Analysis of the Influence of Dynamic Load on the Work Parameters of a Powered Roof Support’s Hydraulic Leg

Szurgacz, Dawid; Brodny, Jarosław

doi:10.3390/su11092570

Cited by 52 publications

(39 citation statements)

References 13 publications

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“…The dynamic tests of the hydraulic leg of the powered roof support along with the safety system were carried out at a drop weight tester [8,23,40]. The leg was impacted with a free-falling impact mass [40,[44][45][46][47]. The leg was initially expanded in the frame of the tester by loading it with the mass of the traverse.…”

Section: Dynamic Test Of the Protection Of The Hydraulic Legmentioning

confidence: 99%

“…The crossbar weighted 3300 kg. The results of similar tests are presented in [47], where the safety valve was attached with a Stecko connector DN 12, and the crossbar weighted 1800 kg. Both tests were Energies 2020, 13, 405 10 of 22 carried out at different positions but with similar mass impact energy.…”

Section: Dynamic Test Of the Protection Of The Hydraulic Legmentioning

confidence: 99%

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Adapting the Powered Roof Support to Diverse Mining and Geological Conditions

Szurgacz

Brodny

2020

Energies

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A powered roof support is one of the most important machines of a longwall system. Its basic task is to ensure the safety and continuity of the mining process. The conditions of coal mining process are constantly changing and have significantly deteriorated in recent years, which in turn has also resulted in a significant increase in the requirements for mining support. As a result, it is necessary to develop an appropriate methodology that will facilitate the design and testing process of a power roof support as well as will help to select a roof support adjusted to given conditions. The article presents such a methodology. It is based on forecasted load impacting on a roof support, tests covering selected systems and elements of the section as well as legal conditions regarding the admission of the roof support to operation. This idea was developed in the form of a procedure that, by combining the three areas, should support the decision-making process in the case of different underground conditions. In terms of the expected load impacting on the support, the research team identified the most dangerous phenomena occurring in the rock mass that can generate these loads. Stand tests included impact load and permanent clamping of an excavation. The element that significantly impacts the safety of the support operation is a hydraulic leg, and therefore it was tested together with the safety system and the control system. Model tests were also carried out for the system with a safety valve. The developed concept takes into account legal conditions, which should include test results and different support operating conditions in a more flexible way. The main purpose of the work was to develop a comprehensive methodology for testing and assessing the possibility of using a powered roof support for given mining and geological conditions based on an analysis of safety and control systems. The presented approach is undoubtedly new and original, and can be widely used. It enables better adaptation of the support to given conditions. It also fits the research and activities designed to minimize the presence of miners or service workers in hazardous underground exploitation zones and to improve efficiency and boost sustainable development of the mining industry.

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Section: Dynamic Test Of the Protection Of The Hydraulic Legmentioning

confidence: 99%

Section: Dynamic Test Of the Protection Of The Hydraulic Legmentioning

confidence: 99%

Adapting the Powered Roof Support to Diverse Mining and Geological Conditions

Szurgacz

Brodny

2020

Energies

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“…There were numerous studies concerning the determination of the fractures zone, the results of which were presented in the papers [27,28,[54][55][56][57]. The interest in determining this zone mainly arises from the fact that its size is very important while choosing the support protecting a given heading against the deformative action of the rock mass [4,5]. However, the impact of this zone has so far not been accounted for in ventilation issues.…”

Section: Demarcation Of the Fractures Zone Around The Excavated Dog Hmentioning

confidence: 99%

“…Depending on the geological conditions of the particular headings, they are mined either in the waste rock or in coal. In recent years, in Polish hard coal mines, those headings are primarily mined in coal beds with high methane-bearing capacity [1][2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%

The Influence of the Permeability of the Fractures Zone Around the Heading on the Concentration and Distribution of Methane

Tutak¹

2019

Sustainability

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One of the main problems related to the excavation of dog headings in coal beds is the emission of methane during this process. To prevent the occurrence of dangerous concentration levels of this gas, it is necessary to use an appropriate ventilation system. The operation effectiveness of such a system depends on a number of mining, geological, technical and organizational factors. One of them includes the size and permeability of the fractures zone formed around the excavated dog heading. The primary objective of the paper is to determine the influence of this zone on the ventilation parameters, including the concentration and distribution of methane in the excavated dog heading. In order to achieve the assumed objective, multivariate model-based tests were carried out, which reproduce a real-world dog heading. Literature data and test results in actual conditions were used to determine the size and permeability of the fractures zone around the excavated heading. These data served as the basis to develop a model of the region under analysis and adopt boundary conditions. The analyses were carried out for four permeability values of the fractures zone and for two volumetric flow rates of the air stream supplied to the heading. The results were used to determine the influence of the fractures zone on the distribution and concentration of methane in the heading under analysis. The model-based tests were performed using ANSYS Fluent software. The idea to take into account the fractures zone around the heading represents a new approach to the analysis of ventilation parameters in underground mine headings. The results clearly indicate that this zone affects the ventilation parameters in the heading, including the distribution and concentration of methane. The knowledge obtained from the tests should be used to optimize the ventilation process of dog headings. All authors have read and agreed to the published version of the manuscript.Sustainability 2020, 12, 16 2 of 24 very expensive, equipment makes it necessary to provide adequate ventilation to such headings. The ventilation system must ensure proper temperature and chemical composition of air, so that the employees could freely and safely perform their work [6][7][8][9][10][11][12][13][14][15].Sustainability 2020, 12, x FOR PEER REVIEW 2 of 24 employees could freely and safely perform their work [6][7][8][9][10][11][12][13][14][15].to prevent the occurrence of dangerous methane concentration levels in those headings [7][8][9][10][11][12][13][14][15]. 50 Unfortunately, the coal beds currently excavated in Poland contain high methane deposits. As a 51 result, the dog headings mined in those coal beds are susceptible to high methane emissions. To 52 guarantee working safety for the crew and proper effectiveness of the excavation process, dangerous 53 methane concentration levels are not acceptable in such headings. This is because they may lead to 54 the combustion and/or explosion of this gas. Both of these phenomena are amongst the most 55 dangerous in the mining ...

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“…The proposed section geometry test method strengthened the support effect of the working face and ensured the safe mining problem of the working face under the influence of the dynamic load of the overburden [23]. Szurgacz carried out the test of the hydraulic support under the impact of dynamic load; the results broadened the research field of the hydraulic support in the pillar under the action of dynamic load and improved the effect of the support stability of the working face under the roof movement [24].…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on the Effect of Advancing Speed and Stoping Time on the Energy Release of Overburden in an Upward Mining Coal Working Face with a Hard Roof

et al. 2019

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In order to study the influence of advancing speed and stoping time of a coal face on the scale and frequency of rock burst, the energy release characteristics of an overburden fracture under six advancing speeds and four stoping times are studied by theoretical analysis and similar simulation experiments. The distribution characteristics of microseismic events before and after stoppage are compared, and the load/unload response ratio is introduced to analyze the relationship between the synergistic effect of advancing speed and stoping time and the characteristics of microseismic events in coal and rock mass. The mechanism of rock burst induced by the advancing speed and stoping time effect in the working face is studied, and the coordinated regulation and mitigation of advancing speed and stoping time are analyzed and completed. The results show that the effect of advancement speed and stoping time is very important to the energy release of overburden. The energy released by microseismic events during stoping is exponentially related to the advancing speed. The change of advancing speed causes the change of microseismic event characteristics, reflecting the evolution process of overburden structure and its energy. During stoping, the secondary microseismic events disturbed by mining occur frequently, leading to the significant difference of energy released by microseismic events during stoping. After stoping, the microseismic energy is more than four times higher than that during the stop period, and the risk of coal seam impact is high during the stope period. The synergetic change of advancement speed and stoping time changes the cycle of energy accumulation and release. The response ratio of loading and unloading considering the effect of advancement speed and stoping time is established by using the corresponding ratio of loading and unloading, and the impact risk of the coal seam is quantitatively analyzed. Based on the monitoring and analysis of microseismic events, the safety mining index of coordinated control with the energy of a single microseismic event of 180 J is established, and the best advancing speed of the working face is determined to be 4 m/d. According to the corresponding ratio of loading and unloading, the reasonable stoping time of different advancing speeds and the corresponding advancing speed of different stoping times after the resumption of mining are determined, so as to provide a reference for the safe and efficient mining of similar rock burst mines.

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Analysis of the Influence of Dynamic Load on the Work Parameters of a Powered Roof Support’s Hydraulic Leg

Cited by 52 publications

References 13 publications

Adapting the Powered Roof Support to Diverse Mining and Geological Conditions

Adapting the Powered Roof Support to Diverse Mining and Geological Conditions

The Influence of the Permeability of the Fractures Zone Around the Heading on the Concentration and Distribution of Methane

Experimental Study on the Effect of Advancing Speed and Stoping Time on the Energy Release of Overburden in an Upward Mining Coal Working Face with a Hard Roof

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