Energies

Research

18 pages, 7780 KiB

Open AccessArticle

Geomechanical and Technical Aspects of Torpedo Blasting under Seismic and Rockburst Hazard Conditions in Legnica–Glogow Copper District Mines

by Zbigniew Burtan, Jerzy Cieślik, Dariusz Chlebowski, Paweł Piasecki and Krzysztof Gzik

Energies 2024, 17(5), 1174; https://doi.org/10.3390/en17051174 - 1 Mar 2024

Viewed by 483

Abstract

The dominant hazard in the Polish copper ore mining industry (LGCD mines—Legnica–Glogow Copper District) is the occurrence of mining tremors and rockbursts. One of the effective active methods of preventing this threat is torpedo blasting, which results in disturbing the structure of roof [...] Read more.

The dominant hazard in the Polish copper ore mining industry (LGCD mines—Legnica–Glogow Copper District) is the occurrence of mining tremors and rockbursts. One of the effective active methods of preventing this threat is torpedo blasting, which results in disturbing the structure of roof rocks. A change in the integrity of a roof, especially in the tremor-generating layer or in the contact between stiff rock layers, reduces the possibility of an elastic energy concentration and may also be a kind of stress concentrator, provoking the destruction of rocks. This article presents original solutions for determining the areas of rock mass within a mining area where it is advisable to conduct torpedo blasting, and the experience of blasting in the Rudna copper mine in the LGCD is described. The first part of this article presents the results and experiences of using torpedo blasting prevention in the LGCD mine conditions in the Rudna mine. Assuming that due to the stress of the rocks, torpedo blasting brings the greatest benefits in the areas of elastic energy concentration, the second part of this article presents the results of numerical modeling, on the basis of which the zones of elastic energy concentration in the form of total, shear and volume deformation were determined in the vicinity of mining activities for typical geological and mining conditions in the LGCD. The importance of methods for the verification of the proposed solutions based on the analysis of seismic activity and geophysical mechanisms of events’ foci and seismo-acoustic emissions was also emphasized. The numerical simulations performed and conclusions from in situ observations allowed the formulation of general principles for the selection of torpedo blasting parameters. Full article

(This article belongs to the Special Issue Mining Innovation: Volume III)

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17 pages, 12857 KiB

Open AccessArticle

Application of an Analytical Model of a Belt Feeder for Assessing the Load and Stability of Its Structure

by Krzysztof Krauze, Tomasz Wydro, Ryszard Klempka and Kamil Mucha

Energies 2023, 16(24), 8111; https://doi.org/10.3390/en16248111 - 17 Dec 2023

Viewed by 737

Abstract

Belt conveyors, owing to their simple construction, high reliability and relatively low energy consumption, are the basic means of transporting loose and granular materials. Currently, thanks to continuous development, belt conveyors can reach a length of up to several kilometres, and their belt [...] Read more.

Belt conveyors, owing to their simple construction, high reliability and relatively low energy consumption, are the basic means of transporting loose and granular materials. Currently, thanks to continuous development, belt conveyors can reach a length of up to several kilometres, and their belt width can be more than two meters. Such possibilities are achieved thanks to increasingly better belts and drives. However, the most common are short belt conveyors with a length of up to 40 m and belt widths of up to 1 m, frequently referred to as belt feeders. Apart from the mining industry, they are widely used in power engineering, metallurgy and other industries (chemical plants, trans-shipment ports, storage yards, etc.). The design of machines, including belt feeders, is based on calculations. Modern design in technology is based on advanced computational methods and the possibilities of computer technology. Multi-variant simulation calculations are necessary, especially in the case of belt feeders, where none of the devices—despite the use of typical elements and subassemblies—are a repeatable solution. Only this procedure guarantees the selection of rational solutions already at the early stages of design. Therefore, in this article, an analytical model of a typical belt feeder was developed and its stability and forces in the supports were determined. This allowed the development of an application for testing the stability of the belt feeder at the design stage or when introducing structural changes. Full article

(This article belongs to the Special Issue Mining Innovation: Volume III)

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27 pages, 13739 KiB

Open AccessArticle

Study on the Usefulness of Lean Management Tools and Techniques in Coal Mines in Poland

by Marek Kęsek, Paweł Bogacz and Marcin Migza

Energies 2023, 16(21), 7240; https://doi.org/10.3390/en16217240 - 25 Oct 2023

Cited by 1 | Viewed by 1269

Abstract

The article presents research on the possibilities of utilising the Lean Management method to increase the profitability of coal mining operations through cost rationalisation and production optimisation. The Lean Management method has its roots in the automotive industry, but its significant benefits can [...] Read more.

The article presents research on the possibilities of utilising the Lean Management method to increase the profitability of coal mining operations through cost rationalisation and production optimisation. The Lean Management method has its roots in the automotive industry, but its significant benefits can allow it to be transferred to other industries. Based on the analysis of global literature describing examples of its application in general mining, as well as the authors’ own observations related to Polish hard coal mining, it was determined that the Lean Management method is not being utilised in this field. This article outlines the course and results of an original expert-mathematical study to assess the usefulness of specific Lean Management tools and techniques in hard coal mining. The study drew on knowledge obtained from selected, competent experts who demonstrated high levels of agreement in their assessments. Five core production areas were identified, and twelve widely used Lean Management tools and techniques were selected. The obtained assessments of the usefulness of Lean tools could serve as valuable guidance for mining management in the selection of methods for improving mining production in coal mines. Full article

(This article belongs to the Special Issue Mining Innovation: Volume III)

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21 pages, 11887 KiB

Open AccessArticle

The Impact of Vibrating Screen Startup Time on Vibration Amplitude and Energy Consumption in Transient State

by Jacek Feliks and Paweł Tomach

Energies 2023, 16(20), 7129; https://doi.org/10.3390/en16207129 - 18 Oct 2023

Cited by 1 | Viewed by 955

Abstract

The article presents the results of research on the trajectory and amplitude values during the startup of a vibrating screen, depending on the set startup time. The research was conducted using a suspended vibrating screen with a segmental vibration trajectory, where vibration excitation [...] Read more.

The article presents the results of research on the trajectory and amplitude values during the startup of a vibrating screen, depending on the set startup time. The research was conducted using a suspended vibrating screen with a segmental vibration trajectory, where vibration excitation was achieved through two vibratory motors directly attached to the screen frame. The vibratory motors were powered with three-phase voltage and connected to the grid through frequency converters, allowing for current control in steady-state and startup conditions. The analysis focused on the vibration trajectory and the resulting amplitude values for nine selected startup times (ranging from 0 s to 8 s). Two measurement methods were employed: using piezoelectric acceleration sensors and optical recording. Additionally, the momentary power consumption by the screen drive was recorded, and the maximum current flowing in the power supply circuit was determined. These studies enabled the determination of the most favourable startup parameters that reduce the power demand of the drive without significantly affecting the kinematic parameters of the screen during its startup. The results of experimental research presented in the article regarding the startup time of the screening machine and its influence on vibration parameters have shown that the startup time significantly impacts the amplitude values that occur during startup. In the analysed case, the most favourable startup time was 3 s. Power consumption studies during startup revealed that startup time has a notable influence on momentary power consumption. The conducted research demonstrated that for startup times below 0.2 s, the maximum momentary power was the highest (reaching 5 kW, with a current consumption of 4.5 times the rated current). Regarding energy efficiency, the most favourable startup times exceed 2.0 s. Extending these startup times can significantly reduce the power demand of the drive, even up to threefold, thereby enabling the selection of motors with much lower power ratings. Full article

(This article belongs to the Special Issue Mining Innovation: Volume III)

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20 pages, 14281 KiB

Open AccessArticle

Numerical Investigation of the Influence of Roof-Cutting Parameters on the Stability of Top Coal Gob-Side Entry Retaining by Roof Pre-Fracturing in Ultra-Thick Coal Seam

by Yongkang Yang, Peipeng Gao, Chao Zhang and Chenlong Wang

Energies 2023, 16(12), 4788; https://doi.org/10.3390/en16124788 - 18 Jun 2023

Cited by 2 | Viewed by 871

Abstract

Gob-side entry retaining by roof cutting, a pillarless mining technique, plays a critical role in maintaining continuous production, rapid connection, and enhancing the coal recovery rate in fully mechanized top coal caving working faces. This technique stands as a sustainable development method in [...] Read more.

Gob-side entry retaining by roof cutting, a pillarless mining technique, plays a critical role in maintaining continuous production, rapid connection, and enhancing the coal recovery rate in fully mechanized top coal caving working faces. This technique stands as a sustainable development method in coal mining. The present research, set against the backdrop of the Yitang Coal Mine 100602 top coal gob-side entry retaining by roof cutting, investigates the influence of roof-cutting borehole depth, borehole dip angle, mining height, and coal seam thickness on stability in an ultra-thick coal seam under 12 distinct mining conditions. A typical model of overburden structure post-roof pre-splitting was established to study the failure mechanism of the top coal roof. The results reveal that the dip angle and depth of the roof pre-fracturing borehole significantly impact the movement characteristics of the overlying strata. Optimal conditions are found when the dip angle and depth of the roof pre-fracturing borehole, the mining height, and the top coal thickness are 10°, 16 m, 4 m, and 4 m, respectively. Under these circumstances, the load transfer from the goaf to the gob-side entry can be effectively intercepted, mitigating the influence of roof fracture activities on the top coal gob-side entry. Field measurements confirm that suitable anchor-net support can stabilize the roof’s rock structure. This research underpins the significance of roof pre-fracturing for the promotion and application of top coal gob-side entry retaining by roof cutting in ultra-thick coal seams. Full article

(This article belongs to the Special Issue Mining Innovation: Volume III)

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17 pages, 3818 KiB

Open AccessArticle

Electro-Mechanical Modeling and Evaluation of Electric Load Haul Dump Based on Field Measurements

by Gabriel Freire, Guillermo Ramirez, René Gómez, Krzysztof Skrzypkowski and Krzysztof Zagórski

Energies 2023, 16(11), 4399; https://doi.org/10.3390/en16114399 - 30 May 2023

Viewed by 1195

Abstract

In underground mining, conventional loader equipment uses diesel as a power source, implying different drawbacks, such as combustion gases, low visibility, worker’s health problems, and high ventilation requirements. Thus, hybrid and electric loaders are being developed by the main industry suppliers who prefer [...] Read more.

In underground mining, conventional loader equipment uses diesel as a power source, implying different drawbacks, such as combustion gases, low visibility, worker’s health problems, and high ventilation requirements. Thus, hybrid and electric loaders are being developed by the main industry suppliers who prefer clean technology. In this study, we analyzed the performance of an electro-mechanical powertrain through a dynamic model of underground-loader equipment using field data. This electric LHD model was compared to a diesel loader under the same operational conditions. For the case study, the results showed that the proposed electro-mechanical model, considering 14 tons of capacity, consumed 86.8 kWh, representing 60.5% less energy than the diesel loader with similar speed and torque characteristics. Thus, the proposed methodology is a valuable tool for operators, process engineers, and decision-makers, allowing an energy-efficiency evaluation for electric LHD adoption, based on the current operational data available for conventional equipment. Full article

(This article belongs to the Special Issue Mining Innovation: Volume III)

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14 pages, 5026 KiB

Open AccessArticle

Sorption–Dilatometric Properties of Coal from a High-Methane Mine in a CO₂ and CH₄ Atmosphere

by Paweł Baran, Stanisław Kozioł, Katarzyna Czerw, Adam Smoliński and Katarzyna Zarębska

Energies 2023, 16(4), 1785; https://doi.org/10.3390/en16041785 - 10 Feb 2023

Cited by 1 | Viewed by 1039

Abstract

Although highly developed countries are trying to diversify away from coal-based energy, many economies rely on this resource. Its consumption results in the production of carbon dioxide, which promotes global warming, necessitating its sequestration. This paper presents the sorption–dilatometric relationships of hard coal [...] Read more.

Although highly developed countries are trying to diversify away from coal-based energy, many economies rely on this resource. Its consumption results in the production of carbon dioxide, which promotes global warming, necessitating its sequestration. This paper presents the sorption–dilatometric relationships of hard coal samples differing in vitrinite and inertinite content. The studies were carried out under isothermal conditions (298 K) at a free pressure drop complemented by measurements under non-isothermal conditions (298 K to 323 K). The tests were performed on an original apparatus, based on the operation of an Arduino microcontroller. For the natural porosity to be preserved and for a better representation of the behaviour of the coal–gas system, samples in the form of cuboidal blocks were used, making this apparatus unique worldwide. Based on the study, it appears that the difference in petrographic composition affects the behaviour of the coal structure, influencing differences in the sorption–dilatometric properties. In the case of the sample with higher vitrinite content, the amount of adsorbed gases is higher. Full article

(This article belongs to the Special Issue Mining Innovation: Volume III)

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19 pages, 12924 KiB

Open AccessArticle

Development of Longwall Shearers’ Haulage Systems as an Alternative to the Eicotrack System Used Nowadays

by Krzysztof Kotwica, Grzegorz Stopka, Andrzej N. Wieczorek, Marek Kalita, Dominik Bałaga and Michał Siegmund

Energies 2023, 16(3), 1402; https://doi.org/10.3390/en16031402 - 31 Jan 2023

Cited by 2 | Viewed by 1447

Abstract

Longwall shearers’ haulage system of the Eicotrack type, used most often nowadays, is presented in this article. Its disadvantages, causing problems with a correct operation of mechanized longwall shearer systems, are discussed. The concept of the innovative Flextrack, which should reduce the occurrence [...] Read more.

Longwall shearers’ haulage system of the Eicotrack type, used most often nowadays, is presented in this article. Its disadvantages, causing problems with a correct operation of mechanized longwall shearer systems, are discussed. The concept of the innovative Flextrack, which should reduce the occurrence of the disadvantages mentioned above, is described. A course and research results, connected with rig tests of the Flextrack haulage system functionality, are presented. Measurement results of wear and stresses, obtained for the Eicotrack and Flextrack haulage systems, are compared and presented. Based on an analysis of the obtained results, a modified version of the Komtrack haulage system was suggested and manufactured. This haulage system was tested in the field conditions, similar to underground conditions in a mine coal longwall. The obtained results confirmed its full functionality and lack of problems experienced in the case of the Eicotrack and Flextrack systems. At present, the Komtrack system is tested in a coal longwall in Piast coal mine, where comparative tests with the Eicotrack system are conducted. The big part of the results presented in this article was developed as part of the research project KOMTRACK jointly implemented by KOMAG Institute of Mining Technology, AGH University of Science and Technology, Łukasiewicz Research Network—Cracow Institute of Technology, Specodlew Innovative Foundry Company and Polish Mining Group Inc., co-financed by the European Regional Development Fund (Contract No. POIR.04.01.04-00-0068/17). Full article

(This article belongs to the Special Issue Mining Innovation: Volume III)

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14 pages, 3464 KiB

Open AccessArticle

Determination of the Salt-Dust Emission and the Efficiency of the Dedusting Installation in the Wieliczka Salt Mine

by Mariusz Kapusta and Krzysztof Skrzypkowski

Energies 2022, 15(21), 8122; https://doi.org/10.3390/en15218122 - 31 Oct 2022

Viewed by 1112

Abstract

This article presents measurements of the emission of salt dust discharged into the atmosphere in the Wieliczka Salt Mine. Industrial tests have been carried out cyclically since 2004. The research methodology included six measurements of the salt dust’s mass increments on the filters, [...] Read more.

This article presents measurements of the emission of salt dust discharged into the atmosphere in the Wieliczka Salt Mine. Industrial tests have been carried out cyclically since 2004. The research methodology included six measurements of the salt dust’s mass increments on the filters, including three before the inlet to the desalination installation and three measurements at the emitter outlet. In order to limit errors resulting from the diversity of concentrations in the mixture of dosed brine, three series of measurements are carried out each time. The proposed research methodology uses the Aspirator Stationary (AS-50) gravimetric aspirator for measurements with a designed probe adjusted to the characteristics of the dedusting installation used. The conducted tests allowed calculation of the efficiency of the scrubber and confirm the usefulness of the measuring probe used. Moreover, long-term and cyclical measurements make it possible to observe the effectiveness of the installation and salt production using the wet system from brine obtained in the mine. The proposed method is an innovative solution for monitoring salt-dust emissions in mining applications. Full article

(This article belongs to the Special Issue Mining Innovation: Volume III)

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Review

Jump to: Research, Other

24 pages, 6216 KiB

Open AccessReview

Review of Underground Mining Methods in World-Class Base Metal Deposits: Experiences from Poland and Chile

by Krzysztof Skrzypkowski, René Gómez, Krzysztof Zagórski, Anna Zagórska and Roberto Gómez-Espina

Energies 2023, 16(1), 148; https://doi.org/10.3390/en16010148 - 23 Dec 2022

Cited by 5 | Viewed by 3039

Abstract

There are several massive deposits around the world with different geological characteristics. Thus, different mining methods and strategies are applied based on the particularity of each method and mine experience. Particularly, in this work, we review and summarize the underground exploitation of some [...] Read more.

There are several massive deposits around the world with different geological characteristics. Thus, different mining methods and strategies are applied based on the particularity of each method and mine experience. Particularly, in this work, we review and summarize the underground exploitation of some world-class base metal deposits based on Poland and Chilean experiences. Here, the main geological and mining parameters of Poland and Chilean mines applied in massive deposits are reported and analyzed. In Poland, mainly room and pillar methods (and variants) have been applied in massive deposits. Here, back-filling is required to maintain the mine’s stability due to the large deposit size and open areas. In Chile, the block caving method is commonly used in massive underground deposits where less development is required. Here, the cave is naturally filled with broken material and a large subsidence zone is generated. In this review, it has been observed that different underground methods and strategies can be effectively used in massive deposits. Some parameters that influenced the method selection are mainly related to rock mechanics, ore recovery and dilution, subsidence zone, extraction rate, and mining experience. Here, key mining variables and parameters such as productivity, support, and equipment, as well as various issues related to the world-class deposit are studied. Additionally, a comparison between both experiences is presented, highlighting the main geological and mining parameters. This study can be used as a reference to evaluate the different option of underground mining methods to be applied in future massive mine projects with similar geological characteristics. Full article

(This article belongs to the Special Issue Mining Innovation: Volume III)

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Other

Jump to: Research, Review

16 pages, 2640 KiB

Open AccessPerspective

Access to Deposits as a Stage of Mining Works

by Krzysztof Skrzypkowski, Krzysztof Zagórski, Anna Zagórska and Fhatuwani Sengani

Energies 2022, 15(22), 8740; https://doi.org/10.3390/en15228740 - 21 Nov 2022

Cited by 4 | Viewed by 4467

Abstract

An extremely important role in the underground method of mining deposits is the type of access, which is the initial stage of the mining operations. The main feature of mineral deposits is their exhaustiveness and the inability to restore resources. This necessitates the [...] Read more.

An extremely important role in the underground method of mining deposits is the type of access, which is the initial stage of the mining operations. The main feature of mineral deposits is their exhaustiveness and the inability to restore resources. This necessitates the rational management of deposit resources, especially the minimization of resource losses during exploitation. This article presents information on the mining area and methods of access the deposits. In particular, attention was paid to the advantages and disadvantages of access by means of an adit, decline, and a vertical and inclined shaft. Given the relationships among the various stages of mining works, it was found that the number of active levels depends on the volume of production and the adopted mining methods. In addition, attention was drawn to the fact that the access to deposits at increasing depth is related to the intensification of natural hazards that affect the access structure. Full article

(This article belongs to the Special Issue Mining Innovation: Volume III)

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