Computer simulations in the ventilation network of the Vulcan Mine

Maintaining safety and health conditions underground, especially where potentially explosive atmospheres are possible, depends mainly on how the ventilation system is built, applied and operated in the ventilation network. The ventilation networks of a mining unit for the exploitation of the useful mineral substance are mining works that aim to ensure optimal microclimate conditions in the underground. An ventilation network is built of nodes and branches, in order to establish its structure. In order to establish the optimal air flows at branch level, specialized programs are used, with the help of which the modeling, solving and optimization of the ventilation networks can be performed. Optimizing the management of the ventilation system involves in-depth and complex analyzes on the ventilation network that require a huge volume of data that can be processed only with the help of computing technology. The paper presents an analysis of the ventilation network of the Vulcan mine using the calculation technique to simulate situations that may occur in the ventilation system.

Restructuring Simulation of the Ventilation Network

Worldwide, the demand for raw materials and materials is constantly increasing, being proportional to the growth of the population. In this sense, the demand and production of solid fuels such as coal has grown steadily. At the level of the European Union, due to the restrictive coal extraction policy, production has steadily decreased and coal-producing countries have had to implement closure programs with strict deadlines. As mining networks shrink, there is an intensification of risk factors due to changes in the ventilation system. The paper presents the restructuring of a complex ventilation network.

Ventilation Design Modeling and Optimization for an Underground Bauxite Mine

Underground bauxite mining exploitation is a challenging environment for ventilation. In this paper, such a complex underground ventilation network is modeled in detail using the Ventsim software. The network and its characteristics are selected and developed through the software, followed by their calibration and validation against actual measurements of both airflow quantity and quality which have been carried out at the mine site. This model constitutes the base of the new ventilation design for the future mine expansion. The recommendations and the characteristics for the optimization of the new proposed design are finally presented in detail.

Defining of the required parameters of the main fans on the ventilation shaft for the target model of the hard coal mine Y in connection with its decommissioning

The article presents the results of the analysis and calculations of the ventilation network of the decommissioned hard coal mine Y for the model of its target operation. After the end of hard coal mining and the liquidation of most of the mining excavations, the former Y hard coal mine will become an element of the drainage system and a protection for other, still active mining plants. In order for the Y excavation to be transformed into a mine water pumping station, its ventilation system should be rebuilt, and new parameters of the main fan should be determined for a smaller network of mining excavations. For this purpose, using the AERO-2016D program by POK “Zachód” Spółka z o.o., the parameters of the ventilation network were simulated in the target model of mine Y after the liquidation of the “Southern” shaft and mining excavations at levels 530m and 660m. The results of the simulation made it possible to select the optimal main fans for the target model of the transformed mine Y.

Impacts of increasing the airflow rate on load-haul-dump heat spread at an underground mine

In the mining process, mining companies use various mining equipment to extract valuable materials. One of them is a load-haul-dump (LHD) machine. Although this equipment is very helpful in the production process, it also has drawbacks. This equipment emits heat that can affect air temperature in the mine tunnel and cause a decrease in the comfort of mineworkers, which then impacts the mine productivity. One of the methods that can be carried out to overcome this problem is to increase the amount of airflow by changing the ventilation network. Therefore, this study aims to determine the impacts of increasing airflow on the heat spread of the operated LHD machines. The results of this study are to provide a method for reduced temperature visually and can be used as a recommendation for temperature reduction in the future. To examine the heat spreading, the researchers applied a tunnel model made using CFD software that is ANSYS Fluent and use VentSim software to simulate the network changes. The results indicated that the increase of the airflow rate could reduce the temperature on the work front when the LHD machines are operating and can affect the heat spread.

Technology for the soft implementing a digital twin into the IoT HVAC control loop

The development of application software for cyber-physical systems of buildings involves the widespread use of Internet of Things (IoT) integration platforms. In practice, the flexible functionality of IoT platforms often leads to additional costs for software enhancement of existing and connection of new units, in particular digital twins. The paper proposes a technological solution for the implementation of a digital twin of the ventilation process in the IoT control loop of heating, ventilation and air conditioning (HVAC) systems for buildings and industrial facilities. The implementation and execution of the digital twin in the form of a dynamic simulation model in the object-oriented modelling language Modelica in the OpenModelica environment is considered. The IoT platform InfluxData, based on the TICK stack, is considered as an example of an integration environment. It is a horizontally-oriented IoT platform that contains the mechanism for collecting data from devices and the InfluxDB time-series database for storing metrics. To integrate simulation models on Modelica with InfluxDB, an OMPython server is proposed. In this case, the integration scripts are executed in the Python language, which as a result extends the traditional capabilities of the IoT platform significantly to the level of a digitally twinned control system. This HVAC control involves adapting control loops by taking into account the dynamics of the air distribution process over the ventilation network, evaluating and compensating for process inertia. The publication was prepared within the framework of the Academic Fund Program at the HSE University in 2020–2021 (grant № 21-04-039).

Pre-incident planning of fires in underground hard rock mines: old and new risks

Fires in underground mines may pose a challenge to fire and rescue personnel where the complex environment and multiple influences of a fire are poorly considered during pre-incident planning. A better knowledge of pre-incident planning in underground mines would improve the safety of personnel. This study on pre-incident planning in underground mines applied data from experiments, inventories and design fire studies. A number of questions were considered related to information sources, fire modelling, capturing complexity and using fire scenarios. When performing fire modelling, empirical models could be used to complement other modelling tools. The study found that for modelling of spatially extensive mine sections, the use of ventilation network-based mine fire simulations could be a better option. Using an analytical toolbox, an iterative testing of plans and an ongoing planning process, the pre-planning challenges for a mine can be mitigated. The purpose of this study was to examine existing pre-incident planning and propose information sources, tools and specific actions for future plans.

Indicator assessment of the reliability of mine ventilation and degassing systems functioning

The gas emission control in the mines is operated by ventilation and degassing systems that ensure the aerological safety of the mines or minimize the aerological risks. The ventilation system of the mine and its individual sites includes a significant number of technical devices and equipment, and the air tubes are mainly mining workings, the condition of which determines the quality of the ventilation network (its capacity) and depends on a number of mining factors. Similarly, one of the most important elements of the degassing system, which includes its own chain of technological equipment, are wells, and in some cases, mining workings. Thus, mine ventilation and degassing systems cannot be attributed to purely technical systems, since they include mining elements characterized by high variability of the determining parameters. To assess their reliability, it is necessary to use various combined methods that include additional characteristics in relation to the mining component. At the same time, the reliability of technical devices that ensure the functioning of mine ventilation and degassing systems largely determines the efficiency (stability and reliability) of these systems and, consequently, affects the level of aerological risks. The described approach to assessing the reliability of ventilation and degassing systems of coal mines when analyzing aerological risks is based on the developed system of risk indicators for the methane factor and will allow determining the risk dynamics in automatic mode based on monitoring the parameters of the ventilation and degassing system state.

Influence of wind conditions and pressure the influence of atmospheric air on the reliability of mine ventilation and the human body

Статья посвящена обоснованию учета естественной тяги на эффективность и надежность проветривания рудников со сложной вентиляционной сетью при многоштольневом вскрытии месторождений полезных ископаемых. Цель работы. Показан уровень на легкие горнорабочих в условиях пониженного атмосферного давления. В статье приведены результаты исследований по влиянию метеорологических и геофизических факторов на надежность проветривания вентиляционных систем в условиях высокогорья. Показана динамика влияния ветровых потоков при штольневом вскрытии месторождений на устойчивость воздухоснабжения горных выработок и шахт в целом. Методы работы. Дается теоретические формулы по расчету естественной тяги при различных направлениях вектора скорости воздушных потоков на дневной поверхности. Приведен метод учета естественной тяги в различных уровнях барометрического давления. Результаты работы. Показан учет барометрического коэффициента при различных уровнях расположения горной выработки над уровнем моря. Показано, что без учета геофизических факторов метеоусловий местности обеспечение надежного проветривания рабочих мест рудника невозможно. Отмечено, что снижение парциального давления кислорода в альвеолах легких приводит к нарушению нормального ритма дыхательной функции организма человека. Это способствует к развитию дисфункции и ослаблению резистентности человека и к иным заболеваниям, что снижает потенциальную работоспособность и профессиональные качества трудящегося. Вводятся соответствующие корректирующие коэффициенты по нормируемой запыленности и по системе вентиляции для обеспечения надежной работы при всех отклонениях. Дается рекомендации по учету барометрического давления при нормировании вредных выделений в рудничную атмосферу. Предлагаемое решение учета давления атмосферного воздуха рекомендовано Госгортехнадзору и Государственным учреждениям санитарно-гигиенического нормирования внести в коррективы по нормированию вредных веществ в воздухе рабочей зоны с учетом барометрического коэффициента, что позволит снизит нагрузку на легкие работающих и уровень профзаболевания горняков. The paper is devoted to substantiation of consideration of natural draught on efficiency and reliability of ventilation of mines with complex ventilation network in multi-wall opening of mineral deposits. The level on lungs of miners in conditions of reduced atmospheric pressure is shown. Aim. The article presents the results of studies on the influence of meteorological and geophysical factors on the reliability of ventilation systems in high mountain conditions. It shows the dynamics of the influence of wind flows during adit opening of deposits on the stability of air supply of mine workings and mines as a whole. The theoretical formulas for calculating the natural draught at different directions of the velocity vector of air flows on the day surface are given. Methods. The method of taking into account the natural draught in different levels of barometric pressure is given. Consideration of the barometric coefficient at different levels of the location of the mine above sea level is shown. Results. It is shown that without taking into account geophysical factors of meteorological conditions of the area to ensure reliable ventilation of working places of the mine. It is noted that the decrease of the partial pressure of oxygen in the lung alveoli leads to disturbance of the normal rhythm of the respiratory function of the human body. This contributes to the development of dysfunction and weakening of human resistance and other diseases, which reduces the potential work capacity and professional qualities of the worker. Appropriate correction factors for normalized dustiness and ventilation system are introduced to ensure reliable operation under all deviations. Recommendations are given for taking into account barometric pressure when rationing harmful emissions into the mine atmosphere.The proposed solution for taking into account atmospheric air pressure is recommended to Gosgortechnadzor and State institutions of hygienic rationing to make adjustments for rationing harmful substances in working area air with regard to the barometric factor, which will reduce the burden on workers' lungs and the level of occupational diseases of miners

Experimental and CFD Simulations of the Aerosol Flow in the Air Ventilating the Underground Excavation in Terms of SARS-CoV-2 Transmission

The paper presents the results of experimental and model tests of transport of dispersed fluid droplets forming a cloud of aerosol in a stream of air ventilating a selected section of the underground excavation. The excavation selected for testing is part of the ventilation network of the Experimental Mine Barbara of the Central Mining Institute. For given environmental conditions, such as temperature, pressure, relative humidity, and velocity of air, the distribution of aerosol droplet changes in the mixture of air and water vapor along the excavation at a distance was measured at 10 m, 25 m, and 50 m from the source of its emission. The source of aerosol emission in the excavation space was a water nozzle that was located 25 m from the inlet (inlet) of the excavation. The obtained results of in situ tests were related to the results of numerical calculations using computational fluid dynamics (CFD). Numerical calculations were performed using Ansys-Fluent and Ansys-CFX software. The dimensions and geometry of the excavation under investigation are presented. The authors describe the adopted assumptions and conditions for the numerical model and discuss the results of the numerical solution.