The paper focused on the formation mechanisms of the geochemical soi background for a wide range of elements. Three areas in Siberia of the coal mining spoils were investigated. The spoils were recultivated 30 years ago by applying a homogenous layer of loamy bedrock as a potentially fertile substrate and then left for spontaneous revegetation. The assessment was conducted using bulk concentrations of the elements. Since there is no excess in concentrations of heavy metals and radionuclides in the recultivated spoils, forming soils also contain permissible concentrations of these elements. The change in mineral composition in rocks of the spoils has been shown: decrease in the carbonate content, in some cases the mica and illite-smectite share increases. Siderite dissolution was followed by the carbonate-ion removal and gematite crystallization. The formed heavy metal background in technosols falled within the range of background soils, which are abundant in the territory. Recultivated sites could be argued as environmentally safe.