scholarly journals The Seismic Source Parameters of Tremors Provoked by Long-Hole Destress Blasting Executed During the Longwall Mining of a Coal Seam Under Variable Stress Conditions

2020 ◽  
Vol 177 (12) ◽  
pp. 5723-5739
Author(s):  
Łukasz Wojtecki ◽  
Maciej J. Mendecki ◽  
Iwona Gołda ◽  
Wacław M. Zuberek
Keyword(s):  
Longwall Mining ◽  
Source Parameters ◽  
Seismic Source ◽  
Hard Coal ◽  
Coal Seams ◽  
Coal Basin ◽  
Rockburst Hazard ◽  
Seismic Source Parameters ◽  
Upper Silesian Coal Basin ◽  
Destress Blasting

AbstractThe underground mining of coal seams in the Upper Silesian Coal Basin is carried out at great depths and mostly in the presence of remnants or edges of other surrounding coal seams, i.e. under the condition of high stress level in the rock mass. Therefore, this mining is accompanied by rockburst hazard and suitable preventive action is required. Long-hole destress blasting plays an important role and is commonly applied in rockburst prevention in underground hard coal mines. Estimated blasting effectiveness is important when designing rockburst prevention. It is commonly estimated on the basis of the seismic energy of a provoked tremor. The seismic source parameters have already been considered for this purpose. Additional information about the effects of long-hole destress blasting could be contemplated in the planning of active rockburst prevention. The seismic source parameters of tremors provoked by long-hole destress blasting have been calculated and are presented in this article. Destress blasts were performed during the longwall mining of coal seam no. 506 in one of the hard coal mines in the Upper Silesian Coal Basin. They were executed from the longwall face, in order to destress the rock mass ahead of it. Parameters of the blasts were variable and they were modified according to geological and mining conditions and the observed level of rockburst hazard. The seismic source parameters have been determined for tremors provoked directly after firing explosives and for tremors occurring in the waiting time, and they have been compared with each other.

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

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.

scholarly journals Determination of Destress Blasting Effectiveness Using Seismic Source Parameters

2017 ◽  
Vol 50 (12) ◽  
pp. 3233-3244 ◽  
Author(s):  
Łukasz Wojtecki ◽  
Maciej J. Mendecki ◽  
Wacaław M. Zuberek
Keyword(s):  
Source Parameters ◽  
Seismic Source ◽  
Seismic Source Parameters ◽  
Destress Blasting

scholarly journals Methane emissions and demethanation of coal mines in the Upper Silesian Coal Basin between 1997 and 2016

2019 ◽  
Vol 7 (1) ◽  
pp. 12-23 ◽  
Author(s):  
Marcin Dreger ◽  
Sławomir Kędzior
Keyword(s):  
Methane Emission ◽  
Methane Emissions ◽  
Coal Extraction ◽  
Hard Coal ◽  
Coal Seams ◽  
Coal Basin ◽  
Upper Silesian Coal Basin ◽  
Near Future ◽  
Research Period ◽  
Modern Technologies

Abstract Between 1997 and 2016 we observed important changes in hard coal extraction and methane emission in the Upper Silesian Coal Basin. Hard coal extraction in the near future will be very dangerous because it will be necessary to reach deeper methane-rich coal seams. Permanent monitoring of the volume of emitted and captured methane is necessary to combat the methane hazard. The predictability of gaseous hazards are important in order to keep underground work safe. We gathered and analysed data from three coal companies: Katowice Coal Holding, the Coal Company, Jastrzębie Coal Company and in the whole of the Upper Silesian Coal Basin for the last twenty years and this allowed us to notice changes and CH4 trends in ventilation emission and demethanation. There is a decrease in the extraction of hard coal from year to year. At the same time there is an increase in the total methane emissions which forces actions aimed to effective contracting the methane hazard. Specifically, methane emission has been increasing for years, making hard coal extraction very dangerous. We observed increases in CH4 vent emission and volume of methane coming from underground drainage systems. Much more methane is released during hard coal extraction at deeper mine levels. Throughout the entire research period the methane hazard increased. Therefore, the development of modern technologies for methane capturing should contribute to improvement of hazardous conditions for coal mining in the basin.

scholarly journals Sulphides in Hard Coal Seams from the Orzesze Beds s.s. of Mudstone Series (Westphalian B) in the Eastern Part of the Upper Silesian Coal Basin

2016 ◽  
Vol 32 (3) ◽  
pp. 23-38
Author(s):  
Barbara Bielowicz ◽  
Jacek Misiak
Keyword(s):  
Hard Coal ◽  
Titanium Oxides ◽  
Iron Sulfides ◽  
Coal Seams ◽  
Coal Basin ◽  
Framboidal Pyrite ◽  
Coal Deposits ◽  
Upper Silesian Coal Basin ◽  
Iron Sulphides ◽  
Sulfur In Coal

Abstract Due to dynamic climatic changes resulting, among others, from the use of coal, the content of harmful substances in coal is of particular importance. Dangerous air pollution resulting from the burning of coal (e.g. As, Se, Hg, Pb, Sb) is often associated with sulfide minerals in coal. The study focused on the sulphides occurring in Polish hard coal deposits. Sulfides are one of the forms of occurrence of sulfur in coal. In this paper, an emphasis has been placed on on the characteristics of forms of occurrence of sulphides on both macroscopic and microscopic scale and on the chemical analysis in the micro area. The study has been conducted for the No. 301–308 seams from the eastern part of the Upper Silesian Coal Basin, stratigraphically belonging to the highest part of the Orzesze Beds s.s. (Westphalian B). The coal samples have been collected from the coal seams in the underground excavations of the following coal mines: Jan Kanty, Sobieski Jaworzno I, Wesoła and Ziemowit hard coal mine. Iron sulfides (pyrite, marcasite) in coal seams of the Orzesze Beds s.s. form various forms of macroscopically visible aggregates. These include massive, vein, pocket-like (impregnation) or dispersed forms. On the basis of microscopic observations, the following forms of occurence of iron sulphides in the tested coal have been determined: skeletal and massive vein forms, massive pocket-like (impregnation) forms, framboidal pyrite and euhedral crystals. The most common form of sulfides in the studied coal seams are vein forms cutting across bedding, usually creating complex dendritic and skeletal forms. Iron sulfides often occur in pocket-like (impregnation) forms, not directly linked with vein forms and fusinite. The WDS analysis in the micro area has revealed the chemical composition of sulfides in eight coal samples. As follows from the analysis, the tested coal seams are dominated by FeS2 iron sulfides. It has been shown that the iron sulfides contained small admixtures of Pb, Hg, Zn, Cu, Ag, Co Sb and Ni. The admixtures of As and Cd have been observed only in individual minerals. Lead, reaching up to 1.06%, has the highest concentration out of all admixtures in pyrite and marcasite. Small amounts of galena, titanium oxides (rutile), monazite and barite have also been found in the tested coal samples. Locally, vein forms, pyrite and dolomite were interlaying each other; the same applies to pyrite and apatite. In addition, dolomite fills part of the cells in fusinite.

Estimating the accuracy of source “parameters”

1967 ◽  
Vol 57 (3) ◽  
pp. 373-379 ◽  
Author(s):  
Helen W. Freedman
Keyword(s):  
Standard Error ◽  
Source Parameters ◽  
Seismic Source ◽  
Origin Time ◽  
Intermediate Depth ◽  
Seismic Source Parameters ◽  
Space And Time

abstract This paper suggests a method for estimating the errors accompanying estimates of seismic source parameters. While the method is a general one, the data here are from 1962 and 1963 and special attention is given to a few regions, such as the Kuriles. The overall standard error of about one-half a degree in each coordinate and four seconds in origin time are broken down and analyzed in terms of magnitude, depth, and location in space and time. The most accurately located earthquakes appear to be those of intermediate depth and magnitude in highly seismic areas. There is some indication that these errors are decreasing with time.

Volcanoclastic minerals of some Czechoslovakian tonsteins and their alteration

Clay Minerals ◽  
1992 ◽  
Vol 27 (3) ◽  
pp. 269-282 ◽  
Author(s):  
Z. Weiss ◽  
A. Baronnet ◽  
M. Chmielova
Keyword(s):  
Coal Seams ◽  
Coal Basin ◽  
Upper Carboniferous ◽  
Upper Silesian Coal Basin ◽  
Mineral Assemblages ◽  
Clayey Rocks ◽  
Quartz Grains

AbstractIn the Czechoslovak part of the Upper Silesian Coal Basin (Ostrava-Karvina Coal Basin), only part of the Upper Carboniferous (Namurian A, B, C and Westphalian A) is well developed, and tonsteins, which are clayey rocks or claystones, occur as thin, clayey interlayers in the coal seams. Two types of primary volcanic mineral assemblages were identified in four tonstein samples from different coal seams; the first type is characterized by the presence of biotite and sanidine, and the second by the presence of biotite, bytownite and Ca-amphibole. All tonsteins studied contained kaolinite minerals, volcanic quartz grains, crystals of zircon and apatite. Separated biotite flakes with an admixture of kaolinite layers were identified as 1M polytype. The flakes without kaolinite minerals were identified as epitactic overgrowth of 1M and complex polytypes, and twinned crystals of 2M1 polytype. Kaolinization of biotite flakes was observed in all tonstein samples studied. Kaolinite single layers (7 Å) as well as two-layer polytype of kaolinite minerals (14 Å) sandwiched between biotite layers (10 Å) were identified by HRTEM imaging.

scholarly journals Structurally Altered Hard Coal in the Areas of Tectonic Disturbances – An Initial Attempt at Classification

2016 ◽  
Vol 61 (3) ◽  
pp. 677-694 ◽  
Author(s):  
Katarzyna Godyń
Keyword(s):  
Optical Methods ◽  
Hard Coal ◽  
Original Structure ◽  
Coal Seams ◽  
Initial Attempt ◽  
Near Fault ◽  
Upper Silesian Coal Basin ◽  
Tectonic Disturbances ◽  
Coal Degradation ◽  
Tectonic Dislocations

Abstract As regards the exploitation of hard coal seams, the near-fault zones and faults themselves are considered to be particularly dangerous areas, which is due to a high probability of the occurrence of gasogeodynamic phenomena. Tectonic dislocations running across a seam have a destructive impact on coal. Degradation of the coal structure, particularly visible in the microscale, is reflected in the coal’s strength or gas properties. Such “structurally altered” coal is characterized by the presence of numerous fracturings, crushed areas, or dislocations of some of its fragments, and sometimes even the total destruction of the original structure. The present paper provides a detailed analysis and description of near-fault coal obtained from selected seams of the Upper Silesian Coal Basin, completed due to the application of optical methods. Both the type and the degree of changes in the structure of such coal were identified. On this basis, the author attempted to systematize the nomenclature used in relation to selected Upper Silesian hard coal seams, which, in turn, resulted in a proposed classification of the “altered structures” of the near-fault coal.

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