Quantifying Iron Concentration in Local and Synthetic Acid Mine Drainage: A New Technique Using Handheld Field Spectrometers; [Quantifizierung der Eisenkonzentration von synthetischer und in situ vorkommender saurer Bergbaudränage: Eine neue Technik unter Nutzung tragbarer Feldspektrometer]; [Cuantificando la concentración de hierro en drenajes ácidos de mina regionales y sintéticos: una nueva técnica usando espectrofotómetros de campo portátiles]

Pit lakes present a concern for public safety and environmental quality. With continuing advancement of imaging satellites, remote sensing spectroscopy may provide a useful tool for monitoring pit water quality across vast mining districts. Visible to shortwave infrared remote sensing has been widely used to monitor acid mine drainage (AMD) mineralogy at mine sites. However, few studies have examined the spectral signatures of mine-affected waters and open pit water bodies from a remote platform. The motivation for this study was to identify the spectral characteristics of AMD in a controlled laboratory setting in order to better interpret mine water bodies in remote sensing imagery. The spectral response of synthetic and local AMD were measured using a field spectrometer. Solutions with increasing Fe3+ and Fe2+ concentrations were mixed to mimic the chemical properties of local AMD. Synthetic solutions with known Fe concentrations were compared with local AMD for quantitative assessment. The spectral signatures of Fe3+ dominated waters possessed distinct characteristics that may be used for diagnostic identification. Specifically, the region between 0.35 and 0.625 µm was used to approximately quantify Fe3+ concentrations. Subtle changes in Fe concentrations in local AMD were identified using a field spectrometer alone. These findings suggest that subtle changes in open pit water quality may also be qualitatively and quantitatively measured by remote sensing spectroscopy. © 2016, Springer-Verlag Berlin Heidelberg.