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During the coal mining process, large amounts of mining waste are produced and disposed of on the surface. This could result in significant quantities of toxic substances being released into the environment. The research material consisted of sedimentary rocks from the Lublin Coal Basin, which are potential waste geomaterial. The research included the chemical composition (SiO2, Al2O3, Fe2O3, CaO, Na2O, K2O, P2O5, MnO, TiO2, and Cr2O3 contents) obtained by XRF and the concentrations of potentially toxic elements (PTEs), such as As, Cd, Cu, Cr, Ni, Pb, and Zn, analyzed by ICP/MS The contents of total carbon and total sulfur obtained by the LECO analyzer. Furthermore, the article discusses the associations between toxic elements, as well as between toxic elements and Al, Si, (TOT/C), and (TOT/S). Analysis of potentially toxic elements (PTEs) as well as Fe concentrations revealed significant heterogeneity in the distribution of these elements in the vertical profile of the formation. The results indicated that the concentrations of toxic elements were As (1–25 ppm), Cd (0.1–0.3 ppm), Cu (2.1–77.9 ppm), Cr (21–179 ppm), Ni (11.2–230.1 ppm), Pb (10.0–52.8 ppm), and Zn (13–178 ppm). It was also found that PTEs concentrations are lower than the permissible values in soils, even in urban and recreational areas (in accordance with Polish legal standards). This indicates that the potential mining waste is not hazardous to the environment during its disposal or utilization.

The Upper Silesian Coal Basin (USCB), located in southern Poland, is the major coal basin in Poland, and all technological types of hard coal, including coking coal, are exploited. It is also an area of high potential for coal-bed methane (CBM). Despite the increasing availability of alternative energy sources globally, it is a fact that the use of fossil fuels will remain necessary for the next few decades. Therefore, research on coal-bearing formations using modern research methods is still very important. The application of geochemistry and chemostratigraphy in reservoir characterization has become increasingly common in recent years. This paper presents the possibility of applying chemostratigraphic techniques to the study of the Carboniferous coal-bearing succession of the Upper Silesian Coal Basin. The material studied comes from 121 core samples (depth 481–1298 m), representing the Mudstone Series (Westphalian A, B). Major oxide concentrations of Al2O3, SiO2, Fe2O3, P2O5, K2O, MgO, CaO, Na2O, K2O, MnO, TiO2, and Cr2O3 were obtained using X-ray fluorescence (XRF) spectrometry. Trace elements were analyzed using inductively coupled plasma mass spectrometry (ICP/MS). The geochemical record from the Mudstone Series shows changes in the concentration of major elements and selected trace elements, leading to the identification of four chemostratigraphic units. These units differ primarily in the content of Fe, Ca, Mg, Mn, and P as well as the concentration of Zr, Hf, Nb, Ta, and Ti. The study also discusses quartz origin (based on SiO2 and TiO2), sediment provenance and source-area rock compositions (based on Al2O3/ TiO2, TiO2/Zr, and La/Th), and paleoredox conditions (based on V/Cr, Ni/Co, U/Th, (Cu+Mo)/Zn, and Sr/Ba) for the chemostratigraphic units. Chemostratigraphy was used for the first time in the study of the Carboniferous coal-bearing series of the USCB, concluding that it can be used as an effective stratigraphic tool and provide new information on the possibility of correlating barren sequences of the coal-bearing succession.