Ash concentration in hard coal and its natural gamma radioactivity

The subject mater of this paper is correlation between ash content of hard coal and its radioactivity for selected mines in Upper Silesian Coal Basin (USCB), Poland. In this region both the inorganic part of coal and waste rock (clays, shales, mudstones) contain significant amounts of natural radioactive elements (nuclides) whereas the organic part of coal is practically deprived of them. Therefore, almost the entire natural radioactivity of coal is related to its ash content and, consequently, there should be a correlation between these values. On the other hand, coal deposits, which were formed in different geological conditions, may differ by their mineralogical compositions, both of its inorganic part and waste rock. This results in occurrence of regional properties of hard coal; also parameters describing natural radioactivity are differentiated regionally. The authors described quantitatively the correlation between ash content in coal and its radioactivity. (author)