Analysis of Methane Hazard Conditions in Mine Headings

One of the most dangerous and the most common hazards in coal mines is methane hazard. This threat is associated with inflammation and/or explosion of methane in the mixture of air. Analysis of the scale of methane hazard allows the selection of such a longwall ventilation system operating, which provides the requisite provisions of the chemical composition of the mine atmosphere, and the required efficiency of methane drainage. The article presents the results of numerical analysis of the flow of the mixture stream of air and methane by the layout of workings of one of the mines. The aim of this study was to analyse the workings and the designation of zones of the ventilation system in question, where there may be dangerous, explosive concentrations of methane. The results are important when taking preventive actions aimed at reducing methane emissions to the external environment in the process of methane drainage

Applying Cfd Model Studies to Determine Zones at Risk of Methane Explosion and Spontaneous Combustion of Coal in Goaves

Underground mining operations are subject to a number of natural hazards. Events resulting from these hazards are difficult to predict, and if they occur, they disrupt the entire mining process and pose a great danger to the crew. Some of the most dangerous include ventilation hazards involving methane explosions and fires caused by the spontaneous combustion of coal. The complex state of the underground environment means that these hazards oftentimes occur simultaneously, making mining conditions even worse. The following paper addresses this issue by developing the methodology for determining areas endangered by methane explosions and spontaneous coal combustion in goaves. The reference to goaves results from the fact that this particular area is most frequently affected by spontaneous coal combustion and the accumulation of dangerous amounts of methane. The developed methodology was based on model tests with the use of the CFD method and data necessary to develop a numerical model. The research encompassed a real longwall in one of the hard coal mines, ventilated with the Y system during its exploitation, which is beneficial in the case of the methane hazard but worsens the safety in terms of the self-ignition of coal. As a result of the conducted research, for the exploitation conditions, dangerous zones were specified due to the potential possibility of methane explosion and self-heating of coal. The basis for determining dangerous zones was the criteria of occurrence of the examined phenomena. In this study, the zones were identified for each of the investigated hazards separately and for their simultaneous occurrence. Thus, the aim of the study, which involved the determination of potentially hazardous zones by applying modern methods of modelling in the mining area, was achieved. The results are an immensely important source of information for activities aimed at improving safety in the studied area in relation to the studied threats

Analyzing Similarities between the European Union Countries in Terms of the Structure and Volume of Energy Production from Renewable Energy Sources

The European Union (EU) countries, as one of the most economically developed regions in the world, are taking increasingly decisive actions to reduce the emission of harmful substances into the natural environment. This can be exemplified by a new climate strategy referred to as “The European Green Deal”. Its basic assumption is that the EU countries will have achieved climate neutrality by 2050. To do so, it is necessary to make an energy transition involving the widest possible use of renewable energy sources (RES) for energy production. However, activities in this area should be preceded by analyses due to the large diversity of the EU countries in terms of economic development, the number of inhabitants and their wealth as well as geographical location and area. The results of such analyses should support the implementation of adopted strategies. In order to assess the current state of the energy sector in the EU and indicate future directions of activities, research was carried out to analyze the structure and volume of energy production from RES in the EU countries. The aim of the study was to divide the EU countries into similar groups by the structure and volume of energy production from RES. This production was compared with the number of inhabitants of each EU country, its area and the value of Gross Domestic Product (GDP). This approach allows a new and broader view of the structure of energy production from RES and creates an opportunity to take into account additional factors when developing and implementing new climate strategies. The k-means algorithm was used for the analysis. The presented analyses and obtained results constitute a new approach to studying the diversified energy market in the EU. The results should be used for the development of a common energy and climate policy and economic integration of the EU countries

Assessing the Level of Innovation of Poland from the Perspective of Regions between 2010 and 2020

The growing and expanding zone of the free-market economy results in increasing competition in the global market, which leads companies to seek and implement solutions that will give them a competitive advantage. The authorities of countries and regions are also increasingly involved in this process, seeing it as an opportunity to develop and build a knowledge-based economy. One of the main factors improving competitiveness and providing opportunities for development is innovation, particularly developed at the local level. For this reason, activities that support research and development of innovation at the regional level are increasingly appreciated and gain greater importance. This article refers to regional innovation in Poland by analyzing its level between 2010 and 2020. The basis of the analysis was 15 selected indicators characterizing three dimensions related to the innovative development of regions, namely innovative capacity, innovative position, and economic development. This assessment was regarded as a multi-criteria problem, for which the CODAS method was used. Its application made it possible to achieve the main objective of this paper, which was to determine the level of innovation of studied regions and, on this basis, to create their ranking. In addition, the evaluation of the level of innovation of the regions for each of the analyzed dimensions was also carried out, and the relationship between the level of economic development and the capacity and innovative position of the regions was specified. The measure for evaluating the level of innovation, for each case studied, was the value of the Hi index, taken as a synthetic measure of regional innovation. The results show that the level of innovation for the regions in Poland varies widely as a function of time as well as the location of these regions. Differences in the dynamics of change and different levels of development of the analyzed dimensions characterizing innovation are evident. The results provide new knowledge in the field of regional development and should be used when creating a regional development strategy for individual regions, Poland, and the EU

Analiza pracy złącza ciernego odrzwi obudowy górniczej przy osiowym ściskaniu i statycznym zginaniu

Tyt. z nagłówka.Bibliogr. s. [120].Dostępny również w formie drukowanej.STRESZCZENIE: W artykule przedstawiona została analiza wytrzymałościowa złącza ciernego odrzwi obudowy chodnikowej przy osiowym ściskaniu i przy statycznym zginaniu. Analizie poddano złącze składające się z dwóch prostych odcinków kształtownika V29 połączonych dwoma strzemionami typu SDO29. Przy statycznym zginaniu rozpatrzone zostały dwa przypadki obciążenia złącza. W pierwszym siła obciążająca działała na złącze zgodnie z PN-91/G-15000/11 poprzez trawersę, a w drugim przypadku siła działa bezpośrednio w środku złącza zgodnie z DIN 21530-4-2003-05. Przedstawione zostały wyniki badań stanowiskowych oraz wyniki analiz numerycznych przeprowadzonych metodą elementów skończonych. Na podstawie przeprowadzonych analiz wyznaczone zostały charakterystyki pracy złącza oraz najbardziej wytężone miejsca poszczególnych elementów złącza ciernego. Przedstawione modele numeryczne stwarzają duże możliwości symulacyjne w zakresie zmienności wartości i szybkości obciążenia jak i zmian konstrukcyjnych analizowanych złączy. SŁOWA KLUCZOWE: obudowa górnicza, złącze cierne. ABSTRACT: In the article friction joints stress analysis of steel frame of road support with axial compression and the static bending are presented. Analyzed joint consisting of two straight sections of Profile V29 combined two types SDO29 stirrups. With static bending two cases of load joint were examined. In the first loading force acted on the joint accordance with PN-91/G-15000/11 through traverse, in the second case the force acts directly in the middle of the connector according to DIN 21530-4-2003-05. The results of position experiments and numerical analysis, carried out by finite elements method, were presented. On the basis of the analysis characteristics of connector work and the most exposed places of particular elements of friction joint have been determined. Presented numerical models are creating great simulation potential in the changeability of the value and the load speed as well as structural changes in the analyzed joints. KEYWORDS: mining support, friction joint

Wstępna analiza pracy połączenia śrubowego w złączu ciernym

Tyt. z nagłówka.Bibliogr. s.[111]Dostępny również w formie drukowanej.STRESZCZENIE: W artykule przedstawione zostały wyniki analizy wytrzymałościowej śrub strzemion pracujących w złączu ciernym odrzwi obudowy górniczej. Analiza objęła wyznaczenie sił osiowych działających w śrubach strzemion złącza ciernego dokręconych wstępnym momentem skręcającym. Siły zostały wyznaczone na podstawie badań stanowiskowych oraz na podstawie analiz numerycznych pracy złączy ciernych poddanych osiowemu ściskaniu oraz statycznemu zginaniu. Badania i analizy zostały przeprowadzone dla złącza składającego się z dwóch prostych odcinków kształtownika V29 połączonych dwoma strzemionami typu SDO29 zgodnie z PN-91/G-15000/11 oraz DIN 21530-4-2003-05. SŁOWA KLUCZOWE: obudowa górnicza, połączenia śrubowe, złącze cierne. ABSTRACT: In the article are presented the results of the stress analysis of the screws stirrups work in friction joint steel arch mining support. Analysis covered the determination of axial forces acting in the stirrup screws connector tighten by initial bending torque. Forces have been designated on the basis of position researches and numerical analysis of connectors work subjected to axial compression and static bending. Researches and analysis have been carried out for the joint consisting of two straight sections of Profile V29 combined two stirrups in accordance with SDO29 type PN-91/G-15000/11 and DIN 21530-4-2003-05. KEYWORDS: mining support, screw connection, friction joint

Wpływ obciążenia dynamicznego na parametry pracy złącza ciernego

Tyt. z nagłówka.Bibliogr. s. [101].Dostępny również w formie drukowanej.STRESZCZENIE: W artykule przedstawiono wyniki badań stanowiskowych złączy ciernych przy ich obciążeniu dynamicznym. Badania polegały na osiowym obciążaniu (ściskaniu) złącza ciernego, na którym spoczywała trawersa, masą swobodnie spadającą z określonej wysokości. Na podstawie przeprowadzonych badań wyznaczono dynamiczne charakterystyki pracy złącza ciernego. Przedstawiają one zależności pomiędzy wartością siły przenoszonej przez złącze w trakcie obciążenia dynamicznego w funkcji czasu. W czasie badań rejestrowano także wartości sił osiowych w śrubach strzemion. Przemieszczenia elementów złącza ciernego rejestrowano przy pomocy kamery szybkoklatkowej, co umożliwiło wyznaczenie także ich prędkości i przyśpieszeń. Przedstawione wyniki badań powinny zostać wykorzystane przy eksploatacji, projektowaniu oraz doborze obudowy podatnej do warunków zagrożenia obciążeniem dynamicznym. SŁOWA KLUCZOWE: obudowa górnicza, złącze cierne, obciążenie dynamiczne. ABSTRACT: The article presents the results of stand tests for friction joints under a dynamic load. The tests consisted of exerting an axial load (compression) on the friction joint on which a traverse was placed with a mass freely falling from a specific height. The dynamic characteristics of a friction joint's work were identified based on the tests carried out. The characteristics determine a variance in the value of the force transmitted by a friction joint during a dynamic load according to time. Variances in the value of axial forces in the clamps joints were also registered during the tests. The displacements of a friction joint's elements were recorded with a highspeed camera which also enabled to determine their speeds and accelerations. The tests results presented should be used in operating, designing and selecting a yield support for the conditions of a dynamic load hazard. KEYWORDS: mining support, friction joint, dynamic load

Adapting the Powered Roof Support to Diverse Mining and Geological Conditions

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

The level of implementing sustainable development goal "Industry, innovation and infrastructure" of Agenda 2030 in the European Union countries: Application of MCDM methods

Research background: Sustainable development of the modern world represents an opportunity to preserve economic growth and technological progress, as well as social development, without limiting the possibilities of this development for past generations. The directions of this development are included in the 17 goals and 169 tasks of the 2030 Agenda for Sustainable Development. The achievement of these goals and the implementation of the adopted tasks is a huge challenge for individual countries and regions. This also applies to the European Union (EU), where economic development is closely linked to environmental protection and social inclusion. Of key importance in this context is Objective 9 of Agenda 2030, and thus its level of implementation in the EU-27 countries is the aim of the research presented in this paper. Purpose of the article: The research involved assessing the level of EU countries in terms of building stable infrastructure, promoting sustainable industrialization and fostering innovation, i.e., the main areas of Goal 9 of Agenda 2030. Methods: The assessment was based on the EU-27 countries' sustainable development index (SDG9) determined with the use of 14 indicators characterizing these areas between 2015-2020. The basis of the developed methodology was a multi criteria decision making approach (MCDM methods). TOPSIS, WASPAS and EDAS methods were used to determine the sustainability index, and the Entropy, CRITIC and standard deviation (SD) methods were used to determine weights for the adopted indicators. In addition, the use of the Spearman's and Kendall's Tau non-parametric tests enabled the analysis of the relationship between the SDG9 index and the basic economic, environmental and energy parameters, as well as the digitalization of the countries under study. Findings & value added: The results show that the EU-27 countries vary widely in terms of implementing Sustainable Development Goal 9 of Agenda 2030 over the analyzed period. Now, the most advanced in this respect are Denmark, Germany, Luxembourg, the Netherlands, Finland, and Sweden. By contrast, substantial problems are found in Bulgaria, Greece, Portugal, and Lithuania. The results also provide an opportunity to trace changes in the value of the designated index in individual countries, and in groups of countries of the "old" and "new" EU. These results significantly enrich the knowledge of the effectiveness of implementing Goal 9 of Agenda 2030 in the EU-27 countries and the relationship between the development of individual countries and sustainable development economy. These findings can also be used to create new EU-27 strategies for sustainable and solidarity-based development of the whole EU. In addition, the results can be helpful to decision-makers as they highlight important indicators related to innovation, industrialization and infrastructure that should be considered when formulating a country's sustainable development strategy. The added value of the study is the research procedure presented, which can be used in analyses on the study of various issues related to sustainable development for other groups of regions

Digitalization of Small and Medium-Sized Enterprises and Economic Growth: Evidence for the EU-27 Countries

Successful implementation of digital solutions in a given region or country significantly depends on the implementation of this process by Small and Medium-Sized Enterprises (SMEs). This problem is very well understood in the European Union, where actions are being taken to accelerate this process and build a sustainable and competitive knowledge-based economy. This article addresses this issue by conducting a study of the digital maturity of SMEs among the EU-27 countries. The aim of the study was to determine the level of digital maturity of SMEs in the EU-27 countries as well as whether and how the economic parameters of individual EU countries affect the process of SME digitalization. The adopted objectives determined the developed research methodology and the applied methods. The research was based on data from the Eurostat database, on the basis of which 11 indicators characterizing technologies and digital solutions identified with the Industry 4.0 concept were specified and adopted for the study. The entropy-based Evaluation based on distance from average solution (EDAS) method was used to assess the EU countries in terms of the level of digital maturity of SMEs, and the Principal Component Analysis (PCA) method was used to analyze similarities between these countries in terms of technologies implemented in SMEs. On the other hand, to determine a relationship between the digital maturity index (digitalization) and the basic economic parameters of the economy, two nonparametric tests (Spearman and Tau Kendall) were utilized. Based on the determined digital maturity index, the EU-27 countries were evaluated in terms of the level of digital maturity of SMEs, dividing them into four groups. The results showed large discrepancies between individual EU-27 countries and between the old (EU-14) and the new (EU-13) EU countries in terms of SMEs digitalization. These results should be widely used to develop a digitalization strategy for the EU economy and policies to improve the degree of digitalization, especially in countries lagging in this area. The universality of the developed methodology creates wide opportunities for its use to study other countries and regions worldwide