The paper analyses and generalises the scientific data for the period of 1980–2016 concerning soil formation processes and restoration of the ecosystems on re-cultivated fields that had been destroyed by the biggest coal mine in Bulgaria. To analyse how these processes flow under grass and woody vegetation, and agriculture use on the oldest embankment Zapad–Iztok of Maritsa–Iztok Mine have been completed:(1) Analysis of the ecological conditions of the reclaimed embankments–climate, natural soils and materials from the soil depots for reclamation, and (2) Analysis of chemical and physicochemical properties of the embankments after biological reclamation with different soil formation period. From the results of the study on the embankment materials of the oldest embankment Maritsa–Iztok have been made deductions about soils formation process under the influence of the grass and woody vegetation after 20–25 and 40 years of forest and agricultural reclamation. Based on the study shall be developed a conception for a restoration of damaged terrains and broadly applicable technology for biological reclamation.