Minimising Coal Mining’s Impact on Biodiversity: Artificial Soils for Post-Mining Land Reclamation

Abstract

Coal mining and the energy industry generate large amounts of solid waste, which must be disposed of in landfills and lead to numerous environmental problems. This paper presents a method for creating artificial soil mixtures based on an EU-funded international research project called RECOVERY. The main idea behind the proposed solution is the safe use of coal combustion by-products (energetic slag and decarbonation lime), mining waste (aggregate and sealing material) and spent mushroom compost as components for creating artificial soils. Laboratory tests of the soil substitutes showed low concentrations of heavy metals and high macronutrient content, adequate for proper plant growth. As a result of a two-year study on the application of soil cover on a 4000 m2 testing ground, species characteristics for the mesotrophic, dry meadow, ruderal and segregated vegetation were found. In the second year of the in situ study, an apparent reduction in soil salinity was observed. The principal component analysis confirmed that decreasing soil salinity positively affected ruderal and dry meadow species. In contrast, high salinity levels showed no adverse effect on mesotrophic meadow vegetation. The results demonstrated that applying soil covers elaborated from industrial by-products is valuable for recovering high-acidity coal mine waste heaps.