Mapping hazardous low-pH material in mining environment: Multispectral and hyperspectral aproaches

The pH is one of the major chemical parameter affecting results of remediation programs carried on abandoned mines and dumps and one of the major parameters controlling heavy metal mobilization and speciation. Two approaches that contribute to pH mapping were compared. Firstly, high-altitude spectroradiometry (ASTER - Advanced Spaceborne Thermal Emission and Reflection Radiometer satellite data) together with ground-based spectroradiometry (ASD Filedspec spectroradiometer) were employed in order to identify the locations of the most significant sources of AMD discharge at the Sokolov lignite open-pit mines, Czech Republic. As a result, a map with delineated low-pH zones was created. Secondly, the feasibility of mapping surface pH on the basis of airborne multi-flight-line HyMap hyperspectral (HS) datasets was tested. The geochemical and mineral property was linked with emissivity spectra acquired in the field and laboratory. The spectral property of both AMD indicating minerals and the organic component occurring as part of mixtures proved to be identified using spectroscopy and spectral feature fitting (SFF) technique was employed to map the defined endmembers indicating a certain pH ranges in the HS image datasets.