Geochemical and stable carbon isotopic composition of coal-related gases from the SW Upper Silesian Coal Basin, Czech Republic

► Geochemical and 13C composition of coal-related gas from boreholes and canisters analyzed. ► Results indicate gas origin from thermogenic and microbial processes. ► Gas composition is altered by methane oxidation processes during canister desorption. ► No consistent isotopic fractionation from desorption observed.