Browsing by Subject "Tailings"

Now showing 1 - 7 of 7
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    Chemistry, Mineralogy & Liberation Characteristics of Samples of EVTAC Concentrator Unit Operations
    (University of Minnesota Duluth, 2005) Niles, Harlan B
    Minnesota taconite operations frequently encounter quality problems due to chemical-mineralogical variations in crude ore blends. Mine personnel have expressed interest in determining ore blend behaviors in unit operations of concentrators. This knowledge could assist in providing ore blends that produce more uniform and desirable final concentrates. The behavior of ores in intermediate concentrator stages may also help concentrator operators to adjust units to produce optimum results. A project proposal submitted to the Permanent University Trust Fund (PUTF) to determine chemistry, mineralogy, and indicated magnetite liberation for samples of unit operations of two EVTAC ore blends was approved. Feed, concentrate, and tailing samples from concentrator unit operations that represented two crude ore blends were received by the Coleraine Minerals Research Laboratory (CMRL) in 2001 and 2002. They were designated Set 1 and Set 2, respectively. The samples were dried, mixed, and split into portions for "As Is" Davis tube magnetic separations and other splits to be pulverized for chemical analyses and for x-ray diffraction. Chemistry was run at the CMRL and x-ray diffraction patterns were run at the University of Minnesota Shepherd Laboratory in Minneapolis. Mineral percentages in each sample were calculated from the chemical analyses on a spreadsheet in a "Quattro Pro for Windows" computer program after examining x-ray patterns to determine the minerals that were present. The spreadsheet was adjusted to comprehend minerals present and their chemical compositions, and so that the sum of mineral percentages in a sample was within 0.50 percent of the chemistry total oxides (near 100 percent). The results of “As Is" Davis tube separations are given in Table I. It shows magnetic weight recoveries and concentrate iron and silica percentages and provides an indication of the progressively improved magnetite liberation through the concentrator operations. It also shows that liberation in sample Set 2 was somewhat better than in Set 1, and, when compared to the sample chemical analyses in Table 2, separation efficiencies in concentrator units are demonstrated. Calculated mineral percentages in cobber feed samples showed that total silicates were nearly equal in Sets 1 and 2, that the hematite percentage was considerably higher in Set 1, and that total carbonate was higher in Set 2. In the final concentrates, most hematite and silicates had been rejected from both sets, but the total carbonate from Set 2 was 3.6 percent, about double that for Set 1. A set of bar graphs was made for each unit operation, which shows percentages of each mineral in the feed, concentrate and tailing. They illustrate the recovery and rejection of each mineral in each concentrator operation. Company personnel may therefore distinguish the effectiveness of each unit in recovering and rejecting particular gangue minerals.
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    Control of Residual Sulfides in Flotation Tailings of Cu-Ni Duluth Complex via Grinding Media Selection
    (University of Minnesota Duluth, 2001) Iwasaki, Iwao
    The effects of grinding media chemistries on ball wear and flotation were compared by grinding a Cu-Ni bearing Duluth Complex sample using forged steel and 27% Cr cast iron balls under nitrogen, air and oxygen atmospheres. Both types of balls increased their wear in air and oxygen atmospheres, but Cr balls wore only one-third as much as forged steel balls. The wear increased roughly in proportion to the oxygen content of the mill atmosphere. Flotation recoveries of sulfide minerals were adversely affected when the sample was ground in a nitrogen atmosphere. Residual sulfur in flotation tailings ground using both types of grinding balls under an air or oxygen atmosphere was lowered to about 0.15%, with Cr balls producing somewhat lower sulfur values. Davis magnetic tube tests on flotation tailings lowered the residual sulfur to 0. 1 % or less by recovering mainly pyrrhotite. PGM recoveries paralleled the recoveries of sulfur, although Pd recoveries remained somewhat lower, implying that a part of Pd might be associated with pyrrhotite. Pd, not recovered in flotation, appeared to be recovered by magnetic separation of flotation tailings.
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    Documenting the Historical Use of Taconite Byproducts as Construction Aggregates in Minnesota – A GIS-based Compilation of Applications, Locations, Test Data, and Related Construction Information
    (University of Minnesota Duluth, 2007) Oreskovich, Julie A; Patelke, Marsha Meinders; Zanko, Lawrence M
    Aggregate shortages are causing increasing concern for population centers across the country. Meanwhile, Minnesota’s taconite mining industry generates over 125 million tons of mining and processing byproducts annually that hold aggregate potential of traprock quality. Materials such as blast rock, coarse crushed rock, and coarse tailings (collectively known as Mesabi Hard Rock™) have been staples of northeastern Minnesota road construction for over four decades. Infrastructure is already in place to move these materials to markets throughout the country to augment local aggregate resources. Because these highway construction applications are not widely known outside of northeastern Minnesota, this study was undertaken to: 1) document how and where taconite byproducts have been used; and 2) assemble related test data. Letters, interviews, site visits, and searches of archived records were the primary modes of data collection. The product is a project report with a stand-alone Microsoft Access (or Excel) database and an ArcView GIS product containing mappable Mesabi Hard Rock™ usage locations with accompanying data. Topics that users can query include byproduct type, location, application, date, authority, and contact person. With such information, users can determine the applicability of this resource to their own projects.
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    Duluth Complex Mineral Separations
    (University of Minnesota Duluth, 2001) Niles, Harlan B
    The Minerals Division of the Minnesota Department of Natural Resources (DNR) is examining leaching characteristics of minerals that would likely be present in tailing produced by mining and concentrating copper- and nickel sulfide-bearing ores from the Duluth Complex. The Coleraine Minerals Research Laboratory (CMRL) of the Natural Resources Research Institute submitted a project proposal to provide concentrates of silicate minerals for DNR leaching studies. The DNR accepted the proposal and funded the project for $14,210.
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    The Economics and Logistics of Transporting Taconite Mining and Processing Byproducts (Aggregate): Minnesota and Beyond
    (University of Minnesota Duluth, 2008) Zanko, Lawrence M; Ogard, Elizabeth E; Stewart, Richard D
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    Performance of Taconite Aggregates in Thin Lift HMA: Final Report - January 31, 2012
    (University of Minnesota Duluth, 2012) Zanko, Lawrence M; Johnson, Ed; Marasteanu, Mihai; Patelke, Marsha Meinders; Linell, David; Moon, Ki Hoon; Oreskovich, Julie A; Betts, Ray; Nadeau, Lynette; Johanneck, Luke; Turos, Mugur; DeRocher, Will
    This project was undertaken to advance the knowledge of the beneficial uses of taconite mining coarse tailings (taconite fine aggregate) for thin lift hot mix asphalt (HMA), to facilitate technical information gathering and marketing of such uses and properties, and to encourage the beneficial use of recycled/byproduct materials like durable and wear- and skid-resistant taconite (Mesabi) aggregates, recycled asphalt pavement (RAP), and asphalt shingles. In combination, the use of each is highly desirable because it promotes resource conservation, safety, and energy-saving. Outcomes of this study suggest that Mesabi rock and tailings products show promise as components of 4.75-mm Dense-graded, Stone Matrix Asphalt, and Ultra-Thin Bonded Wearing asphalt mixtures. Laboratory and field investigations of taconite tailings should continue. The Mesabi rock can be incorporated in standard Superpave, SMA, and fine/sand asphalt mixtures in upcoming construction projects. In each case construction and long term field performance should be evaluated. The investigators conclude that taconite-based thin lift HMA mixes that also incorporate RAP should be recognized as an environmentally sound, i.e., combining the use of byproduct and recycled/reclaimed materials, and high-quality option for HMA pavement rehabilitation and preservation. Collectively, the material testing results suggest that thinner wear-course pavements made from appropriately designed taconite-based mixes can match or exceed the service life of conventional MnDOT Level 4 mixtures. If extended service life is realized, then taconite fine aggregate could be a cost-effective choice at end-user locations where high-quality local aggregate sources are lacking or absent. These enhanced performance attributes can add intrinsic value to taconite materials and make them more desirable to use and more cost-effective to transport longer distances, thereby improving and broadening their near- and long-term potential for regional and national highway infrastructure projects.
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    Properties and Aggregate Potential of Coarse Taconite Tailings from Five Minnesota Taconite Operations
    (University of Minnesota Duluth, 2003-12) Zanko, Lawrence M; Niles, Harlan B; Oreskovich, Julie A