Mapping the distribution of mine tailings in the Coeur dʹAlene River Valley, Idaho, through the use of a constrained energy minimization technique

Ferruginous fluvial sediments deposited on the banks and on the floodplain of the Coeur dʹAlene River in northern Idaho have been contaminated by trace metals released by mining activities in and around the town of Kellogg, Idaho. These ferruginous sediments are amenable to detection and mapping by remotely sensed data. Data collected by the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) were analyzed both to map exposed concentrations of these sediments and also to consider their mineralogic variability. The processing tool used to map the ferruginous sediments was the recently developed constrained energy minimization (CEM) technique, which on a pixel-by-pixel basis maximizes the response of the target signature and suppresses the response of undesired background signatures. CEM abundance images, produced using both laboratory and image data as the target signatures, were thresholded to produce a set of spectra dominated by the ferruginous sediment spectral response. Spectral subsections of this data set were analyzed using principal components analysis, and endmember image spectra representing, in most cases, known mineral phases were identified.