کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1753253 1522579 2013 16 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Distribution of methane and carbon dioxide concentrations in the near-surface zone and their genetic characterization at the abandoned “Nowa Ruda” coal mine (Lower Silesian Coal Basin, SW Poland)
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات زمین شناسی اقتصادی
پیش نمایش صفحه اول مقاله
Distribution of methane and carbon dioxide concentrations in the near-surface zone and their genetic characterization at the abandoned “Nowa Ruda” coal mine (Lower Silesian Coal Basin, SW Poland)
چکیده انگلیسی
The closure of hard coal mines in the Lower Silesian Coal Basin (SW Poland) resulted in migration of coal-bed gases (mostly methane and carbon dioxide) towards the surface. The gases were driven out by rising groundwater table in the Pennsylvanian aquifer (so-called “water piston effect”). Because such migration may be a hazard for inhabitants living in the post-mining lands a surface geochemical survey was carried out in the area of the closed “Nowa Ruda” hard coal mine. The research aimed at: (i) evaluating the distribution of methane and carbon dioxide concentrations in the near-surface zone, (ii) determining the genetic characteristics of soil gases and (iii) comparing their characteristics with that of coal-bed gases. The surface geochemical survey included sampling of soil gases and chromatographic analyses of samples for methane and carbon dioxide concentrations and for stable carbon isotope composition in samples of increased methane and carbon dioxide concentrations. Samples were collected along 8 sampling lines located in the mining fields “Piast”, “Słupiec” and “Wacław”. In total, 390 soil gas samples were collected from 1.2 m depth. Maximum methane and carbon dioxide concentrations were 7.8 and 5.8 vol.%, respectively. Almost all methane encountered in the analyzed samples of soil gases are of microbial origin and were generated during recent anaerobic processes in the near-surface zone. High concentration of carbon dioxide was generated by aerobic biodegradation of organic matter in abandoned mines. Moreover, carbon dioxide was originated during the near-surface oxidation of methane. Only sometimes insignificant thermogenic component of coal-bed methane and carbon dioxide which migrated to near-surface zone from Pennsylvanian coal-bed strata occurs. Moreover an insignificant component of endogenic carbon dioxide also migrated though the faults from deep-seated volcanic chambers and/or even from upper mantle in the “Piast” mining field. The results of our research revealed that the changes of soils gas concentrations in the “Słupiec” field do not indicate “water piston effect”. The highest state of gas emergency by inflow of deep-gases to near-surface zone could take place in the years 2008-2010 therefore much later than the near-surface measurement sessions in 2004. In the “Piast” field a relatively high number of anomalous concentrations of methane and carbon dioxide were measured. Such values results from degassing of groundwaters, the table of which stabilized within the Pennsylvanian aquifer in 2000. Gases migrated towards the surface along the fracture systems and faults, particularly along the Main and the Great faults. A great number of anomalously high carbon dioxide concentrations were measured in the “Wacław” field, which is an effect of groundwater table stabilization within the Pennsylvanian rocks. Carbon dioxide migrates towards the surface along the bedding planes of Pennsylvanian coal-bearing strata and along the linings of remediated “Wacław” and “Wanda” shafts. The highest state of gas emergency by inflow of deep-gases to near-surface zone caused by the uprising of Pennsylvanian water table (“piston effect”) could take place in “Piast” mining field in the years 1998-2000, and in “Wacław” mining field in the years 1978-1980, therefore much earlier than the near-surface measurement sessions in 2004.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: International Journal of Coal Geology - Volumes 116–117, 1 September 2013, Pages 1-16
نویسندگان
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