Energies

Research

16 pages, 1953 KiB

Open AccessArticle

Increasing Energy Efficiency in Well Drilling

by Tatiana N. Ivanova, Witold Biały, Aleksander I. Korshunov, Jerzy Jura, Krzysztof Kaczmarczyk and Krzysztof Turczyński

Energies 2022, 15(5), 1865; https://doi.org/10.3390/en15051865 - 3 Mar 2022

Cited by 5 | Viewed by 2800

Abstract

This article provides the results of the first attempt to substantiate the rates of energy consumption and energy savings during the well-drilling process. It is proposed to accept the electrical energy consumption rate as a planned indicator of consumption of resources in the [...] Read more.

This article provides the results of the first attempt to substantiate the rates of energy consumption and energy savings during the well-drilling process. It is proposed to accept the electrical energy consumption rate as a planned indicator of consumption of resources in the production of a unit of work of a specified quality. For a comprehensive assessment of the efficiency of use of energy resources during production of similar or substitute work, we determined specific energy consumption (designed, planned, actual), which includes direct consumption of all energy types in the production of a unit of work for basic and auxiliary production and operational needs, including from the consumption volume of mentioned resources and energy supply. Classification of consumption rates of electrical energy according to its action period and size scale has been proposed. The composition and amount of energy consumption rates during well-drilling have been described. The technological, expedition, and group rates of electricity consumption for drilling wells during design, survey, and technological work were determined. Electricity input items in drilling operations have been determined. For the first time, a set of measures to reduce energy costs during drilling is shown. The diagram developed for assessment of well performance allows prediction of technological and expedition rates of electricity consumption. Its creation, knowledge/understanding, implementation, analysis, and assessment by means of telemetry will allow evaluation of energy consumption when simulating drilling operations with varying drilling parameters. It will also provide an opportunity to select optimal technological or expedition rates of electricity consumption, taking account of drilling components at each depth: maximum drilling rate under constant weight on bit or maximum penetration. Based on the diagram, organizational and technical measures are proposed to save energy resources and reduce their consumption. The proposed measures allow saving up to 30–40% on energy costs. Full article

(This article belongs to the Special Issue The KOMTECH-IMTech 2021 Mining Technologies Future)

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11 pages, 13965 KiB

Open AccessArticle

Virtual Prototyping of the Cement Transporter Including Strength Criterion Based on Geotechnical Boundary Conditions

by Krzysztof Nieśpiałowski, Jarosław Tokarczyk, Sławomir Bartoszek, Piotr Kanty, Norbert Kurek, Andrzej Dymarek and Tomasz Dzitkowski

Energies 2022, 15(5), 1742; https://doi.org/10.3390/en15051742 - 25 Feb 2022

Viewed by 1617

Abstract

Regarding the vehicles used in civil engineering, some are manufactured in large quantities and some (especially innovative ones) are still prototypes manufactured for tests or rare use. The latter describes the case of equipment for mass mixing (mass stabilization) technology which is not [...] Read more.

Regarding the vehicles used in civil engineering, some are manufactured in large quantities and some (especially innovative ones) are still prototypes manufactured for tests or rare use. The latter describes the case of equipment for mass mixing (mass stabilization) technology which is not widely used compared to other types of geotechnical equipment. The purpose of this paper is to present a research and development project on an innovative cement transporter designed for mass mixing. Three-dimensional models and advanced finite element method (FEM) calculations are used to validate the design of the most important part of the cement transporter—the frame connecting the undercarriage and the upper carriage. The results presented in the paper confirm that the design based on the strength criterion and boundary conditions from geotechnical safety requirements can be used for designing the parts of the prototype vehicle. It is concluded that in innovative vehicle design for geotechnical purposes, the analyses may extend beyond the standard static analyses. Full article

(This article belongs to the Special Issue The KOMTECH-IMTech 2021 Mining Technologies Future)

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16 pages, 7277 KiB

Open AccessArticle

Correction Mechanism for Balancing Driving Torques in an Opencast Mining Stacker with an Induction Motor and Converter Drive System

by Mariusz Jabłoński and Piotr Borkowski

Energies 2022, 15(4), 1282; https://doi.org/10.3390/en15041282 - 10 Feb 2022

Cited by 6 | Viewed by 1776

Abstract

This article describes a correction mechanism for balancing torques in moving drives. The steering system is controlled by a programable logic controller (PLC), a field-oriented control (FOC) algorithm in the drive inverter system, Process Fieldbus (PROFIBUS), and a Decentralized Peripherals (DP) network. The [...] Read more.

This article describes a correction mechanism for balancing torques in moving drives. The steering system is controlled by a programable logic controller (PLC), a field-oriented control (FOC) algorithm in the drive inverter system, Process Fieldbus (PROFIBUS), and a Decentralized Peripherals (DP) network. The mechanism was applied in an opencast mining stacker with an induction motor and converter drive system. The mechanism was realized using SIMOLINK (Siemens Motion Link, SL) via fiber optic cables. Motor torque correction was applied in each electrical drive of the stacker machine. The main results presented in this paper were obtained directly from the machine. Selected digital control problems related to open mining stackers are discussed. Full article

(This article belongs to the Special Issue The KOMTECH-IMTech 2021 Mining Technologies Future)

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13 pages, 5113 KiB

Open AccessArticle

Designing a Monitoring System to Observe the Innovative Single-Wire and Wireless Energy Transmitting Systems in Explosive Areas of Underground Mines

by Amir Ehsan Kianfar, Mrityunjaya Sherikar, Andre Gilerson, Marcin Skora, Krzysztof Stankiewicz, Rudrajit Mitra and Elisabeth Clausen

Energies 2022, 15(2), 576; https://doi.org/10.3390/en15020576 - 13 Jan 2022

Cited by 9 | Viewed by 1989

Abstract

Suspended monorails are a common mode of transportation for materials and personnel in underground mines. The goal of the EU-funded project “Innovative High Efficiency Power System for Machines and Devices, Increasing the Level of Work Safety in Underground Mining Excavations (HEETII)” is to [...] Read more.

Suspended monorails are a common mode of transportation for materials and personnel in underground mines. The goal of the EU-funded project “Innovative High Efficiency Power System for Machines and Devices, Increasing the Level of Work Safety in Underground Mining Excavations (HEETII)” is to introduce a single-wire energy transmission system combined with a capacitive-coupling-based wireless transmission system to power the suspended tractor, along with a monitoring system that will monitor the energy network and additional environmental parameters of the mine. Additionally, the monitoring system acts as the wireless communication backbone, allowing for data transmission to surface headquarters, where the data are processed and logged in a central database. This enables operators to detect and take preemptive measures to prevent potential hazards in the mine, improving the overall efficiency of the energy transmission system. This paper describes the additional considerations required for electrical systems in underground mines with potentially explosive atmospheres, as well as the design of the energy transmission system and the monitoring system. Full article

(This article belongs to the Special Issue The KOMTECH-IMTech 2021 Mining Technologies Future)

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16 pages, 1306 KiB

Open AccessArticle

Selection of Employees for Performing Work Activities in Currently Used Ventilation Systems in Hard Coal Mining

by Aneta Grodzicka, Franciszek Plewa, Marcin Krause, Andrzej Figiel and Magdalena Rozmus

Energies 2022, 15(2), 408; https://doi.org/10.3390/en15020408 - 6 Jan 2022

Cited by 1 | Viewed by 1482

Abstract

The way in which rescue actions are carried out in a hard coal mine is conditioned by a number of factors, including the type, scale, and location of the hazard; location of employees at the danger and level of their endangerment; and the [...] Read more.

The way in which rescue actions are carried out in a hard coal mine is conditioned by a number of factors, including the type, scale, and location of the hazard; location of employees at the danger and level of their endangerment; and the ventilation system used in the impacted area. In this article, the importance and necessity to take into account a human factor, specifically the propensity for risky behavior, alongside the selection of rescuers for rescue action is pointed out. As an introduction to the key research studies presented in this article, main ventilation systems used in hard coal mines are described and three real cases of natural hazard occurrences in hard coal mines are discussed. An analysis of these events has shown that the degree of difficulty of a rescue action depends, among other aspects, on the ventilation system applied. Next, a study covering a synthetic assessment of 25 mining rescuers taking into account the ‘risky behavior’ parameter is presented. The results were interpreted considering the—described earlier—cases of hazard occurrence in coal mines and ventilation systems applied there. For the research sample, a selection of rescuers to carry out actions in particular types of ventilation systems, taking as a criterion the mark they obtained in the synthetic assessment, is proposed. Full article

(This article belongs to the Special Issue The KOMTECH-IMTech 2021 Mining Technologies Future)

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31 pages, 11809 KiB

Open AccessArticle

Validation of a Method for Measuring the Position of Pick Holders on a Robotically Assisted Mining Machine’s Working Unit

by Piotr Cheluszka and Amadeus Jagieła-Zając

Energies 2022, 15(1), 295; https://doi.org/10.3390/en15010295 - 2 Jan 2022

Cited by 5 | Viewed by 1759

Abstract

For effective mining, it is essential to ensure that the picks are positioned correctly on the working unit of a mining machine. This is due to the fact that the design of roadheader cutting heads/drums using computer-aided tools is based on the operating [...] Read more.

For effective mining, it is essential to ensure that the picks are positioned correctly on the working unit of a mining machine. This is due to the fact that the design of roadheader cutting heads/drums using computer-aided tools is based on the operating conditions of the roadheader/shearer/milling machine. The geometry of the cutting head is optimized for selected criteria by simulating the mining process using a computer. The reclaimed cutting head bodies that are utilized in production are manufactured again in the overhaul process. Ensuring that the dimensions of the cutting head bodies match the rated dimensions is labor-intensive and involves high production costs. For dimensional deviations of the cutting head bodies, it is necessary to control the position of the pick holders relative to the cutting head side surface in real time during robotic-assisted assembly. This article discusses the possibility of utilizing a stereovision system for calculating the distance between the pick holder base and the roadheader cutting head side surface at the point where the pick holder is mounted. The proposed measurement method was tested on a robotic measurement station constructed for the purpose of the study. A mathematical measurement model and procedures that allow automatic positioning of the camera system to the photographed objects, as well as acquisition and analysis of the measurement images, were developed. The proposed method was validated by using it for measuring the position of the pick holders relative to the side surface of the working unit of a mining excavating machine, focusing on its application in robotic technology. The article also includes the results observed in laboratory tests performed on the developed measurement method with an aim of determining its suitability for the metrology task under consideration. Full article

(This article belongs to the Special Issue The KOMTECH-IMTech 2021 Mining Technologies Future)

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20 pages, 5974 KiB

Open AccessArticle

Impact of the Selected Disturbing Factors on Accuracy of the Distance Measurement with the Use of Ultrasonic Transducers in a Hard Coal Mine

by Sławomir Bartoszek, Grzegorz Ćwikła, Gabriel Kost and Krzysztof Nieśpiałowski

Energies 2022, 15(1), 133; https://doi.org/10.3390/en15010133 - 24 Dec 2021

Cited by 4 | Viewed by 2290

Abstract

The article presents tests on the possibility of using ultrasonic transducers for accurate distance measurement in hard coal mines. In order to check the impact of selected disturbing factors on the measurement results, test stands were built, and then a full cycle of [...] Read more.

The article presents tests on the possibility of using ultrasonic transducers for accurate distance measurement in hard coal mines. In order to check the impact of selected disturbing factors on the measurement results, test stands were built, and then a full cycle of measurements with the use of different transducers (AR30 and AR41), which were selected and pre-tested in previous research projects, was realized. The impact of such disturbing factors as airborne dust (coal, stone, lime and mixed dust), changes in temperature and humidity on the propagation of ultrasonic waves, amplitude and measurement accuracy was investigated. The tests were preceded by theoretical analysis. It was found that the transducers selected for the tests had a sufficient accuracy and range, so they can be used in the devices planned to be designed, allowing for the determining of the location of a roadheader in hard coal mine roadways, taking into account technical and legal restrictions. It was also specified which disturbing factors should be compensated and what methods and parameters of this compensation should be used. Full article

(This article belongs to the Special Issue The KOMTECH-IMTech 2021 Mining Technologies Future)

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17 pages, 8565 KiB

Open AccessArticle

Monitoring of Roof Bolting as an Element of the Project of the Introduction of Roof Bolting in Polish Coal Mines—Case Study

by Artur Dyczko, Paweł Kamiński, Jacek Jarosz, Zbigniew Rak, Dariusz Jasiulek and Tomasz Sinka

Energies 2022, 15(1), 95; https://doi.org/10.3390/en15010095 - 23 Dec 2021

Cited by 21 | Viewed by 2777

Abstract

Roof bolting is the most popular type of support for underground mines’ workings. However, in Polish coal mines it is used only as a supplementary support. To raise the effectiveness and economic score of horizontal development works, JSW (Jastrzębska Spółka Węglowa) started a [...] Read more.

Roof bolting is the most popular type of support for underground mines’ workings. However, in Polish coal mines it is used only as a supplementary support. To raise the effectiveness and economic score of horizontal development works, JSW (Jastrzębska Spółka Węglowa) started a project to introduce the independent rock bolting support in its mines. The key element of the project is the monitoring of mine workings supported with roof bolting, as appropriate control allows one to ensure a proper level of safety. The following work presents a monitoring system for mine working supported with roof bolting applied in the project, as well as results of the measurements obtained using this system. The aim of the monitoring was to prove that independent roof bolting provides a proper level of safety and thus is applicable in conditions of Polish underground coal mines, particularly Budryk mine. It was to be proved by the evaluation of data obtained from instrumented bolts, extensometers of different type and convergence measurements. These results allowed us to verify the validity and reliability of the roof bolting in geological and mining conditions of Silesian Coal Basin. Full article

(This article belongs to the Special Issue The KOMTECH-IMTech 2021 Mining Technologies Future)

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15 pages, 10030 KiB

Open AccessArticle

Analysis of the Results from In Situ Testing of a Sensor In-Stalled on a Powered Roof Support, Developed by KOMAG, Measuring the Tip to Face Distance

by Sławomir Bartoszek, Joanna Rogala-Rojek, Dariusz Jasiulek, Jerzy Jagoda, Krzysztof Turczyński and Marek Szyguła

Energies 2021, 14(24), 8541; https://doi.org/10.3390/en14248541 - 17 Dec 2021

Cited by 2 | Viewed by 1867

Abstract

Mining in underground plants is associated with high risk. Improving work safety and increasing the productivity of longwall systems in the mining industry is a problem considering many criteria. Safety aspects concern both the crew and the machinery. The KOMAG Institute of Mining [...] Read more.

Mining in underground plants is associated with high risk. Improving work safety and increasing the productivity of longwall systems in the mining industry is a problem considering many criteria. Safety aspects concern both the crew and the machinery. The KOMAG Institute of Mining Technology designed and manufactured a geometry monitoring system based on inclinometers that meet the requirements of the ATEX directive. Monitoring of the roof support geometry is used for the prevention of loss of roof stability: roof fall or/and cave-in. The system was tested on a real object in real conditions. Full article

(This article belongs to the Special Issue The KOMTECH-IMTech 2021 Mining Technologies Future)

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13 pages, 4445 KiB

Open AccessArticle

Conceptual Control Method of Drilling Rig’s Torsional Vibrations Frequencies

by Tomasz Trawiński, Marcin Szczygieł, Bartosz Polnik and Przemysław Deja

Energies 2021, 14(24), 8403; https://doi.org/10.3390/en14248403 - 13 Dec 2021

Viewed by 1947

Abstract

This article focuses on the possibility of using an innovative drilling method for the implementation of underground works, especially where there is no physical possibility of using large working machines. Work on a model carried out under the INDIRES project is discussed. A [...] Read more.

This article focuses on the possibility of using an innovative drilling method for the implementation of underground works, especially where there is no physical possibility of using large working machines. Work on a model carried out under the INDIRES project is discussed. A design of a drilling tool equipped with the proposed technology is presented. The solution in question makes it possible to increase the efficiency of the drilling process, which is confirmed by computer simulations. Also, introductory tests of a drilling process supported by torsional vibration generated by an electromagnetic torque generator provided in the KOMAG laboratory facility show the reduction of the drilling time by almost two-fold. In our opinion, adding torsional vibration acting on the plane of a drilled wall that equals natural frequencies of the drilled material represents a promising new technology for drilling. The presented work constitutes the basis for the development of the proposed technology and allows us to conclude that the developed method will be of great interest to manufacturers of drilling machines and devices. Full article

(This article belongs to the Special Issue The KOMTECH-IMTech 2021 Mining Technologies Future)

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17 pages, 7924 KiB

Open AccessArticle

Method for Tuning the Parameters of Active Force Reducing Building Vibrations—Numerical Tests

by Andrzej Dymarek, Tomasz Dzitkowski, Krzysztof Herbuś, Piotr Ociepka, Andrzej Niedworok and Łukasz Orzech

Energies 2021, 14(24), 8293; https://doi.org/10.3390/en14248293 - 9 Dec 2021

Cited by 1 | Viewed by 1661

Abstract

The paper formulates a method of active reduction of structure vibrations in the selected resonance zones of the tested object. The method ensures reduction of vibrations of the selected resonance zones by determining the parameters of the active force that meets the desired [...] Read more.

The paper formulates a method of active reduction of structure vibrations in the selected resonance zones of the tested object. The method ensures reduction of vibrations of the selected resonance zones by determining the parameters of the active force that meets the desired dynamic properties. The paper presents a method for determining the parameters of the active force by reducing the vibrations of the structure in its resonance zones to a given vibration amplitude. For this purpose, an analytical form was formulated, which will clearly define the dynamic properties of the tested object and the force reducing the vibrations in the form of a mathematical model. The formulated mathematical model is a modified object input function, which in its form takes into account the properties of the active force reducing the vibrations. In such a case, it is possible to use the methods of mechanical synthesis to decompose the modified characteristic function into the parameters of the system and the parameters of the force being sought. In the formulated method, the desired dynamic properties of the system and the vibration reducing force were defined in such a way that the determined parameters of the active force (velocity-dependent function) had an impact on all forms of natural vibrations of the tested system. Based on the formalized method, the force reducing the vibrations of the four-story frame to the desired displacement amplitude was determined. Two cases of determining the active force reducing the vibrations to the desired vibration amplitude of the system by modifying the dynamic characteristics describing the object together with the active force were considered. For both cases, the system’s responses to the oscillation generated by harmonic force of frequencies equal to the first two forms of natural vibrations of the tested system were determined. In order to verify the determined force reducing the vibrations of the object and to create a visualization of the analyzed phenomenon, the building structure dynamics were analyzed with the use of PLM Siemens NX 12 software. The determined force parameters were implemented into the numerical model, in which the tested system was modelled, and the response time waveforms were generated with regard to the considered story. The generated waveforms were compared with the waveforms obtained in the formalized mathematical model for determining the active force reducing the vibrations. The vibrations of the tested numerical model were induced by the kinematic excitation with the maximum amplitude equal to 100 mm, which corresponds to the vibration amplitude during the earthquake with a force equal to level 5 on the Richter scale. Full article

(This article belongs to the Special Issue The KOMTECH-IMTech 2021 Mining Technologies Future)

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11 pages, 6920 KiB

Open AccessArticle

Economic Analysis of the Application of the Technological System for Removing Suspended Solids from Mine Drainage Waters

by Jolanta Gumińska, Franciszek Plewa, Aneta Grodzicka, Adam Gumiński, Magdalena Rozmus and Dariusz Michalak

Energies 2021, 14(24), 8232; https://doi.org/10.3390/en14248232 - 7 Dec 2021

Cited by 5 | Viewed by 2110

Abstract

This paper presents the results of the technological and economic analysis of mine water treatment systems before their discharge into the environment. The following analysis enabled us to determine the profitability of the investment, taking into account the TSS (total suspended solids) concentration [...] Read more.

This paper presents the results of the technological and economic analysis of mine water treatment systems before their discharge into the environment. The following analysis enabled us to determine the profitability of the investment, taking into account the TSS (total suspended solids) concentration in mine water. The simulation results showed that it is economically profitable to apply a water treatment system if natural sedimentation carried out in underground mine water passages, or in sedimentation tanks located on the ground, is ineffective for TSS removal. Economic and financial parameters allow us to conclude that all analyzed variants of the application of a pre-treatment system are characterized by high economic effectiveness. This mainly results from the high profitability of an analyzed investment, comparatively low capital expenditure, and present low market percentage rates. The most profitable variant (TSS concentration is 1000 mg/dm³) brings significant economic indicators, i.e., high NPV–Net Present Value (100 319 270.28 PLN), a high NPVR–Net Present Value Ratio (8.96 PLN/PLN), and a short discount payback period (1 year 236.6 days). A high internal rate of return (157.8%) for this variant reduces the risk of losing profitability in a situation of growing capital costs in the monetary market. Full article

(This article belongs to the Special Issue The KOMTECH-IMTech 2021 Mining Technologies Future)

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9 pages, 2341 KiB

Open AccessArticle

A Study on the Hard Coal Grindability Dependence on Selected Parameters

by Krzysztof Kogut, Vladimir Cablik, Piotr Matusiak, Daniel Kowol, Tomasz Suponik, Dawid M. Franke, Barbara Tora and Radosław Pomykała

Energies 2021, 14(23), 8158; https://doi.org/10.3390/en14238158 - 5 Dec 2021

Cited by 2 | Viewed by 2677

Abstract

A very important aspect of proper preparation of the coal mixture for the coking process is its appropriate grinding. One of the parameters describing the energy input required for grinding is the Hardgrove index. This research was undertaken to determine the dependence of [...] Read more.

A very important aspect of proper preparation of the coal mixture for the coking process is its appropriate grinding. One of the parameters describing the energy input required for grinding is the Hardgrove index. This research was undertaken to determine the dependence of the Hardgrove grindability index on selected physicochemical properties of coal. The Hardgrove grindability index was determined using the available methods described in the standards, and the dependence on selected parameters was examined. A clear positive correlation with calorific value and smaller (also positive) correlations with moisture content and free swelling index was obtained. A slight negative correlation was also obtained with sulfur content. Full article

(This article belongs to the Special Issue The KOMTECH-IMTech 2021 Mining Technologies Future)

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15 pages, 6078 KiB

Open AccessArticle

Performance of Passive and Active Balancing Systems of Lithium Batteries in Onerous Mine Environment

by Wojciech Kurpiel, Przemysław Deja, Bartosz Polnik, Marcin Skóra, Bogdan Miedziński, Marcin Habrych, Grzegorz Debita, Monika Zamłyńska and Przemysław Falkowski-Gilski

Energies 2021, 14(22), 7624; https://doi.org/10.3390/en14227624 - 15 Nov 2021

Cited by 11 | Viewed by 2678

Abstract

To use lithium-iron-phosphate battery packs in the supply systems of any electric mining equipment and/or machines, the required conditions of work safety must be met. This applies in particular to coal mines endangered by fire and/or explosion. To meet the spark-safety conditions, the [...] Read more.

To use lithium-iron-phosphate battery packs in the supply systems of any electric mining equipment and/or machines, the required conditions of work safety must be met. This applies in particular to coal mines endangered by fire and/or explosion. To meet the spark-safety conditions, the cells (together with the battery management system—BMS) must be isolated from the influence of the environment, and therefore placed in special fire-tight housings. This significantly degrades the heat dissipation, thus affecting the operating conditions of the cell-packs. Therefore, their usage without the so-called BMS is not recommended, as shown in the authors’ preliminary research. In practice, various BMS are used, most often with the so-called passive balancing. However, their application in mines is uncertain, due to the effect of heating under operation. When it comes to active BMS, they usually possess a quite complex structure and hence, are relatively expensive. Therefore, the authors conducted research for two specially developed active and one commercial passive BMS cooperating with selected lithium-iron-phosphate (LiFePO₄) batteries when used in a suspended mining vehicle type PCA-1. The tests were carried out under environmental temperatures ranging from +5 °C to +60 °C. The effect of mismatching (12.5% to 37.5% of total cells number) of the cell parameters on the temperature distribution and voltage fading at the terminals of individual cells was checked. As a result of the investigations, the practical usefulness of the developed active BMS was determined, enabling the extension of the lithium-iron-phosphate battery life under onerous mine conditions, for a single recharge, which is a novelty. On the basis of the obtained results, appropriate practical conclusions were formulated. Full article

(This article belongs to the Special Issue The KOMTECH-IMTech 2021 Mining Technologies Future)

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14 pages, 2455 KiB

Open AccessArticle

Technical and Economic Aspects of Electric Energy Storage in a Mine Shaft—Budryk Case Study

by Jarosław Kulpa, Paweł Kamiński, Kinga Stecuła, Dariusz Prostański, Piotr Matusiak, Daniel Kowol, Michał Kopacz and Piotr Olczak

Energies 2021, 14(21), 7337; https://doi.org/10.3390/en14217337 - 4 Nov 2021

Cited by 15 | Viewed by 3043

Abstract

The transformation of the energy sector towards an increased share of renewable energy sources in the energy mix requires attention in the area of electricity storage. Renewable energy sources (photovoltaics or wind energy) are marked by the intermittency of electricity production and require [...] Read more.

The transformation of the energy sector towards an increased share of renewable energy sources in the energy mix requires attention in the area of electricity storage. Renewable energy sources (photovoltaics or wind energy) are marked by the intermittency of electricity production and require the construction of energy storage to adapt the energy supply to the demand, providing greater stability. The authors focused on verifying the solution of gravitational energy storage in existing shafts of hard coal mines in Poland. The issue is significant for Poland, as a country with an extensive mining infrastructure, which is searching for new scientific and practical solutions to utilize disused mining shafts for new purposes. In the analysis, the focus was on one shaft located within the Upper Silesian Coal Basin (Górnośląskie Zagłębie Węglowe), maintained for the drainage of the neighboring deposit. The article presents the calculation of energy that can be stored and an analysis of the effectiveness of energy storage in the shaft. The basic assumption of the analysis was 1 cycle of work per day (charging and discharging) in order to use the effect of low prices at night and high prices during peak hours (according to Towarowa Giełda Energii (TGE) quotations). Although energy storage already functions around the world, the studied case is new, because it refers to the usage of existing shafts which makes it a non-investment case. The results of the study showed that the obtained economic effects of the analyzed solution are low, therefore there is no economic justification of activities related to its implementation, taking into account the current price conditions. Full article

(This article belongs to the Special Issue The KOMTECH-IMTech 2021 Mining Technologies Future)

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20 pages, 6257 KiB

Open AccessArticle

Testing the Impact of Braking Algorithm Parameters on Acceleration and Braking Distance for a Suspended Monorail with Regard to Acceptable Travel Speed in Hard Coal Mines

by Jerzy Świder, Kamil Szewerda, Krzysztof Herbuś and Jerzy Jura

Energies 2021, 14(21), 7275; https://doi.org/10.3390/en14217275 - 3 Nov 2021

Cited by 6 | Viewed by 2057

Abstract

Increasing the maximum speed limit of suspended monorails, which became a very popular means of auxiliary transport, is one of the aspects of improving the efficiency of work in underground coal mines. It is especially important to enable higher (than allowed by the [...] Read more.

Increasing the maximum speed limit of suspended monorails, which became a very popular means of auxiliary transport, is one of the aspects of improving the efficiency of work in underground coal mines. It is especially important to enable higher (than allowed by the law) travel speed, when moving the crew to and from the workplace, which is often very distant from the shaft, and can take more than one hour of travel. Increasing this speed will make it possible to extend the effective working time of miners, which should have a positive impact on the economics of the mine. However, driving at a higher speed is also associated with increased risk of a negative impact of dynamic overload to people, e.g., during emergency braking of the suspended monorail. The concept of sequential emergency braking was developed in order to avoid excessive deceleration affecting passengers and the operator of the monorail, as well as to minimize the dynamic loads acting on the rail suspensions and on the roadway support frames, which could cause serious accidents. The developed assumptions with regard to the new method of braking are innovative in the area related to hard coal mining, where there are currently no such solutions. According to the principles of the developed concept, the total braking force was divided into two stages. The activation of the second stage depends on the deceleration measured after the time delay from activation of the first stage of braking. We present the results of the numerical simulations, which aimed to analyze the impact of changing the parameters of the braking algorithm on the braking deceleration, the braking time, and the braking distance. The possibility of changing the braking force and downward emergency braking on a high inclination angle were also taken into account during the numerical simulations. Use of the developed emergency braking algorithm enables the optimization of this process at a higher speed than is currently used. This aspect is also very important in increasing the safety for people travelling at a higher speed limit. The numerical simulations provide knowledge for safety in terms of the dynamic overload during emergency braking, without injury risk to miners or damage to equipment. Full article

(This article belongs to the Special Issue The KOMTECH-IMTech 2021 Mining Technologies Future)

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15 pages, 11091 KiB

Open AccessArticle

CFD Simulations of the New Construction of Light Brattice Wall for Mine Shafts

by Tomasz Rokita, Paweł Kamiński, Hubert Ruta and Zbigniew Szkudlarek

Energies 2021, 14(21), 7239; https://doi.org/10.3390/en14217239 - 3 Nov 2021

Viewed by 2189

Abstract

Brattice walls in mine shafts are used for various purposes, for example, permanent brattice walls can be used to separate ventilation sections. They can be also used in the case of modernization of the hoisting system, as it is in Shaft no. 1 [...] Read more.

Brattice walls in mine shafts are used for various purposes, for example, permanent brattice walls can be used to separate ventilation sections. They can be also used in the case of modernization of the hoisting system, as it is in Shaft no. 1 of the Szczygłowice department, part of the Knurów-Szczyłowice coal mine. To shorten the time and reduce costs of the hoist modernization, the shaft is to be partitioned into two sections—with the hoist operating in one of them and another one being modernized in the other section. The new construction of the light brattice wall was designed for this purpose. To prove its usefulness and safety it was tested in the laboratory and computer simulations. The following paper presents CFD simulations of the brattice—its methodology and results together with an overview of works to be conducted in the shaft. Full article

(This article belongs to the Special Issue The KOMTECH-IMTech 2021 Mining Technologies Future)

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12 pages, 5390 KiB

Open AccessArticle

Influence of Operation Conditions on Temperature Hazard of Lithium-Iron-Phosphate (LiFePO₄) Cells

by Wojciech Kurpiel, Bartosz Polnik, Łukasz Orzech, Krzysztof Lesiak, Bogdan Miedziński, Marcin Habrych, Grzegorz Debita, Monika Zamłyńska and Przemysław Falkowski-Gilski

Energies 2021, 14(20), 6728; https://doi.org/10.3390/en14206728 - 15 Oct 2021

Cited by 2 | Viewed by 1826

Abstract

The article presents and discusses the results of research on hazard, especially temperature, for selected lithium-ion-phosphate cells operated in accordance with the manufacturer’s recommendations but used under onerous mining conditions. This applies to the performance of cells in battery sets without the application [...] Read more.

The article presents and discusses the results of research on hazard, especially temperature, for selected lithium-ion-phosphate cells operated in accordance with the manufacturer’s recommendations but used under onerous mining conditions. This applies to the performance of cells in battery sets without the application of any management system (BMS). On the basis of the obtained test results, first of all, the influence of the value of the charging current of cells and the ambient temperature for both free and deteriorated heat exchange, appropriate conclusions and practical recommendations were formulated. This applies especially to threats in the case of random, cyclic, minor overloading, and discharging of the cells. Full article

(This article belongs to the Special Issue The KOMTECH-IMTech 2021 Mining Technologies Future)

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15 pages, 6533 KiB

Open AccessArticle

Continuous Support for Roadways

by Krzysztof Mazurek, Marek Szyguła, Andrzej Figiel and Krzysztof Filipowicz

Energies 2021, 14(18), 5801; https://doi.org/10.3390/en14185801 - 14 Sep 2021

Cited by 5 | Viewed by 1652

Abstract

Opening deeper coal seams requires constructing underground mine roadways in difficult geological conditions. Supporting of such roadways is subjected to a very high load from the rock mass. The types of roof supports used so far do not provide immediate support for the [...] Read more.

Opening deeper coal seams requires constructing underground mine roadways in difficult geological conditions. Supporting of such roadways is subjected to a very high load from the rock mass. The types of roof supports used so far do not provide immediate support for the rock mass, which tends to converge the roadway, allowing for a rapid build-up of stresses in the surrounding rock mass. The article presents a new type of frame roadway support. This is a yielding support (consecutive arches are connected in a helical pattern), enabling the successive arches to be provided with initial load-bearing capacity already at the construction stage. The so-called unscrewing of the helix enables the arches to be pressed against the surface of the developed roadway with a controlled force. The introduction discusses the types of yielding roof supports used in the Polish mining industry and indicates their characteristic features. Further along in the article, the assumptions adopted for the construction of models to be tested and assumptions for the static and dynamic load to the models are defined, and the results of the model numerical tests are presented. The tests were aimed at comparing the qualitative behavior of the new roof support and the closed, circular support which is closest to it. The results of numerical tests confirmed the strength of the new solution not lower than the closed (circular) frame support, previously used in the most difficult geological conditions. Full article

(This article belongs to the Special Issue The KOMTECH-IMTech 2021 Mining Technologies Future)

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20 pages, 8900 KiB

Open AccessArticle

The Impact of Electricity Consumption Profile in Underground Mines to Cooperate with RES

by Sylwester Kaczmarzewski, Piotr Olczak and Maciej Sołtysik

Energies 2021, 14(18), 5775; https://doi.org/10.3390/en14185775 - 14 Sep 2021

Cited by 7 | Viewed by 2312

Abstract

In Poland, a dynamic increase in the share of renewable energy sources in the national energy mix has been observed in recent years. Until now, these were mainly installations used for the needs of single-family houses and large-scale installations used on the RES [...] Read more.

In Poland, a dynamic increase in the share of renewable energy sources in the national energy mix has been observed in recent years. Until now, these were mainly installations used for the needs of single-family houses and large-scale installations used on the RES auction market. However, due to the fact that the carbon footprint of the offered products is taken into account, this aspect is becoming more and more important. The carbon footprint can be offset by, among others, by covering the energy needs of the industrial plant by its own renewable energy sources. The article analyzes four sample electricity demand profiles of production plants operating in the mining industry, mainly located in Upper Silesia. Using statistical methods, the fitting of potential photovoltaic sources production profiles to the electricity consumption profiles in the analyzed case studies was checked. The analysis was carried out for each hour of the day and for the profiles weighted by the electricity price from the Polish Power Exchange on the Day-Ahead Market, because matching profiles at different hours has a different monetary value and, as a result, a different impact on operation costs. The highest correlation coefficient between electricity consumption and insolation on an annual basis was −0.29 in the Spearman rho-statistic for the case of M1 enterprise. On the other hand, the highest value at the level of 0.48 was achieved by the Pearson r-correlation coefficient determined on a monthly basis between the monetary value of electricity consumed and insolation in June for the M2 enterprise. Full article

(This article belongs to the Special Issue The KOMTECH-IMTech 2021 Mining Technologies Future)

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11 pages, 1885 KiB

Open AccessArticle

Study of Energy Consumption of a Bucket Conveyor in a Jig Concentrator Plant in a Hard Coal Mine

by Sebastian Jendrysik, Sławomir Bartoszek, Dominik Bałaga, Gabriel Kost and Agnieszka Sękala

Energies 2021, 14(18), 5706; https://doi.org/10.3390/en14185706 - 10 Sep 2021

Cited by 2 | Viewed by 1891

Abstract

The subject of the discussion is oriented toward limiting the energy consumption of the bucket conveyor used in jig concentrator plants by controlling its speed. A method of predictive control of the bucket conveyor speed is presented. It allows for reducing the energy [...] Read more.

The subject of the discussion is oriented toward limiting the energy consumption of the bucket conveyor used in jig concentrator plants by controlling its speed. A method of predictive control of the bucket conveyor speed is presented. It allows for reducing the energy consumption due to appropriate selection of bucket movement speed to ensure the nominal filling of buckets along the entire length of the conveyor. This approach enables limiting the idling speed of the conveyor, extend its life, and also reduce the electricity consumption of the entire system. Experimental studies, carried out at the “Sośnica” Coal Mine working facility, confirmed that the use of a predictive algorithm for controlling the bucket conveyor speed and adapting the bucket speed to the current load decreased in energy consumption n by 9.6%, with 80% of the filling conveyor. Full article

(This article belongs to the Special Issue The KOMTECH-IMTech 2021 Mining Technologies Future)

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17 pages, 7590 KiB

Open AccessArticle

Analysis and Forecasting of PM2.5, PM4, and PM10 Dust Concentrations, Based on In Situ Tests in Hard Coal Mines

by Dominik Bałaga, Marek Kalita, Piotr Dobrzaniecki, Sebastian Jendrysik, Krzysztof Kaczmarczyk, Krzysztof Kotwica and Iwona Jonczy

Energies 2021, 14(17), 5527; https://doi.org/10.3390/en14175527 - 4 Sep 2021

Cited by 6 | Viewed by 1934

Abstract

The method of analyzing the results of dust concentration measurements in mine workings that was conducted within the ROCD (Reducing risks from Occupational exposure to Coal Dust) European project using the developed dust prediction algorithm is presented. The analysis was based on the [...] Read more.

The method of analyzing the results of dust concentration measurements in mine workings that was conducted within the ROCD (Reducing risks from Occupational exposure to Coal Dust) European project using the developed dust prediction algorithm is presented. The analysis was based on the measurements of average dust concentration with the use of the CIP-10R gravimetric dust meters, for the respirable PM4 dust concentration, and IPSQ analyzer for instantaneous concentration measurements (including PM2.5 dust) and with the use of Pł-2 optical dust meters for instantaneous concentration measurements of PM10 dust. Based on the analyses of the measurement results, the characteristics of the distribution of PM10, PM4, and PM2.5 dust particles were developed for the tested dust sources. Then, functional models based on power functions were developed. The determined models (functions) allow predicting the dust distribution in such conditions (and places) for which we do not have empirical data. The developed models were implemented in a specially developed online tool, which enables predicting the concentration of PM10, PM4, and PM2.5 dust (on the basis of dust concentration of one source) at any distance from the dust source. Full article

(This article belongs to the Special Issue The KOMTECH-IMTech 2021 Mining Technologies Future)

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