory devices, exogenous fire.

Reliability of main fan coal mining plants

In this paper, a mathematical model for determining the reliability of ventilation plants was given and said ventilation plant was checked using a specific example for two types of fans operating in different modes due to the difference in the age of the fans. Within the framework of the paper, the principles of arrangement of ventilation systems of mines are stated, after which the mathematical model for determining the probability of reliability of ventilation systems is presented. For checking and proving the given mathematical model, coal mines in Serbia have been selected. The experimental part presents the basic characteristics of the main fan plants of active underground coal mines in Serbia, and based on the given mathematical model and collected data on downtime in the operation of the main fan plants at coal mines, the reliability of their operation is calculated. The paper confirms that the proposed method of determining the mathematical probability of reliability of ventilation systems can be used as an initial indicator of ventilation systems, where regular plant maintenance and application of this mathematical model could predict and prevent the operation of ventilation systems, and thus extend their lifespan. By processing the data on the operation of ventilation plants, the appropriate empirical dependence of the reliability parameters was obtained with the corresponding dependence, which enables application in practice.

Optimizing safe evacuation in mines: A method for selecting compensating measures based on microclimatic safety constraints during ventilation reversal

The article describes a method of selecting measures that should make life safe for people during evacuation through ventilation shafts under the influence of cold air during main fan reversal. The approach is based on the allocation of dangerous sections of the evacuation route and the application of compensatory measures to ensure a comfortable stay for miners in these areas. The need to introduce a compensatory measure for each area considered is determined by the condition that the time a miner stays in this zone is greater than the time during which the microclimatic parameters of the air reach unacceptable safety levels. A principle has been proposed for introducing the least resource-intensive and financially-intensive measures based on the actual need to remove miners from the mine in a given time. The developed method and the underlying approach are applicable to mine ventilation systems of any type.