Resíduos de exploração de carvão: avaliação, monitorização e recuperação de impactos ambientais através de deteção remota e análise geoestatística
- Universidade do Porto(líder)
- Universidade de Évora(parceiro)
A autocombustão de carvão pode ocorrer em camadas aflorantes, durante as atividades de exploração mineira, durante o armazenamento e transporte de carvão e em depósitos de resíduos resultantes da exploração. A autocombustão de carvão causa a mobilização de grandes quantidades de poluentes, matéria particulada, compostos orgânicos e elementos tóxicos, que podem ser emitidos, libertados ou lixiviados, para os solos, águas e atmosfera do ambiente envolvente. A atividade mineira na Bacia Carbonífera do Douro causou impactes no ambiente por causa, entre outros, da autocombustão de três escombreiras, cuja ignição foi causada por incêndios florestais que ocorreram em 2005. A caracterização dos materiais que constituem estas escombreiras em autocombustão, que é fundamental para a identificação potenciais impactos sobre o ambiente, foi desenvolvida em trabalhos anteriores. O principal objetivo deste projeto é a caraterização e quantificação dos impactes ambientais causados pela autocombustão da escombreira de S. Pedro da Cova, incluindo os impactes nos ecossistemas e saúde humana, uma vez que a mesma se localiza perto de um centro habitacional e infraestruturas sociais. A investigação dos solos e águas da área envolvente à escombreira de S. Pedro da Cova permitirá a identificação dos compostos orgânicos e elementos inorgânicos que podem ser perigosos para os ecossistemas e saúde humana. A composição geoquímica dos solos e águas colhidos na área envolvente à escombreira será determinada, e as temperaturas associadas à autocombustão e movimentos de material na escombreira serão monitorizados através de técnicas de deteção remota. A quantificação de poluentes nos solos é águas permitirá a análise da sua distribuição espacial e a extensão da poluição através da aplicação de algoritmos geoestatísticos e da exploração dos dados geoespaciais que permitirão a caracterização dos riscos ambientais e de saúde. A interpretação e integração dos resultados permitirá a identificação e caraterização dos impactes ambientais causados pela escombreira em autocombustão, que serão essenciais para a definição de medidas apropriadas de mitigação e recuperação. Espera-se com a disseminação dos resultados contribuir para o conhecimento científico e fornecer informações importantes para os tomadores de decisões sobre a mitigação e recuperação dos impactes ambientais.
Objetivos, atividades e resultados esperados/atingidos
The self-burning of coal wastes piles resulted from coal mining activities represent a source of pollutants that are emitted, released or leached to the surrounding environment. During the combustion process, the emission of harmful gases and particulate matter into the atmosphere, the mobilization and leaching of hazardous elements may affect the atmosphere, soils, surface and groundwater, and consequently may cause environmental pollution and effects on biodiversity and human health. Considering the above and the fact that the impacts on surrounding environment and human health caused by self-burning coal waste piles in Douro Coalfield were never investigated, the main objective of this project proposal is to identify and characterize the environmental impacts arising from the self-burning process in S. Pedro da Cova waste pile (under self-combustion process since 2005 until present days and located near a population centre and social infrastructures) in order to identify the proper mitigation or reclamation measures to solve the environmental and human-health issues. For that, the specific objectives are: i) to compile and systematize information about the constituents of coal waste material that may be release to the surrounding environment, principally as a consequence of the self-combustion process; ii) to identify and quantify hazardous elements in soils, and water from streams, springs and wells in the surrounding area of S. Pedro da Cova waste pile through geochemical analyses; iii) to monitor combustion temperature and mass movements in the coal waste pile through remote sensing using unmanned aerial vehicles. iv) to improve the GIS open source application in order to produce the required cartography to quantitatively describe the spatial distribution of the contaminated areas through the quantification of pollutants and analysis of pollution extent using spatial analysis and geostatistical algorithms improving the estimation of the exposure factors in the limited area and characterizing the environmental and health risks exploiting the derived geospatial data; v) to compare the obtained results for concentration of pollutants in soils and water in the surrounding area of S. Pedro da Cova waste pile with values from legislation and other investigated case studies from the literature; vi) to predict evolutive scenarios of the self-combustion and identify appropriated measures for mitigation or reclamation of environmental impacts (the treatment and reutilization of mining waste should be considered)
1. Systematization of information and sampling design
2. Soils sampling and analysis
3. Waters sampling and analysis
4. Remote sensing monitoring of combustion temperature and mass movements
5. Geostatistical analysis
6. Integration of the results
The evaluation and monitoring of combustion temperature, mass movements within the coal waste pile and gaseous emissions will be attained through remote sensing using unmanned aerial vehicles. Drones will be used for collection of data with photographic cameras and other sensors that will provide information for environmental assessments. The results will provide information about mass movements associated with instabilities caused by the combustion process, as well as the temperature in the surface of the coal waste pile. The results from geochemical composition of soils and water samples, together with the data collected with UAV will be used as input data in the GIS open source application in order to create maps with the hazard chemical elements concentration, temperature variations and risk maps. Other type of geographic information such as Digital Elevation Models (DEM), Normalized Difference Vegetation Index (NDVI), Land Change, Land Use Land Cover (LULC), forest fire risk, groundwater vulnerability to pollution and soil erosion will also be created and integrated in the application. Statistical analysis will also be performed in the same application providing useful outputs to consider in the decision support tool such as histograms, plots and variograms. The GIS open source application will allow the monitoring of several parameters such as elements of concentration, the dynamics of the temperature and combustion process at specific periods of time, gaseous emission, mass movements through the creation of maps representing the spatial and temporal variations
The resulting plots can be very useful to analyze and evaluate the behavior of the combustion process at specific points, helping to establish prevention measures. The improved application will incorporate a deeper geostatistical analysis through several functionalities created. The spatial analysis will be evaluated through the maps returned by the application. The project implementation will include bibliographic research about the theme in general and about the self-burning coal waste piles from Douro Coalfield in order to proceed with the systematization of the information about the components of the coal waste material (including also the leachates resulting from water percolation through those materials and by-products resulting from the combustion process), that may be release to soils, water and air of surrounding area. This systematization is very important to identify potential problematic elements (e.g., presence of toxic elements, elements with high concentrations). The knowledge about the chemical composition of the solid materials and leachates that constitutes the coal waste piles together with the analyses of soils and waters collected nearby but not influenced by the coal waste piles are essential for the identification of pollutants elements and their extent. For that, samples of the referred materials not influenced by the coal waste piles will also be collected and analysed, and data from previous research about the chemical composition of coal waste materials will be considered. The results obtained through the different methodologies will be therefore treated, analyzed and integrated, which will allow the characterization of soils, waters and air of the surrounding area of the S. Pedro da Cova waste pile and, consequently, and the identification of inorganic and organic elements that can be hazardous. The characterization of environmental impacts associated with the coal deposit will allow the identification of proper mitigation or reclamation measures for the resolution of environmental and human health issues. The results will also allow the analysis of the dynamics of the combustion process in the coal waste pile as well as predict evolution scenarios. The studies related with the phenomenon of self-burning coal waste piles can provide a valuable service to the local communities, supplying information about the concentration of toxic elements that are being release to environment, about the hazard of exposure to potentially harmful emissions, and about the appropriated mitigation or reclamation measures that should be develop to solve the environmental and human health issues.