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Number of results: 135
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Abstract

Steel arch-rectangular support has a wide range of applications in Polish coal mines due to its asymmetrical shape. The frame has an arched outline on one side of the side wall, while on the opposite side it is rectangular. As a result, the support is ideal for securing set up room and recovery room. It can also be successfully used to secure three-way intersections of underground workings. To a large extent, however, the importance of these advantages is diminished by relatively low load-bearing parameters, resulting from a partially straight canopy, as well as the asymmetrical distribution of the load acting on the support in underground conditions. In order to ensure the proper and optimal operation of such frames, in addition to the standard requirements for roof supports, additional conditions must be met. The basic requirement is to support the end of the canopy on the corner of the excavation. This article presents examples of arch-rectangular supports, their applications as well as laboratory tests and strength analysis of the frames and its elements. These tests allowed the requirements regarding the construction of the frame, the selection of the support and the conditions of building in the excavation to be specified.

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Authors and Affiliations

Marek Rotkegel
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Abstract

Steel yielding arch support constructed of V profiles is commonly used to protect galleries and, in some cases, to reinforce or secure a shaft support. For this purpose, a closed, circular-shaped arch support is used, with arches overlapped by clamps that are typical for this type of construction. The support has high resistance to the impact of even (distributed over the entire surface of the support) load, however, as a result of significant deformation associated with a change in the radius of the curvatures, the support shows limited yielding capacity. This is due to the increase in resistance to slide on the locks, resulting from changes in the geometry of the ring caused by the rock mass. This article presents the results of research and analysis concerning the elements of the arch support with notches in arches. The research team tested the effect of the depth and location of the notches of the section’s flanges on the load impacting on the clamp’s bolts and the strength of the roof support. Moreover, the tests covered the influence of the number and location of clamps in a frictional joint on the change in the nature of work and yielding capacity. Finally, the research included both strength tests of the support’s elements, as well as strength analyses based on the finite element method.

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Authors and Affiliations

Marek Rotkegel
ORCID: ORCID
Łukasz Szot
Sławomir Fabich
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Abstract

The problems related to construction production are multi-faceted and complex. This has promoted the search for different methods/approaches for analizing the data which supports the decision-making process in the construction industry. In the article the authors focus their attention on well-known methods and tools, and on some new approaches to solving decision-making problems. The aim of the article is to analyze the methods used to analyse data in a construction company, convey their advantages and disadvantages, and specify the degree of efficiency in the discussed area.

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Authors and Affiliations

A. Dziadosz
A. Kończak
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Abstract

The mining of hard coal deposits at increasingly greater depth leads to an increase in hazards related to the loss of stability of steel arch supports as a result of excessive static and dynamic loads. Camber beam reinforcement via rockbolting is often utilised in order to improve the stability of the yielding steel arch support.

This article presents the results of comparative bench tests of the ŁP10/V36-type steel arch support, tested with and without reinforcement by means of self-drilling bolts with drunken R25 threads, using short joists formed from V32 and V25 sections. It also presents the results of comparative tests of the ŁPP10/4/V29/I-type steel arch support, tested with and without reinforcement by means of rock bolts with trapezoidal Tr22/13 threads, using short joists formed from V25 sections. The obtained test results, in the form of load courses and work values of the steel arch and mixed (arches and rock bolts) support systems, demonstrate that the utilisation of mixed support may significantly improve the stability of workings, particularly immediately after they are driven. A mixed support system quickly achieves its maximum load capacity together with a significant increase in its work value. It may thus prevent the stratification of the rocks surrounding the working, and therefore better utilise the self-supporting capacity of the rock mass. As evidenced by the test results, the mixed support work may be as much as 3.5 times as great compared to the steel arch support at the beginning of the height reduction process initiated by loading – i.e. until its reduction by a presupposed value of 100 mm.

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Authors and Affiliations

Andrzej Pytlik
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Abstract

The pandemic prompted young people to develop different strategies for coping with stress. Disruption of societal reality and the need to adapt to new situation affected people’s well-being significantly.The research was conducted between 15 and 30 June 2020 on a group of 151 students. The following tools were used: Ryff’s Psychological Well-Being Scales in the Polish adaptation and the authors' own tool for measuring coping with a pandemic situation and its perception. In addition to quantitative analysis, qualitative analysis was used. Well-being was found to be related to the perception of pandemic, the sense of coping with pandemic, the sense of support, and the sense of control. Within these relationships the gender differences were found. Social support turned out to be the most significant correlate of well-being in both men and women. Qualitative analyses identified three sub-models for each gender. The criterion that allowed us to select different groups of cases was subjects’ perception of the pandemic influence on their lives. The hypothesis: "Perception of the pandemic as a meaningful situation is related to psychological well-being" was confirmed only in the female group. The hypothesis: "Sense of better coping, feeling more supported, feeling more accepted, and feeling more in control are positively associated with psychological wellbeing" was confirmed (except for acceptance). Qualitative analyses showed that women were more involved in building social support network and experienced a stronger loss of control over the crisis. Men manifested greater autonomy and resourcefulness in emergency situation.
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Authors and Affiliations

Monika Dacka
1
ORCID: ORCID
Agata Wolanin
2
ORCID: ORCID
Jan Rybak
3
ORCID: ORCID

  1. The John Paul II Catholic University of Lublin, Lublin, Poland
  2. Independent Researcher, Sanok, Poland
  3. Rzeszów University of Technology, Rzeszow, Poland
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Abstract

The aim of this study is to present an exemplary cartographic visualization of fi re hydrants data consisting of a set of thematic maps containing various information related to the location of hydrants, buildings and driveways in geographic space, and relationships existing between them. Identification of these relationships requires spatial analysis, and illustrating them requires the use of appropriate cartographic presentation methods. The study was conducted on a part of the city of Poznan using data on hydrants’ location and type collected and provided by the Fire Department. Geometric data, obtained using geoprocessing algorithms, were assigned appropriate symbols, which lets differentiate them qualitatively and quantitatively. An emphasis is placed on the use of adequate visual variables and on the cartographic communication efficiency. The result of the study is a cartographic visualization in the form of series of thematic maps arranged in a logical sequence, and providing information about the secured area. The thematic layers presenting the same area were arranged in different arrangements with maintenance of the reference layers, ensuring the ease of correlation. Such a cartographic visualization provides knowledge about the spatial distribution and diversity of objects and the relationships between them. It may be an important source of knowledge both at the identification stage and at the operational stage when conducting a fire fighting action.
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Authors and Affiliations

Łukasz Wielebski
Beata Medyńska-Gulij
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Abstract

The paper presents the experience of using the ŁPrP, ŁPKO, ŁPSp, ŁPSpA i ŁPSp3R types of flattened supports for longwall entries in the conditions of the JSW S.A. Knurów-Szczygłowice coal mine. The article concentrates on the support solutions applied in the conditions of the mine and the results in terms of stability and usefulness of the structures of the supports. An analysis of the load bearing capacity and technological conditions has been conducted for various flattened supports solutions, with special consideration given to the ŁPSp and ŁPrPJ support sets. Comparing these two, the ŁPSp exhibits a load bearing capacity that is 21% higher while using 31% less steel mass. The experiment results allowed to determine that the ŁPSpA and ŁPSp3R support types are an advantageous solutions in case of longwall set-up rooms.

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Authors and Affiliations

Piotr Głuch
Grzegorz Michalik
Tomasz Śledź
Piotr Kleibert
Adam Ratajczak
Jarosław Sobik
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Abstract

Power electronic circuits (PECs) are prone to various failures, whose classification is of paramount importance. This paper presents a data-driven based fault diagnosis technique, which employs a support vector data description (SVDD) method to perform fault classification of PECs. In the presented method, fault signals (e.g. currents, voltages, etc.) are collected from accessible nodes of circuits, and then signal processing techniques (e.g. Fourier analysis, wavelet transform, etc.) are adopted to extract feature samples, which are subsequently used to perform offline machine learning. Finally, the SVDD classifier is used to implement fault classification task. However, in some cases, the conventional SVDD cannot achieve good classification performance, because this classifier may generate some so-called refusal areas (RAs), and in our design these RAs are resolved with the one-against-one support vector machine (SVM) classifier. The obtained experiment results from simulated and actual circuits demonstrate that the improved SVDD has a classification performance close to the conventional one-against-one SVM, and can be applied to fault classification of PECs in practice.
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Authors and Affiliations

Jiang Cui
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Abstract

Half a century ago two papers were published, related to generalized inverses of cracovians by two different authors, in chronological order, respectively by Jean Dommanget and by Helmut Moritz. Both independently developed papers demonstrated new theorems, however, certain similarity between them appeared. Helmut Moritz having recognized that situation, promised to mention it later in one of his published papers. This has never been done, so the author of the present paper gives some details about the situation and claims his paternity.
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Authors and Affiliations

Jean Dommanget
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Abstract

Preventive methods of plant protection used currently require a significant number of treatments throughout the season. Research results indicate a possibility of reduction of the number of treatments by halfwithout serious loss of effectiveness if the attack of pathogens has been recorded early enough. Limiting treatments to truly necessary ones means conserving chemicals, fuel and labour and consequently substantial financial savings for the farm. However, early warning requires full analysis of many factors that influence incidence, development and harmfulness of diseases, pests and weeds in relation with their impact on the yield. Such an analysis is beyond the power of the farmer alone. Appropriate models have to be used that utilize weather data and field observations in real time. At the present, due to frequent updating of the databases and sharing of the system by many users, in integrated plant protection the most efficient seem to be internet decision support systems. As of 2000 the Institute of Plant Protection in Poznań together with the Institute Soil Science and Plant Cultivation in Puławy in cooperation with the Danish Institute of Agricultural Sciences conduct a joint research project on development and implementation of an Internet Decision Support System for Integrated Plant Protection in Poland. Various modules of the system are already available on the Internet. Much like similar systems operating abroad, the Polish DSS also takes advantage of weather data utilized in disease models (the weather module). Nevertheless, an important addition to the system are strategically relevant data such as values and statistic distributions of elements of climate and potential yields (the agroclimate module), operation sheets, exploitation data and prices (the technology module) etc., which are important to the formulation and adoption of a particular line of action and risk evaluation in economic terms. When all modules are operational, the information relevant to decision making will be derived from on-line analyses based on cost calculation of different variants of plant protection applicable to the current situation.
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Authors and Affiliations

Andrzej S. Zaliwski
Stefan Wolny
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Abstract

In the paper an approach to decision making in situations with non-point-like characterisation and subjective evaluation of the actions is considered. The decision situation is represented mathematically as fuzzy multiobjective linear programming (fMOLP) model, where we apply the reduced fuzzy matrices instead of fuzzy classical numbers. The fMOLP model with reduced parameters is decomposable into the set of point-like models and the point-like models enable effective construction of an optimisation procedure – fBIP, see Wojewnik (2006ab), extending the bireference procedure by Michalowski and Szapiro (1992). The approach is applied to a fuzzy optimization problem in the area of telecommunication services.

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Authors and Affiliations

Piotr Wojewnik
Tomasz Szapiro
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Abstract

Open pit mining of rock minerals and the affected areas requiring further development are a serious challenge for shaping the positive image of the mining industry among the public. The direction and method of post-mining land reclamation are important for this image, which should take into account various factors describing the mining area, including social preferences. The article presents an example solution – fuzzy system (FSDR) – which supports the selection of the direction of reclamation of post-mining areas created after the termination of operations of open pit gravel and sand natural aggregate mines. The article presents selected factors determining the selection of the direction and possible reclamation variants as input and output data of the fuzzy system. The rules base of the developed system, as well as the mechanisms of inference and defuzzification, were also characterized. The application of the developed system is presented on selected examples.

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Authors and Affiliations

Jadwiga Król-Korczak
Edyta Brzychczy
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Abstract

The article presents the results of tests on SHC-40 hydraulic props equipped with two types of valve blocks: standard (with spring steel cylinder) and BZG-2FS (with gas spring). The research was conducted using impact mass of 4,000 kg and with extreme dynamic load of free fall impact mass of 20,000 kg released from different heights h. The dynamic tests involved a camera with the speed of image capture up to 1,200 frames/sec, which made it possible to register the stream of liquid at the dynamic load and to determine the valve opening time. The study conducted on SHC-40 NHR10 props equipped with two types of valve blocks: a standard and the BZG-2FS fast acting relief, showed that the prop with the BZG-2FS block is more suitable and more effective in the case of areas with high risk of mining tremors and rapid stress relief of a seam. Research methodology developed in the Central Mining Institute combines digital recording technique of pressure in a prop and fast registration of the images, and allows to acquire more accurate analysis of dynamic phenomena in the prop during testing.
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Authors and Affiliations

Andrzej Pytlik
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Abstract

In the field experiments performed in 1999–2001 the profitability of late blight control in accordance with three decision support systems: NegFry, Simphyt and Stephan with routine fungicide program was compared. Potato protection carried out according to the recommendations of the decision support systems guaranteed higher profitability of late blight control than when potato was protected routinely. The highest profitability was recorded for susceptible variety Bekas protected according to NegFr.

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Authors and Affiliations

Andrzej Wójtowicz
Jerzy J. Lipa
Erich Jörg
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Abstract

This paper proposes a soft sensing method of least squares support vector machine (LS-SVM) using temperature time series for gas flow measurements. A heater unit has been installed on the external wall of a pipeline to generate heat pulses. Dynamic temperature signals have been collected upstream of the heater unit. The temperature time series are the main secondary variables of soft sensing technique for estimating the flow rate. A LS-SVM model is proposed to construct a non-linear relation between the flow rate and temperature time series. To select its inputs, parameters of the measurement system are divided into three categories: blind, invalid and secondary variables. Then the kernel function parameters are optimized to improve estimation accuracy. The experiments have been conducted both in the single-pulse and multiple-pulse heating modes. The results show that estimations are acceptable.
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Authors and Affiliations

Weiqing Xu
Zichuan Fan
Maolin Cai
Yan Shi
Xiaomeng Tong
Junpeng Sun
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Abstract

This paper presents the design process and the results of a novel fall detector designed and constructed at the Faculty of Electronics, Military University of Technology. High sensitivity and low false alarm rates were achieved by using four independent sensors of varying physical quantities and sophisticated methods of signal processing and data mining. The manuscript discusses the study background, hardware development, alternative algorithms used for the sensor data processing and fusion for identification of the most efficient solution and the final results from testing the Android application on smartphone. The test was performed in four 6-h sessions (two sessions with female participants at the age of 28 years, one session with male participants aged 28 years and one involving a man at the age of 49 years) and showed correct detection of all 40 simulated falls with only three false alarms. Our results confirmed the sensitivity of the proposed algorithm to be 100% with a nominal false alarm rate (one false alarm per 8 h).
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Authors and Affiliations

Bartłomiej Wójtowicz
Andrzej Dobrowolski
Kazimierz Tomczykiewicz
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Abstract

As experience shows the practical, reliable assessment and optimisation of total costs of logistical processes implemented in supply chains

of foundry plants is a quite complex and complicated process, because it requires to enclose all, without exception, performed actions,

including them in various reference cross-sections, systematic activities and finally transforming them in a totally homogenous collection.

Only solid analysis and assessment of assortment management in logistical supply systems in foundry plants of particular assortment

groups allows to lower the supply costs significantly. In the article the analysis and assessment of the newest implemented optimising

algorithms are presented in the process stock management of selected material groups used in a production process of a chosen foundry

plant. A practical solution to solve a problem of rotary stock cost minimisation is given as well as of costs while creating a stock with the

usage of economical volume and value of order.

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Authors and Affiliations

J. Szymszal
M. Kuczyńska-Chałada
J. Król
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Abstract

A significant part of the knowledge used in the production processes is represented with natural language. Yet, the use of that knowledge

in computer-assisted decision-making requires the application of appropriate formal and development tools. An interesting possibility is

created by the use of an ontology that is understandable both for humans and for the computer. This paper presents a proposal for

structuring the information about the foundry processes, based on the definition of ontology adapted to the physical structure of the

ongoing technological operations that make up the process of producing castings.

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Authors and Affiliations

Z. Górny
D. Wilk-Kołodziejczyk
A. Smolarek-Grzyb
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Abstract

Affective computing studies and develops systems capable of detecting humans affects. The search for universal well-performing features for speech-based emotion recognition is ongoing. In this paper, a small set of features with support vector machines as the classifier is evaluated on Surrey Audio-Visual Expressed Emotion database, Berlin Database of Emotional Speech, Polish Emotional Speech database and Serbian emotional speech database. It is shown that a set of 87 features can offer results on-par with state-of-the-art, yielding 80.21, 88.6, 75.42 and 93.41% average emotion recognition rate, respectively. In addition, an experiment is conducted to explore the significance of gender in emotion recognition using random forests. Two models, trained on the first and second database, respectively, and four speakers were used to determine the effects. It is seen that the feature set used in this work performs well for both male and female speakers, yielding approximately 27% average emotion recognition in both models. In addition, the emotions for female speakers were recognized 18% of the time in the first model and 29% in the second. A similar effect is seen with male speakers: the first model yields 36%, the second 28% a verage emotion recognition rate. This illustrates the relationship between the constitution of training data and emotion recognition accuracy.

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Authors and Affiliations

J. Hook
F. Noroozi
O. Toygar
G. Anbarjafari
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Abstract

This paper presents a new method of calculation of the change of axial twisting angle of compressed helical spring’s end-coils in the case of rotary - free supports. The propriety of derived formulas was experimentally verified. The method is easy in application and gives results much closer to experiment than the presently used method that can be found in literature.

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Authors and Affiliations

Krzysztof Michalczyk
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Abstract

Having increasingly tightened geological and mining conditions in which the extraction of copper ore deposits in Poland is conducted, ensuring effective and safe mining is presently becoming a key task and a significant challenge for mine operators, mainly in the field of ground support systems being the equivalent for the new geological/mining conditions. As one may expect, these conditions shall be characterized by higher values of the primary stress tensor elements as well as the lower deformability and higher strength of the rock mass surrounding the copper ore body. T his means that in the near future, the rock bursts problem will become one of the most important issues deciding on the economy and safety within the newly developed mining areas. T herefore developing a novel effective ductile ground support systems which could be able to control the rock mass movement in squeezing and burst-prone rock conditions is recommended. T his type of requirement may fulfil only ductile or, in other words, the kinetic energy-absorbing systems, which permit slowing down a movement of violently ejected rock blocks. T his paper’s objective is to present the idea of the development of a new type of an effective and low cost ductile resin anchored rockbolt system with smooth and of the square cross-section steel rod is formed in coil shape of different pitch. T he developed bolt prototypes have been tested underground in the G-11 section of the Rudna mine. Results of the pull-out tests, involving different bolts’ shapes and different sliding materials set on the rockbolts’ rods, have proved those bolts’ efficiency as an element of the ductile support system.

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Authors and Affiliations

Witold Pytel
Piotr Mertuszka
Krzysztof Szeptun
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Abstract

The article is the result of a project aimed at developing and implementing a design of composite accessories for support in excavations located in underground hard coal mines. The research team verified the possibility of using elements made of prefabricated composite structural profile as an alternative to steel and reinforced concrete lining elements used to improve support’s stability and protect against rockfall.
This paper includes a research experiment on the possibilities of using a composite C-profile element as lining made in the pultrusion technology with a longitudinal position of the roving. The prefabricated structural profiles were adapted to the function by designing seatings for fitting the flanges for arch support’s V-profiles. Prototypes of these elements were subjected to bench tests in compliance with the guidelines for testing mesh linings. In addition, computer simulations using the finite element method were carried out.
The values obtained during the tests were compared with the requirements for lightweight mesh and included the Polish standard PN-G-15050 and reinforced A-type concrete lining defined in the standard ­PN-G-06021. The team determined the areas where material strength exceeded and the structure was damaged. Despite the limited quantity of laboratory tests and lack of field tests in actual mining conditions, it was possible to address the argument of the research and determine whether it is possible to use C-profile made in the pultrusion technology as a lining element.
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Bibliography

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[2] PN-G-06021:1997 Obudowa górniczych wyrobisk korytarzowych. Okładziny żelbetowe.
[3] M. Rotkegel. Wpływ sposobu montażu siatek okładzinowych na ich pracę. Przegląd Górniczy 70 (3), 79-85 (2014).
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[5] L . Nickels, The future of pultrusion. Reinf. Plast. 63 (3), 132-135 (2019). DOI: https://doi.org/10.1016/j.repl.2019.01.003
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[7] M. Grodzicki, M. Rotkegel, The concept of modification and analysis of the strength of steel roadway supports for coal mines in the Soma Basin in Turkey. Studia Geotechnica et Mechanica 40 (1), 38-45 (2018). DOI: https://doi.org/10.2478/sgem-2018-0006
[8] G .I. Gayko, M. Rotkegel, Issliedowanija niesuszcziej sposobnosti arocznoj kriepi pri razlicznych wariantach nagrużienia. Ugoł Ukrainy 2, 45-47 (2003).
[9] P. Horyl, R. Snuparek, P. Marsalek, K. Pacześniowski, Simulation of laboratory tests of steel arch support. Arch. Min. Sci. 62 (1), 63-176 (2017). DOI: http://doi.org/10.1515/amsc-2017-0012455
[10] H. Filcek, J. Walaszczyk, A. Tajduś, 1994. Metody komputerowe w geomechanice górniczej. Śląskie Wydawnictwo Techniczne (1994).
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[13] E. Rusiński, Metoda elementów skończonych. System COSMOS/M. Wydawnictwo Komunikacji i Łączności (1994).
[14] A. Pytlik. Tests of steel arch and rock bolt support resistance to static and dynamic loading induced by suspended monorail transportation. Studia Geotechnica et Mechanica 41 (2), 81-92 (2019). DOI: https://doi.org/10.2478/sgem-2019-0009
[15] A. Pytlik. Comparative bench testing of steel arch support systems with and without rock bolt reinforcements. Arch. Min. Sci. 64 (4), 747-764 (2019). DOI: http://doi.org/10.24425/ams.2019.131064
[16] PN-G-15022:2018-11 Odrzwia podatne z kształtowników korytkowych – Wymagania wytrzymałościowe i badania.
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Authors and Affiliations

Marek Rotkegel
1
ORCID: ORCID
Jerzy Korol
1
ORCID: ORCID
Dagmara Sobczak
1
ORCID: ORCID

  1. Central Mining Institute, Plac Gwarków 1, 40-166, Katowice, Poland
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Abstract

This article focuses on the difficulties in ensuring longwall stability resulting from the wrong geometric form of the structure of powered support sections. The authors proved, based on the in-situ measurements and numerical calculations, that proper cooperation of the support with the rock mass requires correct determination of the support point for the hydraulic legs along the length of the canopy (ratio), as well as the inclination of the shield support of the section of the powered roof support. The lack of these two fundamental elements may lead to roof drops that directly impact the production results and safety of the people working underground. Another matter arising from the incorrect geometric form of the construction are the values of forces created in the node connecting the canopy with the caving shield, which can make a major contribution to limit the practical range of the operational height of the powered roof support (due to interaction of powered support with rockmass) in terms of the operating range offered by the manufacturer of the powered support. The operating of the powered roof support in some height ranges may hinder, or even in certain cases prevent, the operator of powered support, moving the shields and placing them with the proper geometry (ensuring parallelism between the canopy and the floor bases of the section).

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Authors and Affiliations

Sylwester Rajwa
ORCID: ORCID

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