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Number of results: 32
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Abstract

An analysis of the impact of mining with caving on the surface shows that a type of rock mass strata seems to be one of the critical factors affecting the process. Correlating the values of mining-induced surface deformation with the rock mass structure and the state of its disturbance is of crucial importance. Therefore, if other mining conditions are left unaffected, then those factors exert the key influence on a course and distribution of subsidence and rock mass deformation. A proper description of rock mass type and properties also seems rational for a proper determination of prediction parameters, especially in the case of a multi-seam coal mining, and/or the exploitation carried out at considerable depths. A general outcome of the study discussed in this paper is the development of the methodology and model practices for determining the rock mass type and, as a result, for selecting the optimal values of parameters for predicting the values of surface subsidence in relation to particular geological and mining conditions. The study proves that the type of rock mass may be described by such factors as the influence of overburden strata, the influence of Carboniferous layers, the disturbance of rock mass and the depth of exploitation.
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Authors and Affiliations

Katarzyna Kryzia
Tadeusz Majcherczyk
Zbigniew Niedbalski
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Abstract

The aim of the article is to present the selected results of analytical investigations concerning

possible directions of reducing the unit production costs in the mining company together with some

results of practical calculations. The investigations emphasize the role of the rate of utilising the

production capacity leading to reducing the unit production costs. The main component having an

essential influence on the unit production costs are the fixed unit costs. Two basic indices of a crucial

meaning for searching for possibilities leading to decreasing the unit production costs are assumed.

The first index (w1) is a measure of the rate of utilising the production capacity, the second one (w2)

concerns the fixed costs coincided with the unit of the production capacity. Theoretical considerations

concerning the mathematical modelling of the unit production costs as the values depending on the

rate of utilising the production capacity and the fixed costs coincided with the production capacity

unit, are presented in the first part of the paper. The rationalisation criteria of the mine unit production

costs are formulated. These criteria can constitute the elements of restructuring program for the mining

company. The calculation example with the use of the practical input data shows the impact of the

rate of utilising the production capacity on the mine unit production costs. In the example two variants

of annual working time are taken into account. Results of appropriate calculations are presented and

analysed in an aspect of reducing unit costs of production as a result of increasing rate of utilising the

mine production capacity.

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Authors and Affiliations

Roman Magda
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Abstract

The subject of the research presented in this paper were financial results of mining industry enterprises (PKD 5 – P olish C lassification of A ctivity – “Mining of coal and lignite”) in 2007–2019. The research was conducted using relative and absolute financial measures, forming an extensive and coherent set of features characterizing their financial condition. The purpose was to measure and evaluate the efficiency of examined enterprises operation, considered as an attribute of development as well as factors describing and determining it. This evaluation was made against the background of ongoing restructuring processes taking into account their potential effects.

The article presents the course of the process of adapting P olish hard coal mining to market economy conditions after 1989. The process can be conventionally divided into several periods. The scope and intensity of changes in the mining industry followed the subsequent government programs for mining industry restructuring.

The lignite mining has not implemented any specific restructuring programs. The remedy processes were mainly related to organizational and ownership changes.

In relation to operation efficiency and value creation three turning points in the development path of enterprises were highlighted – 2011, 2015 and 2017, while the period of strong deterioration of results occurred in 2011–2015. I t was proved that restructuring processes did not affect the operating return on sales. However, there was a strong relation between changes in economic conditions on the coal market (prices) and the accumulation rate.

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Authors and Affiliations

Eugeniusz Jacek Sobczyk
Jarosław Kaczmarek
Kamil Fijorek
Michał Kopacz
ORCID: ORCID
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Abstract

United Nations Framework Convention on Climate Change obliges member countries to make an inventory of greenhouse gases emission and, among others, an inventory of fugitive emission from coal mining system. To comply with this obligation, basing on 1992 data. Poland has evaluated so-called "emission factors" for identified sources of methane emission. According to IPCC/OECD guidelines, the emission factors multiplied by coal output allow simple evaluation of methane emission. Since the time when the emission factors were evaluated in 1994, coal industry in Poland has undergone major organisational and technical changes. At the same time significant development of basic knowledge on geology of methane in coal-bearing strata have occurred. Both these facts make the emission factors evaluated earlier inaccurate. A wide range of research indispensable for accurate evaluation of new emission factors is described in the paper. It is also recommended in the paper that by the time the research results are known, the improved emission factors. which take into account organisational changes of mining industry should be used. Methane emission from coal mining system in 1999 evaluated using those emission factors equals 527,889 Gg.
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Authors and Affiliations

Lidia Gawlik
ORCID: ORCID
Ireneusz Grzybek
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Abstract

Geodesic measurements of mining area deformations indicate that their description fails to be regular,

as opposed to what the predictions based on the relationships of the geometric-integral theory suggest.

The Knothe theory, most commonly applied in that case, considers such parameters as the exploitation

coefficient a and the angle of the main influences range tgβ, describing the geomechanical properties of the

medium, as well as the mining conditions. The study shows that the values of the parameters a = 0.8 and

tgβ = 2.0, most commonly adopted for the prediction of surface deformation, are not entirely adequate in

describing each and every mining situation in the analysed rock mass. Therefore, the paper aims to propose

methodology for determining the value of exploitation coefficient a, which allows to predict the values

of surface subsidence caused by underground coal mining with roof caving, depending on geological and

mining conditions. The characteristics of the analysed areas show that the following factors affect surface

subsidence: thickness of overburden, type of overburden strata, type of Carboniferous strata, rock mass

disturbance and depth of exploitation. These factors may allow to determine the exploitation coefficient a,

used in the Knothe theory for surface deformation prediction.

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Authors and Affiliations

Katarzyna Kryzia
Tadeusz Majcherczyk
Zbigniew Niedbalski
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Abstract

The paper analyzes the impact of potential changes in the price relation between domestic and imported coal and its influence on the volume of coal imported to Poland. The study is carried out with the application of a computable model of the Polish energy system. The model reflects fundamental relations between coal suppliers (domestic coal mines, importers) and key coal consumers (power plants, combined heat and power plants, heat plants, industrial power plants). The model is run under thirteen scenarios, differentiated by the ratio of the imported coal price versus the domestic coal price for 2020–2030. The results of the scenario in which the prices of imported and domestic coal, expressed in PLN/GJ, are equal, indicate that the volume of supplies of imported coal is in the range of 8.3–11.5 million Mg (depending on the year). In the case of an increase in prices of imported coal with respect to the domestic one, supplies of imported coal are at the level of 0.4–4.1 million Mg (depending on the year). With a decrease in the price of imported coal, there is a gradual increase in the supply of coal imports. For the scenario in which a 30% lower imported coal price is assumed, the level of imported coal almost doubles (180%), while the supply from domestic mines is reduced by around 28%, when compared to the levels observed in the reference scenario. The obtained results also allow for the development of an analysis of the range of coal imports depending on domestic versus imported coal price relations in the form of cartograms.

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Authors and Affiliations

Jacek Kamiński
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Abstract

The research of development capabilities is a fundamental of strategic issues, which has to be taken into consideration by coal mines. This is particularly difficult in the current environment, which is determined by its crisis situation. In such conditions, it is necessary to take difficult decisions, and serious, strategic challenges into account, which allow for the crisis to be overcome, for the renewal and economic effectiveness of the operation of these coal mines, which have potential to grow, and closing the coal mines, which have not potential to grow. Due to the effects of such decisions, which concern not only coal mines but also the Silesian region, it is essential to prepare information to support them and promote rational choices. This is related to the issue of research for development possibilities. The article presents considerations related to the subject of research for development possibilities of coal mines in a crisis situation. Taking the results of literature study into account, the model of research process was developed, and identified the research issues concerning the following:

- the identification of external factors which determine the possibility of development of the Polish mines and drawing a schedule of their changes in the future,

- the identification of internal factors which determine the possibility of development of the Polish mines,

- developing a way for the assessment of the development potential of the coal mines, to show appropriate strategic options and action programmes for these options,

- determining possible strategic options and corresponding schedules, appropriate for the specific nature of the mines.

The proposition of their solutions, which were obtained in the process of using the specific methods and research tools, allowed the guidelines in terms of research of development capabilities of coal mines to be presented.

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Authors and Affiliations

Jolanta Bijańska
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Abstract

The purpose of the study was determining of degree of contamination of soil cover as a result of disposing of different industrial wastes and comparison of the soil quality with quality of soils and the grounds described in standards in relation to the reclamation works carried out on the dump. Analysed waste dump belongs to the sparse objects of this type in the Upper Silesian Coal Basin, where both coal mining wastes as well as flying ashes occur.
During investigations there was done a collection of 9 soil samples around the dump using Egner`s cane from the depth of 30 cm. The content of heavy metals was determined (Cd, Co, Cr, Cu, Ni, Pb, Zn) using method of emission spectrometry (ICP-AES) and phase composition studies using the X-ray diffraction method (XRD ).
Obtained results enabled determination of impact of disposed wastes on the degradation of pedosphere of studied area, which represents III group of fallow lands. The contents of heavy metals in soil samples vary in wide spectrum, but do not exceed permissible content of metals and metalloids for the aforementioned soil group. The highest concentrations reaches iron (average content 0,6%), while concentrations of other elements do not exceed 0.02%. In the mineral composition of soil samples the dominant components are typical for soils in the area of post-mining dumps, i.e. quartz, feldspars, clay minerals, represented by kaolinite and illite. The presence of muscovite with a share of < 5% was also found. Minerals from the carbonate group – calcite (< 3.5%) and dolomite (< 0.3%) occur rarely. In the investigated samples there was identified presence of mullite, component typical for wastes coming from energy sector.
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Authors and Affiliations

Marek Marcisz
1
ORCID: ORCID
Zdzisław Adamczyk
1
ORCID: ORCID
Łukasz Gawor
1
ORCID: ORCID
Katarzyna Nowińska
1
ORCID: ORCID

  1. Silesian University of Technology, Gliwice, Poland
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Abstract

Petřvald is a typical mining town in the Czech part of the Upper Silesian Basin. Since the Petřvald sub-basin is limited by significant tectonic structures, its development was to a great extent independent from other areas of the basin and can serve as an example of the influence of the geological structure on the development of mining and residential communities. In the first phase of mining development (ca 1830 to 1844) first claims begin to occur in the area. Thick coal seams were available in shallow depths. Due to missing railway connection, the demand for coal was not very large and the village economy was focused on agriculture. In the second phase (1844 to 1871), the first underground mines start to operate in the area. They were situated in favorable areas with thin overburden. Also, the connection to the railway improved the sale opportunities and a significant share of the local population worked in the mines. The third phase of mining (1871 to 1963) brought still increasing demand for coal, which resulted in establishing new coal mines in geologically less favorable areas (thicker overburden, water-bearing horizons). From the 1930s to the end of the 1950s the extraction peaked, which coincided with the urbanistic and cultural climax. New housing was provided for miners and their families by the companies. The final stage of mining development (1963 to 1998) is connected with the steady decline of production and phase-out of mining. The reason was a lack of economically recoverable coal reserves connected to unfavorable geological conditions. We conclude that the results of studies concerning specific geological parameters of coal deposits can be used for more detailed analyses regarding the development of urbanism, or to explain its causes.

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Authors and Affiliations

Martin Sivek
Jakub Jirásek
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Abstract

There was done an inventarization of 41 coal mining dumping grounds, gathering waste material from 27 mines. Considering the fact, that five mines belong to multi-motion plants the research comprised 32 hard coal deposits. Source data with localization of particular dumps have been obtained from archival materials from the mines and municipalities, in the boundaries where the dumps occur as well as free accessible published materials (books, scientific papers). The data have been verified, in the beginning on the basis of topographical maps, orthophotomaps and aerial photographs and then, after vision done during field works they have been drawn on the topographic base, what resulted in creating the map of post-mining dumping grounds. Valorisation of coal mining waste dumps, using already repeatedly presented method, included defining of: name of the dump, coal mine from where the wastes come from, state of the dump, surface of the dump, type of technical and biological reclamation, accessibility of the object, possibilities of recovery of coal and the results have been drawn on the map. On the basis of collected and elaborated data there was done an attempt of defining of potential possibilities of recovery of coal from the dumps and connecting of coal quality in exploited deposits and coal content in waste material. The results showed that in spite of initial information that the majority of the dumps comprise potential objects of coal recovery of coal from waste material, eventually only in some cases (thirteen objects) the recovery seems to be economically justified.

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Authors and Affiliations

Marek Marcisz
ORCID: ORCID
Krystian Probierz
Łukasz Gawor
ORCID: ORCID
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Abstract

The article presents the methodology for assessing the longevity of hard coal mines. Based on international experts’ assessments, important criteria for determining mine viability have been presented. The results refer to Polish coal mines in the area of the Upper Silesian Coal Basin, however, the methodology itself can be applied to other geological and mining conditions of mines elsewhere.

The results of structural analyses carried out using the MICMAC method for factors related to the mining geo-environment that may determine the longevity of individual hard coal mines are presented. The analyses were based on the results of expert surveys carried out using the Delphi method. The experts participating in the survey came from various countries and had extensive experience related to work or cooperation with hard coal mining. The criterion factors examined were assigned to two systems (groups) for which structural analysis was performed. The first group includes factors related to the level of exploitation hampering, while the second group includes factors related to hard coal quality and the availability of resources. As a result of the analyses the following were determined: the key factors which have the most significant influence on the system, result and goal factors, factors affecting the system and autonomous factors which have little effect on the system.

The obtained results allowed to determine which factors should be taken into account in the process of determining the longevity of a hard coal mine.

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Authors and Affiliations

Aleksander Frejowski
Józef Kabiesz
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Abstract

Coal mining tends to face increasing stress and gas conditions when it extends to deeper levels. The mining-induced high stress and gas pressure concentrations often result in gasogeodynamic phenomena such as rock bursts and coal & gas outbursts. Over the last decades, these gasogeodynamic events have been observed more often in the Upper Silesian Coal Basin, Poland. With the increasing mining depth, these hazards not only become a serious safety risk but also represent a significant challenge for coal mining. In order to eliminate future hazards and improve safety in underground coal mines, it is necessary to apply particular methods for the prevention and mitigation of possible hazards during mining operations. Inaction or incorrect use of preventive measures may lead to gasogeodynamic events, which may result in accidents and material losses, thereby affecting the mine’s economic performance. Several coal mines operated by Jastrzębska Spółka Węglowa S.A. (JSW group), such as Pniówek, Budryk and Zofiówka coal mines have been identified as the area most prone to rock bursts as well as coal and gas outburst. Generally, the longwall panels often experience a high degree of these mining hazards. Therefore, the main aim of this research is to examine and optimise the possibility of application of prevention methods in order to reduce the frequency and scale of dangerous gasogeodynamic phenomena such as coal and gas outburst. As a main part, the field testing of the selected preventive methods that were conducted in the JSW coal mines. Based on the obtained results, the possibility of application of an optimal method for the prevention and control of coal and gas outburst in the geo-mining conditions of the JSW coal mines was discussed. The research results could be an example for other coal mines in mine planning and designing in the gasogeodynamic (coal and gas outburst) hazard-prone conditions.
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Authors and Affiliations

Phu Minh Vuong Nguyen
1
ORCID: ORCID
Piotr Litwa
1
ORCID: ORCID
Marek Przybylski
2
ORCID: ORCID

  1. Central Mining Institute, Department of Extraction Technologies, Rockburst and Risk Assessment, 1 Gwarków Sq., 40-166 Katowice, Poland
  2. Jastrzębska Spółka Węglowa S.A., Pniówek Coal Mine, 18 Krucza st. 43-250, Pawłowice, Poland
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Abstract

The article presents three German-located case studies based on stochastic methods founded by the theory proposed by Knothe and the development of the ‘Ruhrkohle method’ according to Ehrhardt and Sauer. These solutions are successfully applied to predict mining-induced ground movements. The possibility of forecasting both vertical and horizontal ground movements has been presented in the manuscript, which allowed for optimization mining projects in terms of predicted ground movements.
The first example presents the extraction of the Mausegatt seam beneath the district of Moers-Kapellen in the Niederberg mine. Considering, among others, the adaption of the dynamic impact of the underground operations to the mining-induced sensitivity of surface objects, the maximum permissible rate of the face advance has been determined.
The second example presents the extraction of coal panel 479 in the Johann seam located directly in the fissure zone of Recklinghausen-North. Also, in this case, the protection of motorway bridge structure (BAB A43/L225) to mining influences has been presented. The Ruhrkohle method was used as a basis for the mathematical model that was developed to calculate the maximum horizontal opening of the fissure zone and the maximum gap development rate.
Part of the article is dedicated to ground uplift due to rising mine water levels. Although it is not the main factor causing mining-related damage, such movements in the rock masses should also be predicted. As the example of the Königsborn mine, liquidated by flooding, shows stochastic processes are well suited for predicting ground uplift. The only condition is the introduction of minor adjustments in the model and the use of appropriate parameters.
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Authors and Affiliations

Anton Sroka
1
ORCID: ORCID
Stefan Hager
2
ORCID: ORCID
Rafał Misa
1
ORCID: ORCID
Krzysztof Tajduś
1
ORCID: ORCID
Mateusz Dudek
1
ORCID: ORCID

  1. Strata Mechanics Research Institute, Polish Academy of Science, Kraków, Poland
  2. RAG Aktiengesellschaft, Im Welterbe 10, 45141 Essen, Germany
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Abstract

The role of the hard coal mining sector in ensuring energy security of the country has been presented in the paper. An analysis of its current status was made based on the results obtained by the sector in 2017. Moreover, the determinants which are the precondition for further sustainable and efficient operation in the years to come have been defined.

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Authors and Affiliations

Antoni Tajduś
ORCID: ORCID
Marian Turek
ORCID: ORCID
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Abstract

The paper investigates the competitiveness of the Polish hard coal mining sector as a fuel source for heat and power generation. The main objective of the study is to make a quantitative assessment of the impact of the price relationship between domestic and imported steam coal on the consumption of domestic fine coal in the Polish heat and power generation sector. For this purpose, a long-term mathematical model of the Polish steam coal market is employed and scenarios that mimic the relationship between domestic and imported steam coal prices is developed. The following results are analysed:

- the volume of total domestic steam coal consumption under the scenarios analysed,

- the absolute difference in domestic steam coal consumption under the scenarios analysed in comparison with the scenario 0%,

- the total imported and domestic steam coal consumption in the period analysed.

In addition, the results were depicted in cartograms in order to present the distribution of domestic and imported coal consumption in the various regions of Poland.

The results of the study indicate that the supply of steam coal in Poland can be completely covered by domestic mines when the price of domestic coal is from –40% to –20% lower than that of imported coal. For the remaining scenarios, the consumption of imported coal increases and reaches its highest value in the scenario +40%, in which imported coal covered of 71% of total steam coal consumption in Poland over the period.

The conclusions presented in this paper provide valuable findings and policy insights into the competitiveness of domestic mines and management of domestic production both in Poland and other countries in which power generation systems are mostly dominated by coal.

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Authors and Affiliations

Przemysław Kaszyński
ORCID: ORCID
Aleksandra Komorowska
ORCID: ORCID
Marcin Malec
ORCID: ORCID
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Abstract

The new legislative provisions, regulating the solid fuel trade in Poland, and the resolutions of

provincial assemblies assume, inter alia, a ban on the household use of lignite fuels and solid fuels

produced with its use; this also applies to coal sludge, coal flotation concentrates, and mixtures

produced with their use. These changes will force the producers of these materials to find new

ways and methods of their development, including their modification (mixing with other products

or waste) in order to increase their attractiveness for the commercial power industry. The presented

paper focuses on the analysis of coal sludge, classified as waste (codes 01 04 12 and 01 04 81)

or as a by-product in the production of coals of different types. A preliminary analysis aimed at

presenting changes in quality parameters and based on the mixtures of hard coal sludge (PG SILESIA)

with coal dusts from lignite (pulverized lignite) (LEAG) has been carried out. The analysis

of quality parameters of the discussed mixtures included the determination of the calorific value,

ash content, volatile matter content, moisture content, heavy metal content (Cd, Tl, Hg, Sb, As, Pb,

Cr, Co, Cu, Mn, Ni, and W), and sulfur content. The preliminary analysis has shown that mixing

coal sludge with coal dust from lignite and their granulation allows a product with the desired quality

and physical parameters to be obtained, which is attractive to the commercial power industry.

Compared to coal sludge, granulates made of coal sludge and coal dust from lignite with or without

ground dolomite have a higher sulfur content (in the range of 1–1.4%). However, this is still an

acceptable content for solid fuels in the commercial power industry. Compared to the basic coal

sludge sample, the observed increase in the content of individual toxic components in the mixture

samples is small and it therefore can be concluded that the addition of coal dust from lignite or carbonates

has no significant effect on the total content of the individual elements. The calorific value

is a key parameter determining the usefulness in the power industry. The size of this parameter for

coal sludge in an as received basis is in the range of 9.4–10.6 MJ/kg. In the case of the examined

mixtures of coal sludge with coal dust from lignite, the calorific value significantly increases to

the range of 14.0–14.5 MJ/kg (as received). The obtained values increase the usefulness in the

commercial power industry while, at the same time, the requirements for the combustion of solid

fuels are met to a greater extent. A slight decrease in the calorific value is observed in the case of

granulation with the addition of CaO or carbonates. Taking the analyzed parameters into account,

it can be concluded that the prepared mixtures can be used in the combustion in units with flue gas

desulfurization plants and a nominal thermal power not less than 1 MW. At this stage of work no

cost analysis was carried out.

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Authors and Affiliations

Beata Klojzy-Karczmarczyk
Marek Wiencek
Janusz Mazurek
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Abstract

This article presents the use of a multi-criterion Analytic Hierarchy Process (AHP) method to assess

geological and mining condition nuisance in longwall mining operations in selected coal mines in Poland.

For this purpose, a methodology has been developed which was used to calculate the operational nuisance

indicator (WUe) in relation to the cost of mining coal in individual longwalls. Components of the aggregate

operational nuisance indicator include four sub-indicators: the natural hazards indicator (UZN), an

indicator describing the seam parameters (UPZ), an indicator describing the technical parameters (UT)

and an environmental impact indicator (UŚ). In total, the impact of 28 different criteria, which formed

particular components of the nuisance indicators were analysed. In total 471 longwalls in 11 coal mines

were analysed, including 277 longwalls that were mined in the period of 2011 to 2016 and 194 longwalls

scheduled for exploitation in the years 2017 to 2021.

Correlation analysis was used to evaluate the relationships between nuisance and the operating costs

of longwalls. The analysis revealed a strong correlation between the level of nuisance and the operating

costs of the longwalls under study. The design of the longwall schedule should therefore also take into

account the nuisance arising from the geological and mining conditions of the operations. Selective

operations management allows for the optimization of costs for mining in underground mines using the

longwall system. This knowledge can also be used to reduce the total operating costs of mines as a result

of abandoning the mining operations in entire longwalls or portions of longwalls that may be permanently

unprofitable. Currently, underground mines do not employ this optimization method, which even more

emphasizes the need for popularizing this approach.

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Authors and Affiliations

Eugeniusz Jacek Sobczyk
Michał Kopacz
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Abstract

This article discusses the question, to what extent the late and post- socialist transformation in Poland can be considered a key stage in the decline of industrial modernity. Setting out from the premise that state socialism constituted a paradigmatic version of industrial or high modernity, it addresses the major discursive rupture that preceded the regime change of 1989: While the workers’ mass movement of Solidarity had embraced political and social imagina-ries typical of industrial modernity in 1980/81, these came to be re-placed by new socio-economic and cultural frameworks by the end of the 1980s. By outlining the spectacular rise of informal trading, as well as the Polish and transnational input into the promotion of grassroot capitalism, the article indicates how Poland’s late and post-socialist transformation was intrinsically linked to the down-fall of industrial modernity and reflects on the historiographical po-tential of this approach.
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Authors and Affiliations

Florian Peters
ORCID: ORCID
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Abstract

The new legislative provisions, regulating the trade in solid fuels in our country, draw attention to the need to develop and improve methods and methods of managing hard coal sludge. The aim of the work was to show whether filtration parameters (mainly the permeability coefficient) of hard coal sludge are sufficient for construction of insulating layers in landfills at the stage of their closing and what is the demand for material in the case of such a procedure. The analysis was carried out for landfills for municipal waste in the Opolskie, Śląskie and Małopolskie provinces. For hard coal sludge, the permeability coefficient values are in the range of 10–8–10–11 m/s, with the average value of 3.16 × 10–9 m/s. It can be concluded that this material generally meets the criteria of tightness for horizontal and often vertical flows. When compaction, increasing load or mixing with fly ash from hard coal combustion and clays, the achieved permeability coefficient often lowers its values. Based on the analysis, it can be assumed that hard coal sludge can be used to build mineral insulating barriers. At the end of 2016, 50 municipal landfills were open in the Opolskie, Śląskie and Małopolskie Provinces. Only 36 of them have obtained the status of a regional installation, close to 1/3 of the municipal landfill are within the Major Groundwater Basin (MGB) range. The remaining storage sites will be designated for closure. Assuming the necessity to close all currently active municipal waste landfills, the demand for hard coal sludge amounts to a total of 1,779,000 m3 which, given the assumptions, gives a mass of 2,704,080 Mg. The total amount of hard coal sludge production is very high in Poland. Only two basic mining groups annually produce a total of about 1,500,000 Mg of coal sludge. The construction of insulating layers in landfills of inert, hazardous and non-hazardous and inert wastes is an interesting solution. Such an application is prospective, but it will not solve the problem related to the production and management of this waste material as a whole. It is important to look for further solutions.

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Authors and Affiliations

Beata Klojzy-Karczmarczyk
Jarosław Staszczak
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Abstract

Significant quantities of coal sludge are created during the coal enrichment processes in the mechanical processing plants of hard coal mines (waste group 01). These are the smallest grain classes with a grain size below 1 mm, in which the classes below 0.035 mm constitute up to 60% of their composition and the heat of combustion is at the level of 10 MJ/kg. The high moisture of coal sludge is characteristic, which after dewatering on filter presses reaches the value of 16–28% (Wtot r) (archival paper PG SILESIA). The fine-grained nature and high moisture of the material cause great difficulties at the stage of transport, loading and unloading of the material. The paper presents the results of pelletizing (granulating) grinding of coal sludge by itself and the piling of coal sludge with additional material, which is to improve the sludge energy properties. The piling process itself is primarily intended to improve transport possibilities. Initial tests have been undertaken to show changes in parameters by preparing coal sludge mixtures (PG SILESIA) with lignite coal dusts (LEAG). The process of piling sludge and their mixtures on an AGH laboratory vibratory grinder construction was carried out. As a result of the tests, it can be concluded that all mixtures are susceptible to granulation. This process undoubtedly broadens the transport possibilities of the material. The grain composition of the obtained material after granulation is satisfactory. Up to 2 to 20 mm granules make up 90–95% of the product weight. The strength of the fresh pellets is satisfactory and comparable for all mixtures. Fresh lumps subjected to a test for discharges from a height of 700 mm can withstand from 7 to 14 discharges. The strength of the pellets after longer seasoning, from the height of 500 mm, shows different values for the analyzed samples. The values obtained for hard coal sludge and their blends with brown coal dust are at the level from 4 to 5 discharges. The strength obtained is sufficient to determine the possibility of their transport. At this stage of the work it can be stated that the addition of coal dust from lignite does not cause the deterioration of the material’s strength with respect to clean coal sludge. Therefore, there is no negative impact on the transportability of the granulated material. As a result of mixing with coal dusts, it is possible to increase their energy value (Klojzy-Karczmarczyk at al. 2018). The cost analysis of the analyzed project was not carried out.

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Authors and Affiliations

Jacek Feliks
Beata Klojzy-Karczmarczyk
Marek Wiencek
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Abstract

The paper presents the application of the Analytic Hierarchy Process technique to evaluate and choose the best alternative for acquiring hard coal for energy purposes by a potential Investor operating in the mining and energy sector. Six different sources supposed to provide hard coal were analysed, each of which might ensure a secure and independent supply of the material to the newly built coal-fired power plant. When choosing the best decision alternative, the positive and negative impacts of alternatives were considered through the BOCR analysis: benefits (B), opportunities (O), costs (C) and risks (R) analysis. For this purpose, 4 independent hierarchical models were developed. Different models have the same decision alternatives assessed, but they differ in criteria used to develop the models. In each of the models, in accordance with the AHP rules, were calculated final, global weights for the alternatives being assessed. Showing the best alternative was possible by applying the multiplicative formula (B ź O)/(C ź R), which value was used to rank and choose the best alternative from all assessed ones. The best decision alternative is the alternative where the (B ź O)/(C ź R) ratio is the highest.

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Authors and Affiliations

Eugeniusz J. Sobczyk
Aldona Wota
Stanisław Krężołek
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Abstract

Because of the value of time, investors are interested in obtaining economic benefits rather early and at a highest return. But some investing opportunities, e.g. mineral projects, require from an investor to freeze their capital for several years. In exchange for this, they expect adequate remuneration for waiting, uncertainty and possible opportunities lost. This compensation is reflected in the level of interest rate they demand. Commonly used approach of project evaluation – the discounted cash flow analysis – uses this interest rate to determine present value of future cash flows. Mining investors should worry about project’s cash flows with greater assiduousness – especially about those arising in first years of the project lifetime. Having regard to the mining industry, this technique views a mineral deposit as complete production project where the base sources of uncertainty are future levels of economic-financial and technical parameters. Some of them are more risky than others – this paper tries to split apart and weigh their importance by the example of Polish hard coal projects at the feasibility study. The work has been performed with the sensitivity analysis of the internal rate of return. Calculations were made using the ‘bare bones’ assumption (on all the equity basis, constant money, after tax, flat price and constant operating costs), which creates a good reference and starting point for comparing other investment alternatives and for future investigations. The first part introduces with the discounting issue; in the following sections the paper presents data and methods used for spinning off risk components from the feasibility-stage discount rate and, in the end, some recommendations are presented.

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Piotr W. Saługa
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Abstract

This paper presents the situation of coal mining in Slovakia, focusing on the social-political aspects and environmental aspects of its sustainable development. In recent years, the mining of lignite and brown coal in Slovakia has been closely linked to the production of electricity and heat in the Novaky power plant. Domestic brown coal production covered more than three quarters of demand in the Slovak Republic in the last few years. The sustainability of coal mining in the coming years in Slovakia is closely associated with raw materials reserves, new mining technologies, the development of the Novaky power plant, and the government's commitments to national economic interests through securing the energy supply or state aid. Of course, of these factors must be considered in the context of international obligations, such as those related to climate and environment, particularly air protection.

The three most important Slovak brown coal deposits are located in the Upper Nitra Basin. This territory includes areas in the 5th and 4th degrees of environmental quality, signifying a disturbed and very disturbed environment. Since coal is expected to remain the dominant fuel for electricity generation araund the world, and in particular for many of the countries of Central and Eastern Europe, it is necessary to create conditions for the environmental sustainability of coal mining in the coming years within the context of international obligations. Both the security and the stability of the electricity network in Slovakia and maintaining employment levels in the Upper Nitra region play important roles in this discussion.

Underground coal gasification (UCG) is a newmining technology and a technology for gas recovery in situ.

A comprehensive evaluation of the impacts of underground coal gasification was carried out in addition to summarization of the expected impacts in terms of the significance and distribution of the time period.

Based on a comprehensive assessment of the proposed action, it can be stated that it could bring a socially unacceptable risk to the area, specifically the significant impairment of health or the environment (groundwater and nearby hot springs in Bojnice). The implementation of operations could affect the opulation's health, since the partition is placed in close proximity to residential areas.

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Authors and Affiliations

Erika Skvarekova
Lubica Kozakova
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Abstract

The paper presents multi-criteria optimization method allowing for selection of the best production scenarios in underground coal mines. We discuss here the dilemma between strategies maximizing economic targets and rational resources depletion. Elaborated method combines different geological and mining parameters, structure of the deposit, mine’s infrastructure constrains with economic criteria such as the net present value (NP V), earnings before deducting interest and taxes (EBIT ) and the free cash flows to firm (FCFF). It refers to strategic production planning. Due to implementation of advanced IT software in underground coal mines (digital model, automated production scheduling) we were able to identify millions of scenarios finally reduced to a few – the best ones. The method was developed and tested using data from mine operation “X” (a real project – an example of a coking coal mine located in Poland). The reliability of the method was approved; we were able to identify multiple production scenarios better than the one chosen for implementation in the “X” mine. The final product of the method were rankings of scenarios grouped according to economic decision criteria. The best scenarios reached NP V nearly 50% higher than the Base Case, which held only 52. position out of 60. According to EBIT and FCFF criteria, 10 scenarios achieved results higher than the Base Case, but the percentage differences were very small, below 2 and 4%, respectively. The developed method is of practical importance and can be successfully applied to many other coal projects.

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Authors and Affiliations

Michał Kopacz
ORCID: ORCID
Leszek Malinowski
Sylwester Kaczmarzewski
ORCID: ORCID
Paweł Kamiński

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