Twenty-seven gases and sixteen rock wastes from the thermal active Rymer coal waste dump were collected. The composition and origin of gaseous, liquid, and solid pollutants emitted during the self-heating process and the development of these processes with time were established. Gases were subjected to determination of molecular and stable isotope (δ¹³C and δ²H) composition. Rock-Eval pyrolysis and pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) were applied for evaluation of the quantity and molecular composition of pyrolysates released during the heating of rocks in temperatures from 100 to 650 °C. The main products of Py-GC-MS are released between 350 and 650 °C, namely alkanes, aromatic hydrocarbons, and aromatic alcohols. These components were also recorded in Py-GC-MS products of samples collected from the dump surface. Besides the high-molecular-weight organic compounds, in emitted gases CO₂, CO, gaseous hydrocarbons, and S-compounds were recorded. The stable isotope data indicated that methane was generated mainly during the low-temperature thermogenic process, but a share of the microbial-originated gas was visible. The source of the CO₂ was the oxidation of organic matter. The gaseous S-compounds were products of high-temperature decomposition of sulphides and organic S-compounds. The hydrocarbon and CO contents of the emitted gases proved to be good indicators for tracking of the self-heating processes.

Habitat and hydrocarbon potential of the Kimmeridgian strata in the central part of the Polish Lowlands

The open-pit exploitation of the Maritsa Iztok lignite field (Bulgaria) generated sedimentary waste rocks of low organic matter content that were deposited in internal dumps. Immediately after deposition the re-deposited sediments underwent weathering, including organic matter oxidation leading in some cases to self-heating. The aims of the research were to study the impact of weathering and self-heating on the maceral alterations in the dump site associated with the sediment re-deposition, and organic compounds identification and distribution. The 27 samples collected from Troyanovo-3 Mine internal dump differed in degree of alteration. The first group contained unaltered macerals and showed normal distribution of n-alkanes, phenols were absent and Rock-Eval Tmax ranged from 420 to 430 °C. The second group contained macerals with irregular cracks, paler oxidation rims, higher reflectance, Gaussian distribution of n-alkanes, high concentration of phenols and PAHs, and lowered Tmax values (below 400 °C). The samples contained elevated amount of pyrite which oxidation might contribute to self-hating.