Browsing by Subject "Minnesota's Mesabi Iron Range"

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    Historical Use of Taconite Byproducts as Construction Aggregate Materials in Minnesota: A Progress Report
    (University of Minnesota Duluth, 2006-10) Oreskovich, Julie A; Patelke, Marsha Meinders
    Coarse taconite tailings and crushed taconite rock (Mesabi Hard Rock™) have been a staple of the road construction industry on Minnesota’s Mesabi Iron Range for over four decades. Comparable to trap rock in quality, taconite aggregates have proven to be strong and durable when used as subgrade and base material and in bituminous pavements. The superior hardness and durability of these materials make them a viable candidate for exporting to the Twin Cities metro and out-state areas and to surrounding states as stand alone aggregate or for blending with local aggregates to produce more competent pavements. Documenting how and where taconite byproducts have been used in Minnesota, along with related test and longevity data, will provide the potential end user a basis for selecting these materials over another aggregate source.
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    Process Development and Evaluation of Cook Area Glacial Lake Clays for Cat Litter
    (University of Minnesota Duluth, 1996-01) Oreskovich, Julie A
    Clumpable cat litters are commanding an increasing share of the cat litter market. Produced from sodium bentonite, a swelling clay, clumpable litters absorb and bind up cat urine, restricting its penetration to a shallow depth. The resultant "clump" is easily removed, leaving the remaining litter fresh. Bentonite is the same clay used as a binder in the production of taconite pellets on Minnesota's Mesabi Iron Range. It is shipped by rail from Wyoming, adding significantly to cost per ton of pellets. Past research has shown that the glacial lake clays from the Cook, Minnesota, area can be used wholly or in part as a taconite pellet binder. Recent testing has demonstrated the clumpability of these same clays, making them a potential local source for clumpable cat litter. Further investigation of the Cook area clays could spawn development of a cat litter industry for northeastern Minnesota. Such a development may in turn prompt Minnesota's taconite industry to take a new look at using local clays as a pellet binder in its continual pursuit of cost reduction.
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    SEM Image Comparison of Selected Crushed Mineral Standards Sample Preparation and Analysis
    (University of Minnesota Duluth, 2010-09) Schreiber, Megan
    The qualitative investigation observed, through scanning electron microscope (SEM) analysis, the morphological (size and shape) characteristics that specimen-grade mineral standards can exhibit on a microscopic scale following mechanical crushing. A hand-crushing technique (via mortar and pestle) was used to represent the macroscopic mineral crushing that occurs throughout the taconite mining industry. The results are intended to show how SEM analyses of these crushed standards can be used as a point of reference for comparison to crushed minerals found within the taconite ore and taconite mining by-products of Minnesota’s Mesabi Iron Range. For this SEM-based investigation, standards were chosen as analogs to three common minerals found on the western Mesabi Iron Range: quartz, magnetite, and stilpnomelane. A fourth mineral standard (actinolite) was chosen as an amphibole mineral that can occur in the contact-metamorphosed easternmost portion of the Mesabi Iron Range. The findings show that mechanical crushing can generate elongated mineral particles (EMP) from all four standards, including quartz. Simply put, an EMP is a particle having length-to-width ratio ≥3:1. Consequently, most – if not all – mineral processing and/or rock crushing operations nationwide have the potential to generate elongated mineral particles.