Using airborne hyperspectral data to characterize the surface pH of pyrite mine tailings

High spatial-resolution Hymap airborne hyperspectral data was used to generate predictive pH maps of acid mine drainage (AMD) for the Sotiel-Migollas mine complex, Southwest Spain. These maps portray the spatial distribution of highly acidic areas, which are likely associated with high concentrations of heavy metals. A predictive pH model was built using partial least squares (PLS) analysis to determine the relationship between the spectral response of AMD samples and their leachate pH measured in the laboratory. A validation of the model for an independent data set shows a r² of 0.71 between actual and predicted pH values. Hyperspectral imagery is shown to provide an effective means to quantitatively pinpoint sources of acidity.