Leaching Behavior of Metals from Taconite Tailings as an Embankment Fill Material

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Schreck, Sam
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Honors Projects and Posters
University Honors Program

The Honors project is potentially the most valuable component of an Honors education. Typically Honors students choose to do their projects in their area of study, but some will pick a topic of interest unrelated to their major.

The Honors Program requires that the project be presented at a poster presentation event. Poster presentations are held each semester. Most students present during their senior year, but may do so earlier if their honors project has been completed.

This site presents project descriptions and selected posters for Honors projects completed since the Fall 2015 semester.

Civil, Construction, and Environmental Engineering

Taconite tailings are the ore-bearing, by-product rocks of iron mining, predominantly consisting of silicate and fine magnetite crystals. In recent years, the use of taconite tailings in pavement construction has increased considerably due to their superior mechanical properties. However, an environmental impact assessment of taconite tailings is required before their potential use in construction purposes. Taconite tailings may leach heavy and toxic metals, which could contaminate the soil, surface, and groundwater. Coarse, sand, fine, and composite sized taconite tailings were subjected to pH-dependent leaching tests in the pH range of 2 to 13 to investigate the leaching behavior of aluminum (Al), chromium (Cr), magnesium (Mg), and sulfate (SO4). In addition, Toxic Characteristic Leaching Procedure (TCLP), Synthetic Precipitation Leaching Procedure (SPLP), Water Leach Test (WLT), and U.S. Geological Survey leach test (USGS) were performed to evaluate the leaching behavior of taconite tailings in different environmental conditions. The test results show the highest concentrations of metals were leached from fine sized taconite, whereas the lowest amount of metal concentrations were leached from coarse sized taconite tailings. Magnesium and sulfate demonstrate a cationic leaching pattern, and aluminum and chromium indicate an amphoteric leaching pattern. Taconite tailings leached the highest metal concentrations in TCLP effluent; therefore, it is recommended as the most conservative test procedure to evaluate the leaching of these metals from taconite tailings.