Attending the 12th International Conference on Mine Closure

Last September, the 12th International Conference on Mine Closure was celebrated in Leipzig (Germany). This conference, organized by the Technical University Bergakademie Freiberg, is one of the world`s reference events among the mine closure professionals. The main conference topics that were discussed and that have been found as the main issues were:  establishing integrated life of mine planning, design sustainable land uses from the social and environmental perspective, increasing the post-mining assets value, and establishing  stable and self-regenerating ecosystems, among others.

Due to the urgent necessity of improving reclamation of mining areas, abandoned and/ or in transition to close, researchers from IRNAS-CSIC, University of Seville, University of Reading and Haute École Condorcet have collaborated to present a paper and an oral communication in this conference.

Gil-Martínez M, Domínguez MT, Navarro-Fernández CM, Crompot H, Tibbett M , Marañón T (2018). Long-term effects of trace elements contamination on soil microbial biomass and enzyme activities, in C Drebenstedt, F von Bismarck, A Fourie & M Tibbett (eds), Proceedings of the 12th International Conference on Mine Closure, Technical University Bergakademie Freiberg, Germany, pp. 633-644.

Results from the applied strategy of phytostabilisation on mining areas contaminated by heavy metals were presented. In our study area known as Guadiamar Green Corridor, where phytostabilisation have happened over 19 years, forestation has been found to improve soil fertility and microbial biomass, which is an indicator of improved soil quality. Moreover, different tree species have been found to affect soil chemistry and biology in different ways. White poplar was found to increase soil pH and to recover nutrients levels. However, stone pine was found to acidify the soil, increasing heavy metal availability and reducing microbial communities. In conclusion, previous to forestation is recommended to select the most suitable species for the specific conditions of the mining area to reclaim.

In this conference, Marta Gil-Martínez, predoctoral researcher from IRNAS-CSIC, had the opportunity to visit the Wismut Uranium Tailings Remediation Project , which started back in 1991 and currently clean-up, re-contouring and implementation of covers tasks are still in place. Last cover consists in revegetation to establish some forest and pastures areas, in order to maximize biodiversity.


Graduate Thesis on phytostabilization and soil organic matter

Trees planted in contaminated soils provide organic matter, contributing to a reduced mobility of contaminants and the process called “phytostabilization”.

Within the collaboration between IRNAS, CSIC and the University of Seville, Juan Fernando Montero supervised by the RESTECO researcher María T. Domínguez, has presented in July 2018, in the Faculty of Chemistry, the Graduate Thesis titled “Caracterizing fractions of organic carbon in forested soils after the Aznalcóllar mine accident (Guadiamar Green Corridor)”.

In this study, several fractions of soil organic carbon were analyzed, comparing sites under different tree species (white poplar, stone pine and wild olive). The study was repeated in two contrasted areas, with different soil acidity levels.

Using Fourier-transform infrared spectroscopy (FTIR), functional groups were caracterized in samples of soil and litter. The spectra of soil samples differed from those of litter, especially when the soil was neutral to basic, due to the higher intensity of microbial acitivity and litter decomposition in those sites.

Graduate Thesis about the Guadiamar

On Tuesday July 5th Margarita Ibáñez Ruiz del Portal presented her Graduate Thesis entitled “Temporal evolution of the system soil-plant in the Guadiamar Green Corridor, contaminated by trace elements after the Aznalcóllar mine spill: a bibliographic review (1998-2015)” (in Spanish), in the Technical School of Agronomical Engineer, University of Sevilla. The grade was “Outstanding” (10). Congratulations to Margarita, and to the Supervisors M.T. Domínguez and J.M. Murillo.

Summary (in Spanish) in Guadiamar Recare Hub