scholarly journals Forecasting Methane Emissions from Hard Coal Mines Including the Methane Drainage Process

Energies ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3840 ◽  
Author(s):  
Magdalena Tutak ◽  
Jarosław Brodny
Keyword(s):  
Neural Networks ◽  
Greenhouse Gas ◽  
Natural Environment ◽  
Underground Mining ◽  
Coal Mines ◽  
Energy Resource ◽  
High Energy ◽  
Methane Emissions ◽  
Hard Coal ◽  
Methane Drainage

With regard to underground mining, methane is a gas that, on the one hand, poses a threat to the exploitation process and, on the other hand, creates an opportunity for economic development. As a result of coal exploitation, large amounts of coal enter the natural environment mainly through ventilation systems. Since methane is a greenhouse gas, its emission has a significant impact on global warming. Nevertheless, methane is also a high-energy gas that can be utilized as a very valuable energy resource. These different properties of methane prompted an analysis of both the current and the future states of methane emissions from coal seams, taking into account the possibilities of its use. For this reason, the following article presents the results of the study of methane emissions from Polish hard coal mines between 1993–2018 and their forecast until 2025. In order to predict methane emissions, research methodology was developed based on artificial neural networks and selected statistical methods. The multi-layer perceptron (MLP) network was used to make a prognostic model. The aim of the study was to develop a method to predict methane emissions and determine trends in terms of the amount of methane that may enter the natural environment in the coming years and the amount that can be used as a result of the methane drainage process. The methodology developed with the use of neural networks, the conducted research, and the findings constitute a new approach in the scope of both analysis and prediction of methane emissions from hard coal mines. The results obtained confirm that this methodology works well in mining practice and can also be successfully used in other industries to forecast greenhouse gas and other substance emissions.

scholarly journals Tests to Ensure the Minimum Methane Concentration for Gas Engines to Limit Atmospheric Emissions

2019 ◽  
Author(s):  
Marek Borowski ◽  
Piotr Życzkowski ◽  
Rafał Łuczak ◽  
Michał Karch ◽  
Jianwei Cheng
Keyword(s):  
Carbon Dioxide ◽  
Greenhouse Gas ◽  
Methane Concentration ◽  
Coal Mines ◽  
Drainage System ◽  
Hard Coal ◽  
Atmospheric Emissions ◽  
Coal Seams ◽  
Mining Operations ◽  
Methane Drainage

During the extraction of hard coal in Polish conditions, methane is emitted, which is referred to as mine gas. As a result of the desorption of methane, a greenhouse gas is released from coal seams. In order to reduce atmospheric emissions, methane from coal seams is captured by a methane drainage system. On the other hand, methane, which has been separated into underground mining excavations, is discharged into the atmosphere with a stream of ventilation air. For many years, Polish hard coal mines have been capturing methane to ensure the safety of the crew and the continuity of mining operations. As a greenhouse gas, methane has a significant potential, as it is more effective at absorbing and re-emitting radiation than carbon dioxide. The increase in the amount of methane in the atmosphere is a significant factor influencing global warming, however, it is not as strong as the increase in carbon dioxide. Therefore, in Polish mines, the methane-air mixture captured in the methane drainage system is not emitted to the atmosphere, but burned as fuel in systems, including cogeneration systems, to generate electricity, heat and cold. However, in order for such use to be possible, the methane-air mixture must meet appropriate quality and quantity requirements. The article presents an analysis of changes in selected parameters of the captured methane-air mixture from one of the hard coal mines in the Upper Silesian Coal Basin in Poland. The paper analyses the changes in concentration and size of the captured methane stream through the methane capturing system. The gas captured by the methane drainage system, as an energy source, can be used in cogeneration, when the methane concentration is greater than 40%. Considering the variability of CH4 concentration in the captured mixture, it was also indicated which pure methane stream must be added to the gas mixture in order for this gas to be used as a fuel for gas engines. The balance of power of produced electric energy in gas engines is presented. Possible solutions ensuring constant concentration of the captured methane-air mixture are also presented.

scholarly journals Tests to Ensure the Minimum Methane Concentration for Gas Engines to Limit Atmospheric Emissions

Energies ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 44 ◽  
Author(s):  
Marek Borowski ◽  
Piotr Życzkowski ◽  
Rafał Łuczak ◽  
Michał Karch ◽  
Jianwei Cheng
Keyword(s):  
Carbon Dioxide ◽  
Greenhouse Gas ◽  
Methane Concentration ◽  
Coal Mines ◽  
Drainage System ◽  
Hard Coal ◽  
Atmospheric Emissions ◽  
Coal Seams ◽  
Mining Operations ◽  
Methane Drainage

During the extraction of hard coal in Polish conditions, methane is emitted, which is referred to as ‘mine gas’. As a result of the desorption of methane, a greenhouse gas is released from coal seams. In order to reduce atmospheric emissions, methane from coal seams is captured by a methane drainage system. On the other hand, methane, which has been separated into underground mining excavations, is discharged into the atmosphere with a stream of ventilation air. For many years, Polish hard coal mines have been capturing methane to ensure the safety of the crew and the continuity of mining operations. As a greenhouse gas, methane has a significant potential, as it is more effective at absorbing and re-emitting radiation than carbon dioxide. The increase in the amount of methane in the atmosphere is a significant factor influencing global warming, however, it is not as strong as the increase in carbon dioxide. Therefore, in Polish mines, the methane–air mixture captured in the methane drainage system is not emitted to the atmosphere, but burned as fuel in systems, including cogeneration systems, to generate electricity, heat and cold. However, in order for such use to be possible, the methane–air mixture must meet appropriate quality and quantity requirements. The article presents an analysis of changes in selected parameters of the captured methane–air mixture from one of the hard coal mines in the Upper Silesian Coal Basin in Poland. The paper analyses the changes in concentration and size of the captured methane stream through the methane capturing system. The gas captured by the methane drainage system, as an energy source, can be used in cogeneration, when the methane concentration is greater than 40%. Considering the variability of CH4 concentration in the captured mixture, it was also indicated which pure methane stream must be added to the gas mixture in order for this gas to be used as a fuel for gas engines. The balance of power of produced electric energy in gas engines is presented. Possible solutions ensuring constant concentration of the captured methane–air mixture are also presented.

scholarly journals The Impact of the Coexistence of Methane Hazard and Rock-Bursts on the Safety of Works in Underground Hard Coal Mines

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 128
Author(s):  
Justyna Swolkień ◽  
Nikodem Szlązak
Keyword(s):  
Rock Burst ◽  
Methane Concentration ◽  
High Energy ◽  
Hard Coal ◽  
Coal Seams ◽  
Safety Level ◽  
Methane Drainage ◽  
Innovative Methods ◽  
Hard Coal Mining ◽  
The Impact

Several natural threats characterize hard coal mining in Poland. The coexistence of methane and rock-burst hazards lowers the safety level during exploration. The most dangerous are high-energy bumps, which might cause rock-burst. Additionally, created during exploitation, safety pillars, which protect openings, might be the reason for the formation of so-called gas traps. In this part, rock mass is usually not disturbed and methane in seams that form the safety pillars is not dangerous as long as they remain intact. Nevertheless, during a rock-burst, a sudden methane outflow can occur. Preventing the existing hazards increases mining costs, and employing inadequate measures threatens the employees’ lives and limbs. Using two longwalls as examples, the authors discuss the consequences of the two natural hazards’ coexistence. In the area of longwall H-4 in seam 409/4, a rock-burst caused a release of approximately 545,000 cubic meters of methane into the excavations, which tripled methane concentration compared to the values from the period preceding the burst. In the second longwall (IV in seam 703/1), a bump was followed by a rock-burst, which reduced the amount of air flowing through the excavation by 30 percent compared to the airflow before, and methane release rose by 60 percent. The analyses presented in this article justify that research is needed to create and implement innovative methods of methane drainage from coal seams to capture methane more effectively at the stage of mining.

scholarly journals Analysis of the Scale of Methane Hazard in Polish Hard Coal Mines

2018 ◽  
Vol 1 (1) ◽  
pp. 801-807 ◽  
Author(s):  
Magdalena Tutak
Keyword(s):  
Bearing Capacity ◽  
Natural Environment ◽  
Preventive Measures ◽  
Coal Mines ◽  
Mining Industry ◽  
Vital Role ◽  
Hard Coal ◽  
Explosive Mixture ◽  
Methane Extraction ◽  
Methane Mixture

Abstract In the majority of Polish mines, the exploitation of hard coal is accompanied by the release of considerable amounts of methane. Being flammable and explosive, methane may form an explosive mixture with air once it appears in mine workings. For this reason, the methane hazard is recognised as one of the ventilation risks in the mining industry. This process leads to the formation of air and methane mixture, whose considerable amounts permeate into the atmosphere and the natural environment. This phenomenon is extremely unfavourable because methane is, besides carbon dioxide, yet another gas that exacerbates the greenhouse effect. For this reason, it is increasingly more common to equip mines with methane collection systems in the process of demethylation. These play a vital role for both the natural environment and the safety of work in mines. A reduction of the methane content in headings increases the safety of the working crew and enhances the effectiveness of mining production. The article presents an analysis of the methane-related hazard based on methane emissions during mining exploitation. The analysis was based on the data concerning the amount of methane emitted into the atmosphere and collected by methane extraction systems from 16 coal mines. It led to identification of homogenous mines with similar values of the absolute methane-bearing capacity and ventilation methane-bearing capacity as well as with similar amounts of methane collected by methane extraction systems. The analysis was performed using the non-hierarchical k-average method, which belongs to the group of algorithms for analysing clusters. As a result, the mines were divided into the assumed number of groups. The results obtained made it possible to determine a group of mines in which, in the Author’s opinion, similar systems can be applied for controlling and reducing the methane hazard. These results also open up numerous possibilities for undertaking joint business ventures by the mines in terms of using the collected methane and implementing preventive measures.

scholarly journals Analysis of methane hazard in longwall working equipped with a powered longwall complex

2020 ◽  
Vol 174 ◽  
pp. 01011
Author(s):  
Leszek Sobik ◽  
Jarosław Brodny ◽  
Gennady Buyаlich ◽  
Pavel Strelnikov
Keyword(s):  
High Performance ◽  
Underground Mining ◽  
Practical Knowledge ◽  
Mining Operation ◽  
Mining Area ◽  
Hard Coal ◽  
Coal Seams ◽  
Methane Drainage ◽  
High Degree ◽  
Advanced Model

Most of currently exploited hard coal seams has a very high degree of methane saturation. Consequently, the mining process of such deposits generates substantial amounts of methane. This in turn increases the risk of fire and/or explosion of this gas. Methane hazard is currently one of the most dangerous threats occurring in the process of underground mining exploitation. In particular, this applies to longwall excavations where the rock mass mining process generates the highest level of this gas. Commonly used high-performance longwall complexes cause an increase in the amount of coal output, which also causes an increase in the amount of methane released. In order to prevent hazardous concentrations, appropriate ventilation systems and atmosphere monitoring in mining excavations are used. The paper discusses currently used methods designed to limit risks caused by methane such as methane drainage. The paper presents an example of the use of an innovative method of analysing methane risk status and measures aimed at minimizing it. The developed method is based on air parameters in the actual mining area which were then used to create a method of ventilation for such excavations. The method combines advanced model analysis and experience of mine employees and integrates academic and practical knowledge. The main objective of the activities presented in the article was to improve the safety of mining operation

scholarly journals Comparison of Methane Control Methods in Polish and Vietnamese Coal Mines

2018 ◽  
Vol 35 ◽  
pp. 01004
Author(s):  
Marek Borowski ◽  
Zbigniew Kuczera
Keyword(s):  
Coal Mining ◽  
Coal Dust ◽  
Coal Mines ◽  
Hard Coal ◽  
Control Methods ◽  
Prevention Measures ◽  
Methane Drainage ◽  
Hazard Control ◽  
Preventive Actions ◽  
Coal Deposits

Methane hazard often occurs in hard coal mines and causes very serious accidents and can be the reason of methane or methane and coal dust explosions. History of coal mining shows that methane released from the rock mass to the longwall area was responsible for numerous mining disasters. The main source of methane are coal deposits because it is autochthonous gas and is closely related with carbonification and forming of coal deposits. Degree of methane saturation in coal deposits depends on numerous factors; mainly on presence or lack of insulating layers in cover deposit that allow or do not on degasification and easily methane outflow into surroundings. Hence in coal mining there are coal deposits that contain only low degree of methane saturation in places where is lack of insulating layers till high in methane coal deposits occurring in insulating claystones or in shales. Conducting mining works in coal deposits of high methane hazard without using of special measures to combat (ventilation, methane drainage) could be impossible. Control of methane hazard depends also on other co-occuring natural dangers for which used preventive actions eliminate methane hazard. Safety in mines excavating coal deposits saturated with methane depends on the correct estimation of methane hazard, drawn up forecasts, conducted observations, hazard control as well as undertaken prevention measures. Methane risk prevention includes identification and control methods of methane hazards as well as means of combating the explosive accumulation of methane in longwall workings. The main preventive actions in underground coal mines are: effective ventilation that prevents forming of methane fuses or placed methane accumulation in headings ventilated by airflow created by main fans and in headings with auxiliary ventilation, methane drainage using drain holes that are drilled from underground headings or from the surface, methanometry control of methane concentration in the air; location of the sensors is defined by law, additional ventilation equipment used in places of lower intensity of ventilation and places where methane is concentrated.

scholarly journals Enhancement of the Walbrzych Hard Coal Mines Geographic Information System for its application in studies of mining deformations

2018 ◽  
Vol 55 ◽  
pp. 00002 ◽  
Author(s):  
Jan Blachowski ◽  
Paulina Herkt
Keyword(s):  
Information System ◽  
Surface Deformation ◽  
Underground Mining ◽  
Coal Mines ◽  
Geographic Information ◽  
Hard Coal ◽  
Mining Sites ◽  
Mining Areas ◽  
Geospatial Analyses ◽  
Interactive Map

Geographic information systems (GIS) have been increasingly used in augmenting studies of mining and post-mining areas such as surface deformation analyses, risk assessment associated with old mining sites, identification of old mining sites and other. Up-to-date and complete geodatabase is an indispensable element of any geoinformation system facilitating such geospatial analyses. In this paper the process of verification and integration of Walbrzych Hard Coal Mines geodatabase and project of enhancing the Deformation Information System for these mines with web map application of underground workings and query tools developed with free and open source software (FOSS) have been described. The interactive map allows users to interact and obtain precise information on location and characteristics of underground mining and the query tools streamline pre-processing operations necessary for geospatial analyses.

scholarly journals Possibilities of Capturing Methane from Hard Coal Deposits Lying at Great Depths

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3542
Author(s):  
Nikodem Szlązak ◽  
Justyna Swolkień
Keyword(s):  
Underground Mining ◽  
Drainage System ◽  
Hard Coal ◽  
Coal Seams ◽  
Second Stage ◽  
Methane Drainage ◽  
Coal Deposits ◽  
Significant Difference ◽  
Flammable Gas ◽  
Deposition Depth

Methane present in coal seams is a natural hazard present during the exploitation of underground mining plants. It is an explosive and flammable gas that is released into mining excavations, and it is necessary to reduce its concentration. Capturing methane while preparing extraction is virtually impossible due to the low permeability of coal resulting from its deposition depth. After the beginning of exploitation and disrupting the seam’s structure, methane is released into mine air. The most common method of minimizing gas released into ventilation air is draining the rock mass. This method allows achieving the desired ventilation parameters but requires appropriate mining techniques in hazardous areas. The article presents the example of methane capture during the operation in the longwall B-15 with an overlying drainage gallery. The authors have highlighted an example of the longwall B-15 that when using this particular drainage method, allowed capturing twice the amount of methane forecasted, thus increasing the efficiency of methane drainage. At the preliminary stage of longwall development, the amount of methane charged by the drainage system had relatively low values, reaching 15 m3/min. In the next few months, these parameters increased and varied between 35 to 55 m3/min. A significant difference in methane capture appeared in the second stage of exploitation, where the highest value of captured methane reached 82 m3/min. This particular longwall example shows that it is crucial to properly design the drainage system for seams with high forecasted methane release. It is worth remembering that using a drainage gallery provides an increase in the methane capture from the desorption zone areas, thus increasing total methane capture in comparison to forecasts.

scholarly journals The Combustion of Methane from Hard Coal Seams in Gas Engines as a Technology Leading to Reducing Greenhouse Gas Emissions—Electricity Prediction Using ANN

Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4429
Author(s):  
Marek Borowski ◽  
Piotr Życzkowski ◽  
Jianwei Cheng ◽  
Rafał Łuczak ◽  
Klaudia Zwolińska
Keyword(s):  
Coal Seam ◽  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Coal Mine ◽  
Electricity Production ◽  
Hard Coal ◽  
Neural Network Models ◽  
Gas Emissions ◽  
Methane Drainage ◽  
Geological Conditions

Greenhouse gases such as carbon dioxide and methane cause global warming and consequently climate change. Great efforts are being made to reduce greenhouse gas emissions with the objective of addressing this problem, hence the popularity of technologies conductive to reducing greenhouse gas emissions. CO2 emissions can be reduced by improving the thermal efficiency of combustion engines, for example, by using cogeneration systems. Coal mine methane (CMM) emerges due to mining activities as methane released from the coal and surrounding rock strata. The amount of methane produced is primarily influenced by the productivity of the coal mine and the gassiness of the coal seam. The gassiness of the formation around the coal seam and geological conditions are also important. Methane can be extracted to the surface using methane drainage installations and along with ventilation air. The large amounts of methane captured by methane drainage installations can be used for energy production. This article presents a quarterly summary of the hourly values of methane capture, its concentration in the methane–air mixture, and electricity production in the cogeneration system for electricity and heat production. On this basis, neural network models have been proposed in order to predict electricity production based on known values of methane capture, its concentration, pressure, and parameters determining the time and day of the week. A prediction model has been established on the basis of a multilayer perceptron network (MLP).

scholarly journals Exposure to Harmful Dusts on Fully Powered Longwall Coal Mines in Poland

2018 ◽  
Vol 15 (9) ◽  
pp. 1846 ◽  
Author(s):  
Jarosław Brodny ◽  
Magdalena Tutak
Keyword(s):  
Underground Mining ◽  
Coal Dust ◽  
Coal Mines ◽  
Chronic Respiratory Disease ◽  
Working Environment ◽  
Hard Coal ◽  
Free Silica ◽  
Stone Dust ◽  
Hard Coal Mining

The mining production process is exposed to a series of different hazards. One of them is the accumulation of dust which can pose a serious threat to the life and health of mine workers. The analysis of dust hazard in hard coal mining should include two aspects. One is the risk of coal dust explosions, which poses a direct risk of injury or even loss of life, the second is the risk of harmful dust, associated with the possibility of negative health effects as a result of long-term exposure to dust in the worker’s body. The technologies currently applied in underground mining produce large amounts of coal and stone dust. Long-term exposure to dust and crystalline silica may cause chronic respiratory disease. The article presents the results of tests on the dust levels in the area of a fully-powered longwall. The tests were conducted for five longwalls from different hard coal mines. In each of them, the average values of inhalable and respirable dust as well as the percentage content of free silica in the dust were determined in ten selected working positions. Additionally, for the longwall with the highest dust concentration, the levels of dust were determined for the basic activities related to the phases of the technological cycle. The comparative analysis conducted and the results obtained demonstrate large variations in the dust levels in the different areas. The permissible values were significantly exceeded in a number of cases. This poses a great threat to the health of Polish miners. The results obtained indicate that it is necessary to undertake more effective measures in order to improve the working environment of the crew in hard coal mines.

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