Waste dumps rehabilitation measures based on physico-chemical analyses in Z ghid mining area (S laj County, Romania)

The present study deals with an abandoned coal mine from Z ghid area, North-WesternTransylvanian Basin (S laj County). The mining activity was stopped in 2005, without any attempt ofecological rehabilitation of the mined area and especially of the waste dumps left behind. The proposedrehabilitation models are based on some physical-chemical analyses of soil and waste samples (e.g. pH,EC, Salinity, humidity, porosity, density, plasticity, organic substances, mineralogical composition, heavymetals). Erosion map has been drawn based on the determined mineralogical composition (accordingSTAS 1913/5-85 – using Galton curve) of tailings and the soil type. The values obtained for moisture andplasticity have been used to determine the ideal general inclination angle of the landfill systems in thestudied perimeter. Through chemical analysis, heavy metals like Ni and Cu have been identified, as themain pollution factors for surface and underground water. Therefore, the concentration of heavy metalsin the waters from Z ghid area is high in the water bodies, which are formed on waste dumps, but alsoin the mine water. This analysis is useful in establishing the actual state of the waste dumps and theircontent and the negative effects, which exercise on the environment in order to select the rehabilitationmodel for the waste dumps from Z ghid mining area. The main measures consist in: waste dumpsleveling, soil remediation, perennial plants culture and acid mine water decontamination.