The paper presents an analysis of hard coal prices offered at the coal depots in Poland. Coal depots are one of the most popular forms of purchasing coal by Polish households. Prices refer to price offers for cobble coal (grain size: 60–120 mm) and their analysis is performed based on the regions rather than on all Polish provinces. From January 2010 to May 2019, there were two regions that were distinguished in terms of price spread: the S-W region and the N-E region. In the case of the S-W region, the difference between the province with the minimum price (Śląskie Province) and with the maximum price (Dolnośląskie Province since September 2017) ranged from PLN 53–83/ton, and in the N-E region the difference ranged PLN 64–130/ton. In the case of the remaining two regions, prices varied from a few to approximately PLN 80/ton for the N-W region, and from a few to about PLN 40 /ton for the S-E region. In order to determine how the origin of the coal affects its prices (domestic coal, imported coal), the analysis also included cobble coal price offers that are part of the Author’s own database created for several years. In the case of cobble coal from domestic producers, price offers varied betwwen PLN 14–33/GJ, and price offers for imported cobble coal stood varied between PLN 12–32/GJ. The N-E region attracted particular attention as the price offers for imported cobble coal reached a level similar to the offers from the S-W region, i.e. the region closest to Silesian coal mines. Price differentials within provinces belonging to a given region were influenced by the geographical rent. The paper also analyses average selling prices offered by domestic producers for various size grades of steam coal as well as selling prices for imported coal (free-at-frontier price).

This paper deals with issues related to tribological processes occurring as a result of excessive wear of the surface of scraper conveyor components caused by the impact of the mined material created during drilling of development or exploitation galleries. One of the most common types of tribological wear is abrasive wear. W ear tests were carried out for hard coal – based abrasive using dry carbon abrasive and a hydrated mixture with 76 and 58% hard coal. Based on the conducted research, it was established that the effects of wear processes are associated with damage typical of wear mechanisms: micro-scratching and micro-fatigue. For the wear variant in the presence of dry coal abrasive, individual scratches caused by the abrasive grains were observed on the surface of the samples. The main reason for this type of damage was the aggregation of quartz, which is one of the basic components of the mineral substance present in the tested hard coal. When hydrated carbon mixtures were used as an abrasive, the surface of the samples also displayed scratches characteristic of the aggregate quartz. A small part of the carbon abrasive was pressed into the scratches. Under the influence of the wear caused by friction, small depressions were also formed, where coal penetrated. The effect of coal pressing into micro-scratches is related to its plastic properties. T ests of the abrasive conducted after the conclusion of wear tests have shown that under the influence of the local increase in temperature and pressure, the hard coal contained in the abrasive can undergo transformations. In the abrasive transformed under friction, small, but measurable changes in the content of the C element in relation to the initial hard coal sample were exhibited.

Running a business entails various risks which can significantly impact the economic and production results achieved by a given enterprise. One way of hedging certain risks is to use appropriately designed derivatives. This article presents the newest group of these contracts, i.e. swaps, and focuses on how these contracts can be used by Polish mining companies from the hard coal mining sector selling a part of their output on the global market. This article briefly characterises and presents types of swaps as well as the Polish swap market, pioneered by Polski Bank Rozwoju S.A. with the first FX swap of 1992. Since then, other types of transactions have also been included in the offering of domestic banks (assets swaps, cross-currency interest rate swaps). Mining companies producing hard coal have not been active on the swap market yet because of their poor activity on derivative markets. This article proposes a swap as an derivative hedging the hard coal price for a mining company exporting a part of its production to the global market. In the presented example, a mining company, by concluding a forward and an appropriately structured commodity swap, was able to both protect it self from a fall in the price and use additional gains due to prices rising in the global market. Apart from commodity swaps, mining companies can use FX swaps, IRS and other swaps described in the literature and commonly applied in practice by various economic entities, depending on the type of risk that needs hedging. A significant advantage of this kind of contract is that there is no need to freeze funds in security deposits, nor are there fees of other kinds (premiums) like those payable for other derivatives (futures, options).

Coal reserves in the Czech Republic are estimated to be 10 billion tons – hard coal about 37%, brown coal about 60% and lignite 3%. Hard coal is produced in Northern Moravia. In 2017 the production of hard coal was 5.5 million tons. Brown coal is mined in North-Western Bohemia − the production of brown coal in 2017 was 38.1 million tons. Significant quantities of hard coal are exported to: Slovakia, Austria, Germany and Hungary. In accordance with the National Energy Policy, coal will remain the main source of energy in the country in the future, despite the increased use of nuclear energy and natural gas. The government expects that in 2030 energy from coal will account for 30.5% of energy produced. There are five coal companies in the Czech Republic: OKD, a.s., the only hard coal producer and four brown coal mining companies: Severočeské Doly a.s., owned by ČEZ, the largest producer of brown coal, Vršanská uhelná a.s., with coal resources until 2055, Severní energetická a.s. with the largest brown coal reserves in the Czech Republic and Sokolovska uhelná a.s., the smallest mining company extracting lignite. OKD operates coal in two mines Kopalnia Důlní závod 1 – (consists of three mines: ČSA Mine, Lazy Mine, Darkov Mine) and Mine Důlní závod 2 (ttwo mines Sever, Jih). The article also presents a pro-ecological solution for the management of waste heaps after coal enrichment – a plant for the enrichment of coal waste from the Hermanice heap.

Coal combustion processes are the main source of mercury emission to the environment in Poland. Mercury is emitted by both power and heating plants using hard and brown coals as well as in households. With an annual mercury emission in Poland at the level of 10 Mg, the households emit 0.6 Mg. In the paper, studies on the mercury release in the coal and biomass combustion process in household boilers were conducted. The mercury release factors were determined for that purpose. For the analyzed samples the mercury release factors ranged from 98.3 to 99.1% for hard coal and from 99.5% to 99.9% for biomass, respectively. Due to the high values of the determined factors, the amount of mercury released into the environment mainly depends on the mercury content in the combusted fuel. In light of the obtained results, the mercury content in the examined hard coals was 6 times higher than in the biomass (dry basis). Taking the calorific value of fuels into account, the difference in mercury content between coal and biomass decreased, but its content in coal was still 4 times higher. The mercury content determined in that way ranged from 0.7 to 1.7 μg/MJ for hard coal and from 0.1 to 0.5 μg/MJ for biomass, respectively. The main opportunity to decrease the mercury emissions from households is offered by the use of fuels with a mercury content that is as low as possible, as well as by a reduction of fuel consumption. The latter could be obtained by the use of modern boilers as well as by the thermo-modernization of buildings. It is also possible to partially reduce mercury emissions by using dust removal devices.

This study presents the results of concentrations of rare earth elements and yttrium (REY ), uranium (U), and thorium (Th) in ashes from combustion/co-combustion of biomass (20%, 40%, and 60% share) from the agri-food industry (pomace from apples, walnut shells, and sunflower husks) and hard coal. The study primarily focuses on ashes from the co-combustion of biomass and hard coal, in terms of their potential use for the recovery of rare earth elements (REE ), and the identification of the sources of these elements in the ashes. Research methods such as ICP-MS (inductively coupled plasma mass spectrometry), XRD (X-ray diffraction), and SEM -EDS (scanning electron microscopy with quantitative X-ray microanalysis) were used. The total average content of REY in ash from biomass combustion is 3.55–120.5 mg/kg, and in ash from co-combustion, it is from 187.3 to 73.5 mg/kg. The concentration of critical REE in biomass combustion ash is in the range 1.0–38.7 mg/kg, and in cocombustion ash it is 23.3–60.7 mg/kg. In hard-coal ash, the average concentration of REY and critical REY was determined at the level of 175 and 45.3 mg/kg, respectively. In all samples of the tested ashes, a higher concentration of Th (0.2–14.8 mg/kg) was found in comparison to U (0.1–6 mg/kg). In ashes from biomass and hard-coal combustion/co-combustion, the range of the prospective coefficient (Coutl) is 0.66–0.82 and 0.8–0.85, respectively, which may suggest a potential source for REE recovery. On the basis of SEM -EDS studies, yttrium was found in particles of ashes from biomass combustion, which is mainly bound to carbonates. The carriers of REY , U, and Th in ashes from biomass and hard-coal co-combustion are phosphates (monazite and xenotime), and probably the vitreous aluminosilicate substance.

Human-induced climate change is caused by the emission of pollutants into the environment. One of the sources of the formation of harmful compounds is the combustion of solid fuels in heating boilers. These contribute to the occurrence of respiratory and circulatory system diseases, allergies, cancer and developmental disorders in children. In this research, the concentrations of carbon monoxide, nitrogen oxides, sulfur dioxide and hydrocarbons in samples obtained from the combustion of hard coal intended for fuel in household furnaces were measured using an exhaust-gas analyzer equipped with electrochemical sensors. The combustion of test samples was performed using an up-draft research furnace. The results show that the average total concentration of the tested pollutants emitted from the combustion of type 32 and type 33 coal is over 20% lower compared to the emission from the combustion of type 31 coal. Moreover, the concentration of carbon monoxide, the permissible levels of which are regulated by the chimney emission standards, is significantly lower during the combustion of type 32 and type 33 coal compared to the combustion of type 31 coal. Therefore, one of the ways to locally reduce pollutant emission from the combustion of solid fuels in home heating boilers might be the accurate choice of the type of hard coal used for heating. Before the use of coal stoves in households is completely dismissed, local regulations can be introduced to limit emissions in places where air quality indicators are exceeded and improve the health of the population.

The geopolitical situation in Europe has changed dramatically due to the war waged by the Russian Federation in Ukraine. This makes it necessary to become independent from supplies of mineral resources, especially energy from Russia. According to the authors, ensuring Poland’s energy security will require a longer use of coal as the primary energy resource than initially expected. The expected increase in energy demand may cause a negative energy balance in the country. Renewable energy sources dependent on weather conditions cannot with certainty ensure energy security. On the other hand, nuclear requires large financial outlays and a longer time for reactors’ construction. In addition, it has other disadvantages (the problem of waste, environmental impact in the event of a malfunction and the need to import uranium). In these circumstances, coal may be a raw material that meets the economic needs and ensures the energy security of the country.

The aim of the study is to determine the mercury content in hard coal, randomly taken from the USCB and in by-products of hard coal mining (fresh mining waste), i.e. aggregates (gangue) and hard coal sludge and mining waste from the Siersza dump (weathered waste). The 34 samples were intended for analysis. The total mercury content and the amount of mercury leaching from solid samples was determined. The percentage of the leaching form in the total element content, i.e. the level of mercury release from the material (leaching level), was also calculated. The amount of mercury leaching was determined by a static method using a batch test 1:10. The highest possibility of leaching mercury is characterized by weathered waste from the Siersza dump and slightly lower analyzed hard coal from the U pper Silesian Coal Basin (USCB). For hard coal samples, the total mercury content is between 0.0275–0.1236 mg/kg. However, the amount of mercury leaching from coal samples is 0.0008–0.0077 mg/kg. The aggregate is characterized by a higher total mercury content in the finest fraction 0–6 mm, within 0.1377–0.6107 mg/kg and much lower in the 80-120 mm fraction, within 0.0508–0.1274 mg/kg. The amount of elution is comparable in both fractions and amounts to 0.0008–0.0057 mg/kg. Coal sludge has a total mercury content of 0.0937–0.2047 mg/kg. L ow leaching values of 0.0014–0.0074 mg/ kg are also observed. Weathered mining waste has a total mercury content of 0.0622–0.2987 mg/kg. However, leaching values from weathered waste are much higher than from fresh mining waste. This value is 0.0058–0.0165 mg/kg. In the hard coal extracted from U SCB, the leaching level is 4.7% on average. Mining waste is characterized by a large variation in the proportion of mercury leaching form and the differences result from the seasoning time of the samples. Waste or by-products of hard coal production, such as aggregates and coal sludge, show a mercury washout form at an average level of 1.7%. The proportion of leachable form in weathered waste increased strongly to 7.3%. Elution characteristics vary for different groups of materials tested. Factors such as the type and origin of samples, their granulometric composition and the seasoning time of the material are of fundamental importance and demonstrated in the work.

The Polish power generation system is based mostly on coal-fired power plants. Therefore, the coal mining sector is strongly sensitive to changes in the energy sector, of which decarbonization is the crucial one. The EU Emission Trading System (EU ETS) requires power generating companies to purchase European Emission Allowances (EUAs), whose prices have recently soared. They have a direct impact on the cost efficiency of hard coal-fired power generation, hence influence the consumption of hard coal on the power sector. In this context, the objective of this paper is to estimate the hard coal consumption in various regions of Poland under selected forecasts of the EUA price. To investigate this question, two models are employed:

 - the PolPower_LR model that simulates the Polish power generation system,

 - the FSM _LR model that optimizes hard coal supplies.

Three scenarios differentiated by the EUA price are designed for this study. In the first one, the average EUA price from 2014–2017 is assumed. In the second and third, the EUA prices are assumed accordingly to the NPS and the SDS scenario of the World Energy Outlook. In this study we consider only existing, modernized, under construction and announced coal-fired power generation units. The results of the study indicate that regardless of the scenario, a drop in hard coal consumption by power generation units is observed in the entire period of analysis. However, the dynamics of these changes differ. The results of this analysis prove that the volume of hard coal consumption may differ by even 136 million Mg (in total) depending on the EUA prices development scenario. The highest cumulated volume of hard coal consumption is observed in the Opolski, Radomski and Sosnowiecki region, regardless of the considered scenario.

The coal fed to gravity enrichment consists of coals coming from different deposits and exploitation fronts. These coals differ in quality parameters, especially the amount of gangue (stone) changing over time. This results in the instability of work, especially jiggers, which have a relatively low accuracy assessed by probable scattering or imperfection rates. This deteriorates the quality of the concentrate obtained, the quality parameters of which change over time. The improvement of jiggers work would be possible by averaging the feed. This process is practically impossible due to the failure to design such a node during plant construction, which are, in most cases, directly related to the shaft. In the article, the authors propose to solve the process of averaging the feed before directing it to the enrichment process in jiggers by introducing its deshaling in vibratory- air separators of the FGX type.

Coal mining is one of the most important sectors of the Polish industry. It can be said that the coal is a national raw material. This results in Poland being a pioneer in the European Union in terms of coal mining as well as its use in the production of electricity and heat. There are many companies in Poland which have been established and developed around the coal mining industry aimed at coal extracting. The operations of those companies depends on the condition of the mining companies and their cooperation with them: commercial, service and advisory, called referred to as “mining supporting companies”. The article focuses on the results of a survey carried out in mining supporting companies, such as mining machinery and equipment manufacturers, mining-related service companies and mining-related research and development institutions. The authors evaluated the relationship and dependence of those companies on the mining industry. It was assumed that the measure of the mining supporting companies condition is the overall quantity of public related payments contributed to the state budget and local budgets. In the article, the authors raised the problem of the size of losses for public finances, as a result of the significant limitations of financial flows from the mining companies. The surveyed companies are those associated with the Polish Mining Chamber of Industry and Commerce. As a result, the authors prepared conclusions regarding the dependence of the mining supporting companies on the situation of the mining subsector.

The paper presents selected issues related to the development of international coal markets. World consumption of coal dropped for the second year in a row in 2016, primarily due to lower demand from China and the U S. The share of coal in global primary energy consumption decreased to 28%. World coal production accounted to 3.66 billion toe and it was lower by 6.2% when compared to the previous year. More than 60% of this decline took place in China. The decline in global production was more than four times higher than the decrease in consumption. The sufficiency of world resources of coal are estimated at 153 years – that is three times more than the sufficiency of oil and gas resources. After several years of decline, coal prices increased by 77% in 2016. The current spot prices are at the level of $80/t and are close to the 2014 prices. In the European market, after the first half of the year, coal prices reached the level of around 66% higher than in the same period of the last year. The average price in the first half amounted to PLN 12.6/GJ, which is close to the 2012 prices. The share of spot trade in the total purchase amount accounted to approx. 20%. Prices in futures contracts can be estimated on the basis of the Japan-Australia contracts prices and prices in supplies to power plants located in Germany. On average, the prices in supplies to these power plants were higher by approximately 9% in the years 2010–2016 and prices in Australia – Japan contracts were 12% higher than CIF ARA prices in 2017. Global energy coal trade reached about 1.012 billion tonnes in 2016. In 2019, a decline by 4.8% is expected primarily due to the expected reduction in the demand in major importing countries in Asia.

In the processes of coal mining, preparation and combustion, the rejects and by-products are generated. These are, among others, the rejects from the coal washing and dry deshaling processes as well as the coal combustion by-products (fly ash and slag). Current legal and industry regulations recommend determining the content of mercury in them. The regulations also define the acceptable content of mercury. The aim of the paper was to determine the mercury content in the rejects derived from the coal cleaning processes as well as in the combustion by-products in respect of their utilization. The mercury content in the representative samples of the rejects derived from the coal washing and dry deshaling processes as well as in the coal combustion by products derived from 8 coal-fired boilers was determined. The mercury content in the rejects from the coal washing process varied from 54 to 245 μg/kg, (the average of 98 μg/kg) and in the rejects from the dry deshaling process it varied from 76 to 310 μg/kg (the average of 148 μg/kg). The mercury content in the fly ash varied from 70 to 1420 μg/kg, (the average of 567 μg/kg) and in the slag it varied from 8 to 58 μg/kg (the average of 21 μg/kg). At the moment, in light of the regulations from the point of view of mercury content in the rejects from the coal preparation processes and in the coal combustion by-products, there are no significant barriers determining the way of their utilization. Nevertheless, in the future, regulations limiting the maximum content of mercury as well as the acceptable amount of leachable mercury may be introduced. Therefore, preparing for this situation by developing other alternative methods of using the rejects and by-products is recommended.

The article presents an assessment of the value of the post-industrial landscape in the town of Rydułtowy using a comprehensive approach. It includes: 1) Defining the scope of the study taking into account regional context; 2) Inventory of mining facilities; 3) Desk study; 4) Field research and interviews; 5) Value assessment and guidelines. For assessing the value of the post-mining landscape the Architectural-Landscape Units & Interiors method was selected. The usefulness of the proposed method for the post-industrial landscape assessment was demonstrated using the case of Rydułtowy, a mining town. This article also describes the history of the mining activities in the town of Rydułtowy. The significance of the more than 200 years of mining on the growth and expansion of the town as well as its identity is reviewed. Special attention is given to the history and the present state of the most prominent element of the landscape, namely the cone-shaped landfill – Szarlota. The guidelines resulting from applying the proposed landscape value assessment are useful for a number of stakeholders and future activities planned for both the cone heaps and the mining plant.

The paper presents a brief outline of the European Union Climate and Energy Package in early 2020, as well as the EU’s plans in this respect until 2030 (Winter Package and Green Deal) and even further until 2050 (EU’s climate neutral target). Also the current condition of power generation in Poland and challenges for Polish energy sector in the nearest future are discussed. The Energy Policy of Poland until 2040 (EPP 2040) is analysed in relation to possible risks and dangers. Some improvements are proposed in regard to the implementation of the document. In addition, the current volume and perspectives of hard coal and lignite mining in Poland until 2040 are discussed and compared with an expected demand for coal in Polish power plants and combined heat and power stations. On the basis of the prognosis of energy consumption in the period 2031-2040, there seems to appear a serious risk of energy shortage due to a possible delay in a nuclear power project and lack of lignite mining at the level defined in EPP 2040 policy. Therefore, some variants of providing the security of energy supplies are taken into account and thoroughly analysed in the paper.

Sixteen samples were designed for analysis (hard coal, aggregate – barren rock, hard coal sludge). The total mercury content and the amount of mercury leaching were determined. The percentage of leachable form in the total content was calculated. The studies were carried out under various pH medium. The leachability under conditions close to neutral was determined in accordance with the PN EN 12457/1-4 standard. The leachability under acidic medium (pH of the solution – approx. 3) was determined in accordance with principles of the TCLP method. The mercury content was determined by means of the AAS method. For hard coal the total mercury content was 0.0384–0.1049 mg/kg. The level of leaching on mean was 2.6%. At the acidic medium the amount of leaching increases to an mean 4.1%. The extractive waste of aggregate type features a higher total mercury content in the finest fraction < 6 mm (up to 0.4564 mg/kg) and a lower content in the fraction 80–120 mm (up to 0.1006 mg/kg). The aggregate shows the percentage of the leachable form on mean from 1.4 to 2.2%. With pH decreasing to approx. 3, the amount of leaching grows up to mean values of 1.7–3.2%. Coal sludge features the total mercury content of 0.1368–0.2178 mg/kg. The percentage of mercury leachable form is approx. 1.8%. With pH decreasing the value increases to mean value of 3.0%. In general, the leachability of mercury from hard coals and extractive waste is low, and the leachability in an acidic medium grows approx. twice. Such factors as the type and origin of samples, their grain composition, and the pH conditions, have basic importance for the process. The time of waste seasoning and its weathering processes have the greatest impact on increasing the leaching of mercury from the extractive waste.

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.

The safety of mining operations in hard coal mines must be constantly developed and improved. There is ongoing multi-directional research focused at best recognition of the phenomenon associated with the properties of the coal-gas system and its connections with mining and geological conditions. This article presents the results of sorption experiments on coals from the Upper Silesian Coal Basin, which are characterized by varying degrees of coalification. One of the parameters that describes the kinetics of methane sorption, determining and providing valuable information about gas hazard and in particular the risk of gas and rock outbursts, is the effective diffusion coefficient De. It is derived from the solution of Fick’s second law using many simplifying assumptions. Among them is the assumption that the carbon matrix consists of only one type of pore – micropores. In fact, there are quite often at least two different mechanisms, which are connected to each other, related to the diffusion of methane from the microporous matrix and flows occurring in voids and macropores. This article presents both the unipore and bidisperse models and a set of comparisons which fit them to experimental curves for selected coals. For some samples the more complex bidisperse model gave much better results than the classic unipore one. The supremacy of the bidisperse model could be associated with the differences in the coal structure related to the coalification degree. Initial results justify further analyses on a wider set of coals using the methodology developed in this paper.

This work is a continuation and extension of previous socio-economic analyses of hard coal mines, which were conducted at the Central Mining Institute in the years 2013-2015. The paper presents the results of the economic evaluation of the hard coal mining sector in the years 2016-2018 using the Cost-Benefit Analysis (CBA) methodology. Used for the socio-economic assessment of hard coal mining, the CBA methodology enables the comprehensive evaluation of the functioning of this sector of the economy in Poland. In addition to financial aspects, which are important from the point of view of coal companies, it also included the social and environmental influence resulting from the impact of mines on the environment. Direct data of operating costs and payments (including public-law payments), incurred by the hard coal mining industry in Poland, was used. This data is obtained by Industrial Development Agency JSC, Branch Office Katowice as part of the “Program of statistical surveys of official statistics” – statistical survey “Hard coal and lignite mining industry”. They were supplemented with data coming from commonly available public statistics. For the analysed period the presented results indicate that the financial and social benefits resulting from the hard coal mining activity in Poland outweighed the financial, social and environmental costs generated by this industry. This confirms the desirability of further functioning of the hard coal mining industry in Poland, however, assuming effective restructuring activities that will result in lower costs of coal production.

Tremors occur randomly in terms of time, energy as well as the location of their focus. The present state of knowledge and technology does not allow for the precise prediction of these values. Therefore, it is extremely important to correctly select a powered roof support for specific geological and mining conditions, especially in the case of areas where dynamic phenomena are often registered. This article presents information on rock burst hazard associated with the occurrence of rock mass tremors and their influence on a powered roof support. Furthermore, protection methods of a powered roof support against the negative effects of dynamic phenomena are discussed. As a result of an analysis the methodology, to determine the impact of dynamic phenomena on the powered roof support in given geological and mining conditions is presented.

The aim of the study was to assess the possibility of using natural carbonaceous materials such aspeat, lignite, and hard coal as low-cost sorbents for the removal of Direct Orange 26 azo dye from an aqueous solution. The adsorption kinetics and the influence of experimental conditions were investigated. The following materials were used in the research: azo dye Direct Orange 26, Spill-Sorb “Fison” peat (Alberta, Canada), lignite (Bełchatów, Poland), and hard coal (“Zofiówka” mine, Poland). The morphology and porous structure of the absorbents were tested. Dye sorption was carried out under static conditions, with different doses of sorbents, pH of the solution, and ionic strength. It was observed that the adsorption of Direct Orange 26 dye on all three adsorbents was strongly dependent on the pH of the solution, while the ionic strength of the solution did not affect the adsorption efficiency. The adsorption kinetics were consistent with the pseudo-second-order reaction model. The stage which determines the rate of adsorption is the diffusion of the dye in the near-surface layer. The process of equilibrium adsorption of Direct Orange 26 dye on all tested adsorbents is best described by the Langmuir isotherm. The maximum adsorption capacity for peat, brown coal and hard coal was 17.7, 15.1 and 13.8 mg/g, respectively. The results indicate that peat, lignite, and hard coal can be considered as alternative adsorbents for removing azo dyes from aqueous solutions.

The paper presents investigations of dust fractional composition concerning combustion of hard coal in circulating fluidized bed boilers (CFBs). Experimentally determined emission factors for such boilers, and also typical pulverized-fuel furnaces, furnaces with mechanical stoker and domestic furnaces arc presented. They all have been obtained for Upper Silcsian type of coal. Total dust and characteristic fractions: PM2.5 and PM 10 are covered.

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.