Environmental anthropogenic transformation leads to technogenic landscapes emergence, characterized by complete or partial destruction of ecosystem components. Partial restoration of biodiversity is possible through reclamation and self-overgrowing. Formation of vegetation cover on technogenic landscapes – a process that takes place in three syngenesis stages. This article presents the results of studying the degree of self-overgrowing on iron ore industry dumps in the Kostanay region (SSGPO JSC and Kachary Ruda JSC) at the stage of a group-thicket community – the second stage of syngenesis. Sixty-three geobotanical descriptions were compiled, and group-thicket communities were found in twenty-six. A group-thicket community is usually formed by patients; certain relationships and mutual influence appear between plants, but they remain fragmentary, individuals are slightly interconnected trophically. The predominance of species with a wide ecological amplitude characterizes this stage. It was found that the rate and patterns of vegetation cover formation at the second stage of syngenesis differ on saline and non-saline soils: the former are dominated by halophytes and long-rhizomatous plants, the latter are characterized by long-rhizomatous plants; moreover, the activity of species on the first soils is much higher than on the second ones, the number of species is approximately the same on both soil types.