The Determination of the Methane Content of Coal Seams Based on Drill Cutting and Core Samples from Coal Mine Roadway

The determination of methane content of coal seams is conducted in hard coal mines in order to assess the state of methane hazard but also to evaluate gas resources in the deposit. In the world’s mining industry, natural gas content in coal determination is usually based on direct methods. It remains the basic method in Poland as well. An important element in the determination procedure is the gas loss that occurs while collecting a sample for testing in underground conditions. In the method developed by the authors, which is a Polish standard, based on taking a sample in the form of drill cuttings, this loss was established at a level of 12%. Among researchers dealing with the methane content of coal, there are doubts related to the procedures adopted for coal sampling and the time which passes from taking a sample to enclosing it in a sealed container. Therefore, the studies were designed to evaluate the degree of degassing of the sample taken in the form of drill cuttings according to the standard procedure and in the form of the drill core from a coal mine roadway. The results show that the determinations made for the core coincide with the determinations made for the drill cutting samples, with the loss of gas taken into account.

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Estimation of Gas Loss in Methodology for Determining Methane Content of Coal Seams

Energies ◽

10.3390/en14040982 ◽

2021 ◽

Vol 14 (4) ◽

pp. 982

Author(s):

Nikodem Szlązak ◽

Dariusz Obracaj ◽

Marek Korzec

Keyword(s):

Coal Seam ◽

Coal Sample ◽

Uniform Method ◽

Methane Content ◽

Gas Content ◽

National Standard ◽

Desorption Rate ◽

Coal Seams ◽

Gas Loss

The determination of natural gas content in coal seams is essential to safe mining activities and to estimate gas resources. It is used to estimate methane emissions into workings, which is very important when using preventive measures of methane ignition and explosion. Methane content in a coal seam is mostly determined using a direct method. However, a problem with estimation of gas loss during collecting a sample in a mine occurs in each method. That gas loss is estimated using different procedures. In the Polish mining industry, methane content in a coal seam is mostly determined during roadway advancing faces in coal seams. The differences in procedures for determining methane content in coal in various laboratories gave rise to starting research into developing a new method. This article presents results of study of gas loss unification for the determination of methane content in coal seams. The research focused mainly on determining a uniform method for estimating gas loss using the early adsorption diffusion process. The method of coal sample saturation with methane was used to measure gas desorption rate. Saturation pressures of samples were determined for coal seams in the Upper-Silesian Coal Basin. The analysis of desorption results allowed to determine the dependence between methane content in a coal sample and the initial methane content in a coal seam. It was concluded that the desorption rate was highest within two minutes. For the procedure of coal sampling, gas loss was determined at 12% of both desorbed and residual gases. The presented research results gave rise to developing a uniform method for determining gas content used in Polish coal mining. The method was accepted as the national standard. Methodology using a new gas loss estimation procedure allows for achieving relatively fast results of the determination of methane content in coal seams, which is very important, especially in gassy mines.

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Analysis of the Natural Methane Content of Boldyrevsky Seam at S.M. Kirov Mine of JSC SUEK-Kuzbass

Occupational Safety in Industry ◽

10.24000/0409-2961-2021-3-61-66 ◽

2021 ◽

pp. 61-66

Author(s):

E.V. Fedorov ◽

◽

S.B. Kulibaba ◽

A.A. Meshkov ◽

◽

...

Keyword(s):

Methane Content ◽

Actual Data ◽

Gas Content ◽

Coal Seams ◽

Actual Distribution ◽

Coal Gas ◽

Residual Gas ◽

Mine Workings ◽

Host Rocks

S.M. Kirov mine of JSC SUEK-Kuzbass develops Boldyrevsky and Polenovsky seams and is classified as a super-category for methane. Under these conditions, the development of seams requires a set of measures for their degassing. Methods and parameters for degassing the main sources of methane release in the coal mines are selected considering the faces gas content. It is calculated based on the natural methane content of the coal seams and host rocks determined at the stage of geologic exploration activity. The aim of the work conducted by the authors is to establish the actual distribution of natural methane seam Boldyrevsky based on the analysis of research results of the coal-gas samples and experimental evaluation of the residual gas content in the mine workings. Natural gas content of the mine field of S.M. Kirov JSC SUEK-Kuzbass mine was determined based on the analysis of 538 coal-gas samples on 30 seams. All the coal and gas samples taken from Boldyrevsky seam were analyzed. Distribution of the actual values of natural methane content from the hypsometric depths of the seam was plotted. Distribution was plotted concerning the actual values of natural methane from hypsometric depths of the formation. The obtained data were compared with the results of experimental determination of the residual gas content of Boldyrevsky seam from the mine workings. Based on the results obtained, CH4 isogases were constructed based on the actual and maximum values of the natural methane content in Boldyrevsky seam. It is established that the natural methane content of Boldyrevsky seam, that was determined at the stage of geological exploration for the entire field of S.V. Kirov mine, has overestimated values — by 35–40 % compared to the actual data, and by 25–30% in relation to the maximum actual data.

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Methane Content Estimation in DuongHuy Coal Mine

E3S Web of Conferences ◽

10.1051/e3sconf/20183501005 ◽

2018 ◽

Vol 35 ◽

pp. 01005 ◽

Cited By ~ 1

Author(s):

Van Thinh Nguyen ◽

Waldemar Mijał ◽

Vu Chi Dang ◽

Thi Tuyet Mai Nguyen

Keyword(s):

Experimental Data ◽

Coal Mining ◽

Coal Mine ◽

Coal Mines ◽

Methane Content ◽

Underground Coal Mining ◽

Coal Seams ◽

Underground Coal Mine ◽

Different Depths ◽

Quang Ninh

Methane hazard has always been considered for underground coal mining as it can lead to methane explosion. In Quang Ninh province, several coal mines such as Mạo Khe coal mine, Khe Cham coal mine, especially Duong Huy mine that have high methane content. Experimental data to examine contents of methane bearing coal seams at different depths are not similar in Duong coal mine. In order to ensure safety, this report has been undertaken to determine a pattern of changing methane contents of coal seams at different exploitation depths in Duong Huy underground coal mine.

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Methane emissions against the background of natural and mining conditions in the Budryk and Pniówek mines in the Upper Silesian Coal Basin (Poland)

Environmental Earth Sciences ◽

10.1007/s12665-021-10063-4 ◽

2021 ◽

Vol 80 (22) ◽

Author(s):

Marcin Dreger ◽

Sławomir Kędzior

Keyword(s):

Methane Emissions ◽

Geological Structure ◽

Methane Content ◽

Coal Extraction ◽

Hard Coal ◽

Coal Seams ◽

Coal Basin ◽

Related Factors ◽

Upper Silesian Coal Basin ◽

Mining Conditions

AbstractThe paper presents the variability of hard coal output, methane content and methane emissions into coal workings and into the atmosphere from the two most methane-gassy coal mines in Poland. The Budryk mine is one of the youngest mines in Poland, but it is the most methane-gassy as well. In 2016, the total CH4 emissions exceed 140 million of m3. This large increase in methane emissions to mine workings is primarily related to the increase in the depth of coal extraction (up to 1290 m) and, consequently, the rapid increase in the methane content in coal seams (up to 10–12 m3/Mg coaldaf). On the other hand, in the Pniówek mine, methane emission was the highest at the beginning of the study period (1986–1991). During the following years, emission decreased to the values of less than 140 million of m3, which were still one of the largest amounts of emitted methane in the entire Upper Silesian Coal Basin. The coexistence of natural factors, such as the geological structure and gas distribution, as well as mining-related factors, i.e. the depth of mining, the intensity of coal extraction determines the temporal variability of methane emissions in the studied mines.

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CBM Resources Estimations for the Development of Coal Mine Methane in the Asturian Central Basin, Spain

Proceedings ◽

10.3390/proceedings2231404 ◽

2018 ◽

Vol 2 (23) ◽

pp. 1404

Author(s):

Pablo Cienfuegos-Suárez ◽

Efrén García-Ordiales ◽

Diego Alonso-Fernández ◽

Jorge Enrique Soto-Yen

Keyword(s):

Coal Mine ◽

Coalbed Methane ◽

Technological Development ◽

Gas Content ◽

Central Basin ◽

Economic Interest ◽

Coal Seams ◽

Coal Basin ◽

Coal Mine Methane ◽

Made In

New technological development and a best knowledge of the basin allow to have justified expectation to find coalbed methane reserves. Measurements of gas content in unexploited coal seams are made in order to estimate the CBM could revive the economic interest of the Asturian Central Coal Basin (ACCB). According to first estimations based on the studies accomplished, the minimum resources of coalbed methane in the whole of the Asturian Central Coal Basin are in the order of 25,000 Mm3 and the gas content of the coal seams range from 6 m3 to 14 m3/t. The introduction should briefly place the study in a broad context and define the purpose of the work and its significance.

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A Study of the Laws of Abnormal Gas Emissions and the Stability Controls for Coal Mine Walls in Deeply Buried High-Gas Coal Seams

Advances in Civil Engineering ◽

10.1155/2020/8894854 ◽

2020 ◽

Vol 2020 ◽

pp. 1-12

Author(s):

Anying Yuan ◽

Hao Hu ◽

Qiupeng Yuan

Keyword(s):

Coal Seam ◽

Water Content ◽

Coal Mine ◽

Gas Diffusion ◽

Hard Coal ◽

Coal Seams ◽

Gas Emissions ◽

Soft Coal ◽

Pressure Water ◽

Gas Coal

At the present time, it is considered to be of major significance to study the gas emission law and stability controls of coal bodies in deeply buried high-gas coal seams. For this reason, in view of the specific problems of gas emissions caused by unstable rib spalling in coal mine walls, comprehensive research methods were adopted in this study, in order to conduct an in-depth examination of micropore structure parameters, gas desorption, diffusion laws, and coal stability levels. The results showed that the development degree of the pores above the micropores, as well as the small pores in soft coal seams, was better than those observed in hard coal seams. In addition, the gas outburst phenomenon was found to have more easily formed in the soft coal seams. The coal body of the No. 6 coal seam in the Xieqiao Coal Mine not only provided the conditions for gas adsorption but also provided dominant channels for gas diffusion and migration. The abnormal gas emissions of the No. 6 coal seam were jointly caused by the relatively developed pores above the small holes in the coal body, rib spalling of coal mine walls, and so on. The research results also revealed the evolution law of mechanical characteristics of the No. 6 coal seam under different water content conditions. It was found that the strength levels of the No. 6 coal seam first increased and then decreased with the increase in water content, and the water content level at the maximum strength of the coal seam was determined to be 7.09%. This study put forward a method which combined the water injection technology of long-term static pressure water injections in deep coal mining holes and real-time dynamic pressure water injections in shallower holes. Field experiments were successfully carried out.

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INFLUENCE OF ANALYSIS RESULTS OF ANALYTICAL COAL SAMPLES ON THE PREDICTION ACCURACY OF HAZARDOUS PROPERTIES OF COAL SEAMS

JOURNAL of Donetsk mining institute ◽

10.31474/1999-981x-2021-2-176-186 ◽

2021 ◽

pp. 176-186

Author(s):

Yevhen Rudniev ◽

◽

Vyacheslav Galchenko ◽

Elvira Filatieva ◽

Mykhailo Filatiev ◽

...

Keyword(s):

Coal Mine ◽

Calorific Value ◽

Mining Area ◽

The State ◽

Coal Seams ◽

Initial State ◽

Mining Operations ◽

Mineral Components ◽

Scientific Substantiation

Purpose: to establish possible quantitative errors in determining the values of some indicators of the degree of metamorphism without attracting the content of total moisture and mineral impurities to predict the hazardous properties of coal mine layers during mining. Methodology: based on the use of initial data on the quality indicators and properties of coals for specific coal seams, given in the reference sources, with the subsequent recalculation of the state of samples from their dry ashless or ashless state to the raw state. Comparison of the samples of indicators were determined, respectively, using analytical samples and based on the results of recalculation to the initial state (close to the production state), conclusions were drawn about possible errors in the case of using the analysis results of the analytical samples to predict hazardous properties of mines. Results: The analytical state of the samples for dry ashless state (daf) or wet ashless state (af) does not correspond to the state of coal in the working area of mining operations (r), which most accurately characterizes the manifestation of mine hazardous properties. The indicators of the release of volatile substances during thermal decomposition of coals, which are used to predict the hazardous properties of mine coal seams, do not directly reflect changes in the elemental composition of coals during metamorphic transformations. Methods for preparing analytical samples provide for grinding to small fractions, removing external moisture and enriching to ash content less than 10%, which does not correspond to the state of coal (r) in the mining area. The use of indicators set for dry ashless combustible (organic) mass excludes the possibility of analyzing the influence of moisture and mineral impurities on the manifestation of the hazardous properties of coal seams. The use of such indicators to predict the hazardous properties of mine coal seams can lead to errors in their determination of 45 ÷ 50%. The hazardous properties of coal seams can be adequately characterized only by the combined composition and properties of organic matter and mineral impurities in a state close to the presence of coal in the mining area. Using the example of possible significant errors in the calorific value, in the case of its use to characterize the hazardous properties of coal mine seams, the expediency of scientific substantiation of a set of indicators for a reliable forecast of a specific hazardous property for a specific seam formation was proved. Scientific novelty: hazardous properties of coal seams are reliably predicted on the basis of the composition and properties of organic and mineral components, reduced to conditions close to the state during mining operations. Practical value: the results obtained give grounds to scientifically substantiate the selection of the necessary indicators for predicting a specific hazardous property of coal seams and make proposals for improving the regulatory framework for the safe conduct of mining operations.

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