scholarly journals Analysis of Exploitation Parameters in Drainage Boreholes of the Longwall Demethylation System. Case Study

2021 ◽  
Vol 4 (1) ◽  
pp. 23-39
Author(s):  
Henryk Badura ◽  
Zygmunt Łukaszczyk
Keyword(s):  
Methane Concentration ◽  
Coal Mines ◽  
Extraction Process ◽  
Longwall Face ◽  
Coal Bed ◽  
Hard Coal ◽  
Methane Mixture ◽  
Roof Rocks ◽  
Made In

Abstract In hard coal mines with methane, there is often a need to apply demethylation in order to keep the methane concentration not exceeding 2% in the ventilation air. The basic demethylation method in longwall areas is through drainage boreholes made in the roof rocks of the coal bed, from top gate, in front of the longwall. The drainage boreholes are usually made in bundles, in a fan-shaped arrangement, with several boreholes in each bundle. The paper presents the results of measurements and tests of the efficiency of a bundle of four drainage boreholes drilled approximately 100 m in front of the longwall face. The efficiency of individual boreholes was analyzed in time and depending on the distance of borehole outlets from the longwall face. It was found that there is a large variation in the extraction of air-methane mixture by individual drainage boreholes, as well as large differences in the efficiency of individual drainage boreholes during the longwall extraction process.

The Use of Fuzzy Systems in the Designing of Mining Process in Hard Coal Mines

2014 ◽  
Vol 59 (3) ◽  
pp. 741-760
Author(s):  
Edyta Brzychczy ◽  
Marek Kęsek ◽  
Aneta Napieraj ◽  
Marta Sukiennik
Keyword(s):  
Knowledge Base ◽  
Fuzzy Systems ◽  
Coal Mines ◽  
Fuzzy Rules ◽  
Longwall Face ◽  
Hard Coal ◽  
Site Conditions ◽  
The Given ◽  
Selection Of

Abstract This article presents examples of solutions supporting the design of certain elements of the mining process in coal mines. The focus is on two fuzzy systems: the first supports the selection of equipment for longwall faces (FSES); and the second supports the estimation of production results (FSOE). System FSES generates proposals for equipment in designed longwall faces. The module of fuzzing in this system enables a fuzzing operation for the following quantitative variables: longwall length; longwall height; longitudinal and crosswise incline of the longwall, workability of the coal and thickness of rock vein in a given section of the longwall. The knowledge base includes over 100 fuzzy rules indicating possible options for equipment under specified site conditions. After a proposal of equipment is generated, it is then possible to insert the values obtained into the second system FSOE, which estimates output for a given shift time using the chosen parameters. The module of fuzzing in system FSOE includes 9 variables, which are crucial in determining shift output for the given longwall face. The knowledge base in this system contains over 2000 rules. As a result of the operation of both systems, the designer receives both a proposal of equipment for the designed longwall face and the size of shift output under the given conditions. Operation of the two systems has been presented using a case study.

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 the similarity of hard coal mines in terms of the number of dangerous incidents caused by the activation of natural hazards

2019 ◽  
Vol 2 (1) ◽  
pp. 91-100
Author(s):  
Magdalena Tutak
Keyword(s):  
Rock Burst ◽  
Natural Hazards ◽  
Coal Dust ◽  
Coal Mines ◽  
Hard Coal ◽  
Dust Explosion ◽  
Coal Basin ◽  
Taxonomic Analysis ◽  
Upper Silesian Coal Basin ◽  
Roof Rocks

Abstract Hard coal mines and mining enterprises involved in hard coal exploitation in the area of the Upper Silesian Coal Basin (Górnośląskie Zagłębie Węglowe) are characterised by the presence of natural hazards typical of this type of exploitation. These hazards include the risks related to methane, coal dust explosion, endogenous fires, as well as rock burst and caving of roof rocks. The article presents the results of a taxonomic analysis aimed at determining the similarity of hard coal mines and mining enterprises in Poland in terms of the dangerous incidents caused by the risks related to methane, coal dust explosion, endogenous fires, as well as rock burst and caving of roof rocks. The analysis was carried out for the 2008-2018 data and encompassed a total of 26 hard coal mines and mining enterprises located in the Upper Silesian Coal Basin. The analysis was performed using the k-means method of non-hierarchical clustering. The main objective of the article was to determine homogenous groups (clusters) of mines exhibiting the greatest similarity in terms of dangerous incidents caused by the activation of natural hazards in the years 2008-2018. These data can be successfully used for the development of preventive measures and risk analyses for these enterprises.

Virtual Analysis of the Mining Support under Loads of the Roof

2013 ◽  
Vol 837 ◽  
pp. 393-398 ◽  
Author(s):  
Aleksander Gwiazda
Keyword(s):  
Coal Mining ◽  
Coal Mines ◽  
Work Conditions ◽  
Coal Bed ◽  
Virtual Model ◽  
Virtual Analysis ◽  
The Stability ◽  
Roof Rocks ◽  
Investigation Process ◽  
Roof Support

The paper presents the results of virtual analysis of the stability of mining roof supports loaded by the roof rocks. The hydraulic roof support generally accounts for over 50% of the total value of a coal mining and excavating system. Many reports show that in some conditions roof supports behave differently than foreseen. To explain this phenomena the investigations basing on the virtual model were done [1,2]. This phenomena is very dangerous for miners because this behaviour of a mining roof support may cause dangerous accidents in coal mines. In the investigation process some questions have been asked. Firstly what type of a mining support is more liable to this behaviour. Secondly what work conditions are the most dangerous. To analyse this phenomena it was used models of two types of a mining support. One with two props and one with four ones. Results show that that the problem of plunged of roof parts of a support in the coal bed is consider with the construction of the support. The most dangerous is the roof support with two props. The consequences of this results are the recommendations to use rather supports with four props then two.

A framework for learning and embedding multi-sensor forecasting models into a decision support system: A case study of methane concentration in coal mines

2018 ◽  
Vol 451-452 ◽  
pp. 112-133 ◽  
Author(s):  
Dominik Ślęzak ◽  
Marek Grzegorowski ◽  
Andrzej Janusz ◽  
Michał Kozielski ◽  
Sinh Hoa Nguyen ◽  
...  
Keyword(s):  
Decision Support ◽  
Decision Support System ◽  
Support System ◽  
Methane Concentration ◽  
Coal Mines ◽  
Forecasting Models ◽  
System A

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 Computer Systems Supporting the Management of Machines/Equipment in Hard Coal Mines. Case Study

2019 ◽  
Vol 27 (3) ◽  
pp. 138-143
Author(s):  
Witold Biały ◽  
Jiri Fries
Keyword(s):  
Computer Systems ◽  
Coal Mines ◽  
Spare Parts ◽  
Economic Effects ◽  
Production Costs ◽  
Hard Coal ◽  
Operation And Maintenance ◽  
High Production ◽  
Effective Use

AbstractComputer systems supporting the management of machines operation and maintenance in companies have been successfully applied in many branches of industry. Over the last few years these systems have been considerably transformed. It also seems that using them for operating mining machines in hard coal mines is inevitable, as maintenance generates high production costs. If implemented, the systems will allow for optimization of stocks, spare parts and materials, supplies, outsourced services as well as maintenance-repair works. Application of a system supporting the management of mining machines/equipment will also enable a better, more effective use of employees. As a result of these actions, the time needed for preparations and repair will be shortened, which will translate directly into the economic effects of mines.

Biorefinery implementation for recovery debottlenecking at existing pulp mills- Part II: Techno-economic evaluation

TAPPI Journal ◽  
2012 ◽  
Vol 11 (8) ◽  
pp. 17-24 ◽  
Author(s):  
HAKIM GHEZZAZ ◽  
LUC PELLETIER ◽  
PAUL R. STUART
Keyword(s):  
Cost Estimation ◽  
Process Model ◽  
Black Liquor ◽  
Pulp Mill ◽  
Value Added ◽  
Economic Assessment ◽  
Extraction Process ◽  
Estimation Methods ◽  
Precipitation Process

The evaluation and process risk assessment of (a) lignin precipitation from black liquor, and (b) the near-neutral hemicellulose pre-extraction for recovery boiler debottlenecking in an existing pulp mill is presented in Part I of this paper, which was published in the July 2012 issue of TAPPI Journal. In Part II, the economic assessment of the two biorefinery process options is presented and interpreted. A mill process model was developed using WinGEMS software and used for calculating the mass and energy balances. Investment costs, operating costs, and profitability of the two biorefinery options have been calculated using standard cost estimation methods. The results show that the two biorefinery options are profitable for the case study mill and effective at process debottlenecking. The after-tax internal rate of return (IRR) of the lignin precipitation process option was estimated to be 95%, while that of the hemicellulose pre-extraction process option was 28%. Sensitivity analysis showed that the after tax-IRR of the lignin precipitation process remains higher than that of the hemicellulose pre-extraction process option, for all changes in the selected sensitivity parameters. If we consider the after-tax IRR, as well as capital cost, as selection criteria, the results show that for the case study mill, the lignin precipitation process is more promising than the near-neutral hemicellulose pre-extraction process. However, the comparison between the two biorefinery options should include long-term evaluation criteria. The potential of high value-added products that could be produced from lignin in the case of the lignin precipitation process, or from ethanol and acetic acid in the case of the hemicellulose pre-extraction process, should also be considered in the selection of the most promising process option.

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