Laboratory and airborne reflectance spectroscopic analyses of lignite overburden dumps

• Published in: Journal of geochemical exploration 1998-11, Vol.64 (1), p.47-65
• Main Authors: Krüger, G., Erzinger, J., Kaufmann, H.
• Format: Article
• Language: English
• Subjects: Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Exact sciences and technology; hyperspectral; imaging spectrometry; lignite mining; mineralogical composition; overburden dumps; Pollution, environment geology; quantitative analysis; reflectance spectroscopy
• ISSN: 0375-6742; 1879-1689
• DOI: 10.1016/S0375-6742(98)00020-X

Visible and infrared reflectance spectroscopy is used for a mineralogical–chemical analysis of open pit lignite mine overburden dumps. Quantitative determinations of kaolinite, organic carbon, and pyrite contents based on their distinct diffuse spectral reflectance properties are presented. Spatial compositional information of the dumps is of great importance for the study of geochemical alteration and its hydrogeological effects, as well as for the definition of the most suitable recultivation goals. The analysis of kaolinite, organic carbon, and pyrite contents in a spatial context is relevant to the remediation of the mines as these parameters are related to problems like slope instability, plant regrowth, and acid mine drainage. The study area is located in the Central German Lignite Mining District and includes the two open pits of Zwenkau (active) and Espenhain (abandoned). Different spectrometric means are applied, including laboratory and field spectroscopy, as well as imaging spectroscopy based on airborne hyperspectral data of the Digital Airborne Imaging Spectrometer (DAIS 7915; Chang et al., 1993). The spectral analyses have been carried out for (a) the dumps in the field, (b) field samples in the laboratory, and (c) mixture series of field samples and mineral standards. Chemical and mineralogical analyses of the field samples served as references and were successfully correlated to absorption features of laboratory reflectance spectra. Based on the relative absorption depth, kaolinite contents were derived with an accuracy of about 2% by weight for the low contents present in the dumps (