Budowa petrograficzna i stopień uwęglenia witrytu z kopalni Siersza (GZW)

Wiesław Gabzdyl, Bronisława Hanak

Abstract


 Petrograficznie zbadano witryt z pokładów kopalni Siersza (GZW) i określono jego stopień uwęglenia. Stwierdzono liczne przejawy budowy petrograficznej charakterystyczne dla twardego węgla brunatnego oraz zróżnicowane przejawy procesu żelifikacji, właściwego w procesie uwęglenia stadium węgla brunatnego. Niski stopień uwęglenia potwierdziły wyniki pomiarów średniej zdolności odbicia światła (Rom) macerałów i submacerałów grupy witrynitu. Wykazano, ze w GZW, obok węgla kamiennego, występuje węgiel o cechach chemicznych, fizycznych i petrograficznych odpowiadających twardemu węglowi brunatnemu, ukształtowanemu w fazie wczesnej katagenezy i w zmieniających się warunkach facjalnych.

 

PETROGRAPHIC STRUCTURE AND DEGREE OF COALIFICATION OF VITRITE FROM THE SIERSZA MINE (UPPER SILESIAN COAL BASIN)

                                                                                                                                     

Vitrite occurring in coal seams in the Siersza mine (Upper Silesian Coal Basin) yields 73.40–74.83% Cdaf, 4.79–5.08 Hdaf, 1.17–1.26 Ndafand 18.83–20.64 Odaf(Table 1). After powdering, it reacts with 10% KOH similarly as brown coal. Content of vitrite in the studied seams 207, 208, 209/210, 214 and 301 ranges from 20 to 30%. Coals of these seams are characterized by content of volatile matter (Vdaf) equal 42–47%, calorific value (QdafS) 28–31 MJ/kg and mean capability of vitrinite to reflectance (R0m) ranging from 0.47 to 0.53%.

Low degree et coalif1cation brings the coals to an intermediate position between black and brown ones. Such position is also shown by the studies on vitrite under reflected light and measurements of mean capability of macerals and submacerals of the vitrinite group to reflectance (R0m).

Vitrite was found to yield mainly telinite and telocollinite, gelocollinite, corpocollinite and desmocollinite. There were also found micrinite, resinite and mineral components. Telinite and telocollinite are varying in degree of gelification which makes possible identification of their varieties A and B. Telinite and telocollinite were often found to be microscopically very close to humotelinite from hard brown coals, especially textoulminite and euulrninite. Telinite (textoulminite) was also found to yield relics of flobafinite, known to occur in brown coal. Varieties A are characterized by dark-grey colours, relics of cellular structure and high degree of gelification, and B – light-gray colours, well-preserved cellular structure and generally lower degree of gelification. The strongest effects of gelification include the presence of gelocollinite in the form of cell space infillings in telinite. Mean capability of vitrinite to reflectance (R0m)  is markedly varying, from 0.35 to 0.77%. The widest range of the values R0m was found in corpocollinite (0.44–0.77%) and the lowest – in telinite A, telocollinite A, gelocollinite as well as desmocollinite. The values obtained for telinite B, telocollinite B and, on small scale, desmocollinite, are somewhat higher (0.47–0.65%). The obtained values (R0m) correspond to those typical some hard brown coals.

The studies showed the coals from the Siersza mine to display chemical, physical and petrographic features of hard brown coals. The coals were shaped in early catagenetic stage and they were not subjected to any significant influence of high temperature and pressure conditions. However, it appears necessary to study eventual effects of facies (Eh and pH) and geotectonic conditions on structure of vitrite and chemical-mineral composition of mineral matter, especially huminians.

 


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