Upper Silesian Mineral Coal Basin

UPPER SILESIAN MINERAL COAL BASIN (RU: Верхнесилезский каменноугольный бассейн) is the large coal basin within Poland. This basin is situated within the Katowice and Krakow provinces, on the Upper Silesian lowland, which is fringed at the north-west by the Sudeten mountains, and at the north-east by the Świętokrzyskie mountains. The area of the basin is approximately 6500 square kilometres, of which approximately 1000 square kilometres are accounted for its southern part within Czechoslovakia, which is distinguished under the name of the Ostrava-Karviná basin. The total reserves within the basin to the depth of 1000 metres are calculated at 100 billion tonnes.

The coal-bearing depositions of the Lower and Middle Carboniferous (Namur-Westphal) fill the large trough, which is dipping into the south-eastern direction. The thickness of these depositions increases from west to east, from 2500 to 6000 metres. On the area of approximately 1200 square kilometres within the northern and western parts of the basin, the coal-bearing rocks emerge onto the surface or under the thin (5-20 metres) cover of the Quaternary depositions, while on the remaining area, these rocks are overlain with the marine formations of the Triassic, Jurassic, and Miocene, with the total thickness of several hundred metres.

There have been unsealed within the coal-bearing stratum more than 450 coal layers and interlayers, of which there are up to 200 layers with the thickness of more than 0.5 metres. There is most coal-saturated the middle part of the cross section (the Ruda and Siedlce stratigraphic suites) with the thickness of up to 1000 metres, within which there are contained up to 30 layers with the average thickness of 1-2 metres, and the unique layers with the thickness of 7 and 24 metres. The coal-bearing capacity decreases itself from west to east, and along the same direction, there proceed the splitting and thinning of the layers. The north-western part of the basin is folded into the narrow folds of the sub-meridional strike with the numerous reverse faults. To the south and east, there are well developed the slightly inclined brachymorphic structures, which have been disrupted by the dip-slip faults, which are creating the small block structure within the certain places. The coals are humic, with the homogeneous petrographic composition, but there may be often found within the top parts of the coal layers the interlayers of the cannel coals. The degree of the metamorphism of the coals increases itself from east to west.

The development of the coals is conducted mostly within the Rybnik-Gliwice (the western part of the basin) and Central (the northern part) industrial regions, where are contained the high quality sintering coals of the GZh, Zh, and K marks. There is also involved into the industrial mastering the Krakow (eastern) region with the coals of the D and G marks. The coals are prevalently of the low-ash type (Ac = 3-8%). The gas-bearing capacity is weak, and, within the unsealed part of the basin, it increases itself into the southern direction. The water-bearing capacity of the rocks of the Carboniferous is low, while there have the high water abundance the rocks of the Triassic, Jurassic, and Miocene. The Upper Silesian mineral coal basin accounts for approximately 98% of the total extraction of the mineral coal within Poland. The extraction is conducted using the underground method. The major indicators of the underground mines within the basin (1980) are: the extraction of the marketable coal is 182.6 million tonnes; the average depth for the development is 498 metres; the share of the extraction from the depth of more than 600 metres is 21.5%. The distribution of the extraction throughout the thickness of the layers is 13.8% up to 1.5 metres, 56.9% from 1.5 to 3.5 metres, and 29.3% more than 3.5 metres. There are beneficiated all the coking coal, and the significant portion of the energetic coal. The coal, which has been beneficiated, amounts to 55% within the total marketable extraction. The largest underground mines are the "Mine named after Lenin" (the productive capacity is 24 thousand tonnes per day) and "Piast" (16 thousand tonnes per day).