Browsing by Author "Dreger, Marcin"

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Access status: Open Access ,
Changes in the methane emissions and hard coal output in the Brzeszcze mine (the Upper Silesian Coal Basin, Poland)
(Wydawnictwa AGH, 2020) Dreger, Marcin
The paper presents the variability of methane emissions in mining excavations in the Brzeszcze mine (Poland) against the background of hard coal output, geological and mining factors. The geological structure of the Upper Silesian Coal Basin (USCB) is very diverse. The Brzeszcze coal deposit is located close to the large and permeable Jawiszowice fault which increases the methane hazard during mining activities performed close to this fault. The overall decrease in hard coal output (1988–2018) has coincided with a rapid increase in methane emissions (1997–2018). Throughout the study period, hard coal output decreased threefold from 3.9 to 1.2 million Mg annually. Coal extraction in high methane content beds (e.g. 510, 405/1, 364, 352) increases the total methane ($CH_{4}$) emission into mining excavations, aggravating the methane hazard due to the high explosiveness of the gas. To protect miners, coal workings need to be continuously ventilated, taking the harmful gas out of the mine (ventilation air methane emission) or methane needs to be captured by underground methane systems (degassing). Every year, over 34 million m$^{3}$ of $CH_{4}$ is captured by the drainage systems and over 70 million m$^{3}$ $CH_{4}$ (average) is discharged through ventilation shafts into the atmosphere. The presence of the large, permeable regional dislocation, the Jawiszowice fault zone, shaped the methane concentration in the fault vicinity, when the highest methane emissions during coal mining was studied.
Access status: Open Access ,
Methane emissions in selected hard-coal mines of the Upper Silesian Coal Basin in 1997–2016
(Wydawnictwa AGH, 2019) Dreger, Marcin
Hard coal is extracted in the Upper Silesian Coal Basin (USCB) from deeper and deeper coal seams every year. In 2000, the average depth of coal extraction was 600 m, in 2010 – 700 m, but in the last two years (2016–2017) this has been extended to a depth of 770 m. The USCB is not homogeneous in layout in terms of methane hazard, but rather very diverse. Therefore, the USCB has been divided into seven gassy regions to show differences in methane danger distribution. Northern and central USCB regions (I, II and III) are the mostly naturally degassed, so the most dangerous gassy conditions are in the IV and V regions, where methane content in coal seams varies from 6 m$^{3}$/Mg coaldafto above 18 m$^{3}$/Mg coal$^{daf}$. The two westernmost USCB gassy regions (VI and VII) are poorer in methane than the IV and V areas. Six representative coal mines were chosen: Mysłowice-Wesoła, Budryk, Brzeszcze, Pniówek, Marcel and Rydułtowy-Anna based on their high hard coal production and total methane emissions. The reason for the highest methane emission in those regions might be fault tectonics facilitating methane migration and also the thick and continuous Miocene cover constituting a hermetic screen for gases in the southern part of the USCB.