Natural radioactivity studies of rocks from hard coal basin

The aim of this work was to examine whether the nuclear spectrometric well-logging methods, utilizing both gamma-ray and neutron sources, which have been applied in the geophysical exploration of the Upper Silesia Coal Basin in Poland, could be replaced by a simple scintillation spectrometry of the natural gamma-ray background measured in the boreholes. Therefore, it was necessary to measure gamma radioactivity in borecore samples and to try to establish its relation to the lithology of rocks and to hard coal parameters, i.e., ash content, calorific value, and carbon content. The ratios of the concentrations of uranium, thorium, and potassium make it possible to differentiate the lithological types of the rocks, and give information about the sedimentary processes of the basin. This was confirmed by the first well-logging results