Natural stabilization of mine waste-dumps — Evolution of the vegetation cover in distinctive geochemical and mineralogical environments

The present work is focused on remediation promoted by natural vegetation at distinctive mine waste-dumps. Three mines, located in different climatic, hydrological, and paragenetic environments, were selected as case studies (Cerdeirinha, Lapa Grande and Penedono, N Portugal). They were analyzed with the following objectives: i) mapping of cover vegetation to monitor the success of environmental rehabilitation; ii) to estimate the value of local flora for regional phytostabilization; and iii) to study the influence of geochemical and mineralogical parameters for the establishment of spontaneous vegetation. Remote detection tools showed the effective mapping of the evolution of the vegetation for a thirty year period (between 1980 and 2011). Results also suggest that the ore deposits have a strong influence on the evolution of the mine wastes and, consequently, on the establishment of conditions for sustainable revegetation. A complex ore paragenesis, the presence of varied clay minerals and geochemical evolution of the wastes in order to form stable supergenic minerals, seem to enhance the potential for successful revegetation. Combining information regarding environmental mineralogy with data about substrate and vegetation allows the monitoring of the evolution of distinctive mining environments and the recommendation of the appropriate species for phytostabilization purposes. ► Study remediation promoted by natural vegetation at distinctive mine waste-dumps. ► Inventory of spontaneous vegetation for phytoremediation. ► Ore deposits have a strong influence on the evolution of mine wastes. ► Each site has a specific association of plants.