MAPPING THE DISTRIBUTION OF MINE TAILINGS IN THE COEUR-DALENE RIVER VALLEY, IDAHO, THROUGH THE USE OF A CONSTRAINED ENERGY MINIMIZATION TECHNIQUE

Ferruginous fluvial sediments deposited on the banks and on the floodp lain of the Coeur d'Alene River in northern Idaho have been contaminat ed by trace metals released by mining activities in and around the tow n of Kellogg, Idaho. These ferruginous sediments are amenable to detec tion and mapping by remotely sensed data. Data collected by the Airbor ne Visible/Infrared Imaging Spectrometer (AVIRIS) were analyzed both t o map exposed concentrations of these sediments and also to consider t heir mineralogic variability. The processing tool used to map the ferr uginous sediments was the recently developed constrained energy minimi zation (CEM) technique, which on a pixel-by-pixel basis maximizes the response of the target signature and suppresses the response of undesi red background signatures. CEM abundance images, produced using both l aboratory and image data as the target signatures, were thresholded to produce a set of spectra dominated by the ferruginous sediment spectr al response. Spectral subsections of this data set were analyzed using principal components analysis, and endmember image spectra representi ng, in most cases, known mineral phases were identified. (C) Elsevier Science Inc., 1997