Open pit coal mining is a global problem, because mines occupy large areas that completely change the relief, dramatically affect ecosystems, as a result of which they lose most of their functions, and a significant part of the fertile soil degrades and becomes unsuitable for agricultural activities. In the presented work, the initial stage of soil formation was studied, the parameters of the granulometric composition of uneven-aged rocks of Donbas mine dumps, their nutritional regime, and the species composition of soil algae were studied. Samples were taken from three different-aged rock dumps of the mines: ˮSouth-Donbaska-3ˮ (rock storage for 40 years); ˮSouth-Donbaska - 1ˮ (storage of rock for 52 years), ˮTrudovska №5 - bis (storage of rock for more than 100 years). The agrochemical parameters of the rock were determined in the samples: pHwater, humus, nitrate nitrogen, mobile phosphorus, exchangeable potassium, particle size distribution. The determination of granulometric fractions of 0-20 cm layer of rock dumps of the mines shows, along with the age, a potential increase of the dump of fine fractions and a decrease in the fraction of stones from 83% in the dump of the South- Donbaska mine, and by 30 to 64.7% in the dump of the Trudovska № 5-bis. The proportion of the clay fraction is not high in all dumps and it does not exceed 1%, but its appearance indicates the initial stage of a soil structure formation. Soil formation begins with the colonization of mineral rocks with soil algae. The species composition of soil algae, the quantitative accounting were determined by microscopy of a freshly selected soil sample and by cultural methods. Algae species were determined by determinants. In the rock dump, the structure of algal groups becomes more similar to, their structure in the background soils of the territory. The dominance of the representatives of Chlorophyta and Cyanophyta in the rock indicates the steppe process of soil formation. The data obtained contribute to the expansion of the ecological and biological understanding of the initial stages of the formation of soil cenoses.