This spectacular hyperspectral image was produced using the CASI visible/near infrared sensor. It emphasizes the high volumes of iron present at the Bauer Site, and also clearly demonstrates eolian redistribution of the tailings. Tailings near the mill appear as blue and dark blue; they contain high concentrations of sulfides (especially the darkest blue areas). The yellow is a clay crust, which is mixed with sparse vegetation (browner areas). Note the second tailings area to the West, where tailings have breached from the main area near the mill, and have been subsequently carried northward by wind action (the distinctive dune pattern in the upper left of the image). These eolian fines may be carrying toxic metals into the local drainage.

Assessment of classic non-smelter mill site - Characteristics of tailings
a) In situ material
b) eolian tailings
Downwind distribution and potential impact

Bauer is an abandoned mine mill-site southwest of Salt Lake City, at the base of the Oquirrh mountains. Bauer was a waste repository for various local mining districts (notably the nearby Stockton District). The site is of interest because of a high concentration of sulphides (mainly pyrite and galena) in the tailings. Gangue minerals are quartz and calcite. The tailings therefore carry large amounts of iron, arsenic, lead and zinc.

Iron occurs in such high concentrations that a major portion of the surface of the tailings pond near the mill is covered with oxidizing iron crusts (ferricrete, pictured beside).

This case study is part of a NASA-sponsored project, evaluating hyperspectral remote sensing techniques as applied to mine waste characterization. It is also part of the EPA Region 8 AML (Abandoned Mine Lands) Project.