Page 4 - MN 2020 Conference Program

PROCESSING ENVIRONMENTAL

Chair: Wiegou Xie; University of Minnesota Duluth, Chair: Joel Asp; SEH, St. Cloud, MN
Duluth, MN
3:00pm
12:30pm From Mining to Mainstream: Mitigation for Transportation
Potential Aplplications for Dry Beneficiation of Iron Ore Fines Corridors
Using a TRIBO-Electrostatic Belt Separator Kevin Eisen; Barr Engineering Co., Minneapolis, MN, Mehgan Blair;
Lucas Rojas-Mendoza, Kyle Flynn, Frank Hrach, and Abhishek Gupta; Barr Engineering Co., Duluth, MN and Denise Levitan, Stephanie Theriault
ST Equipment & Technology, Needham, MA and Ward Swanson; Barr Engineering Co, Minneapolis, MN
ST Equipment & Technology (STET) tribo-electrostatic separator allows for Thorough characterization of host deposits of potentially acid-generating
the beneficiation of fine powders with an entirely dry technology. The STET materials is imperative to developing proper management protocols. Al-
separator is suited for separation of very fine (<1µm) to moderately coarse though acid-generating material is often associated with mining-related ac-
(500µm) particles. STET has successfully beneficiated iron ore samples tivities, transportation corridors may intersect sulfide-bearing deposits that
including run-of-mine ores, tailings and itabirite and experimental findings also require characterization and management. The Minnesota Department
indicate that low-grade ores can be upgraded to commercial grades (58- of Transportation, along with Barr Engineering Co. and the Natural Resources
62% Fe) while simultaneously rejecting silica. A compendium of experimen- Research Institute, recently developed a manual for transportation projects
tal results and high-level flowsheets and economic evaluations for selected to evaluate and manage rock and borrow sources. Specifically, the manual
applications are presented. Challenges associated to the adoption of the describes the process of screening, characterizing, evaluating, and mitigat-
technology and a comparison to available technologies are also discussed. ing materials that may be acid generating, as well as providing an outline for
environmental monitoring.
1:00pm
Innovative Two-Mass Screen Technology Meets the Demand 3:30pm
for Larger Higher Throughput Screens On the Road Again: Mitigation and Monitoring Following
Edward Wipf; Voestalpine, Portland, TX Construction of an In-Road PAG Rock Repository
The General Kinematics Two-Mass Screen technology is gaining global Mehgan Blair; Barr Engineering Co., Duluth, MN and Jason Richter;
Minnesota Department of Transportation, Maplewood, MN
momentum in the Mining Industry. The STM-SERIES™ Two-Mass Vibratory
Screens are high throughput screens that, in the same footprint as an ex- Reconstruction of Hwy169 from Tower-Ely cut through significant exposures
isting brute force banana screen, on an equal comparison basis, claim to of potentially acid-generating (PAG) rock. Implementation of a mitigation plan
handle up to a 30% - 40% throughput increase, with the same or better during construction resulted in a design that minimized fragmentation, ex-
efficiency. General Kinematics STM-SCREEN™ screens utilize GK’s prov- posure and oxidation, and leaching of PAG rock. Site limitations included a
en Two-Mass, natural frequency drive design, which consumes much less narrow working corridor, blasting/rock placement schedules, and equipment
energy to do this more significant task, to be inherently more reliable and capabilities. Site-specific amendment, mixing/blending techniques, and
offer a longer service life for the cost of ownership. General Kinematics’ screening methods were developed to achieve the mitigation design criteria.
unique technology and the solutions it offers to the mining industry will be Subsequent to cover placement, post-construction groundwater monitoring
discussed in detail with case study examples of these larger higher through- detected a drain-down response and rebound in adjacent groundwater qual-
put screens. ity due to unusually wet conditions. Ongoing groundwater sampling and site
inspection is anticipated for 5-10 years.
1:30pm
Characterizing Carbon Formation in a MIDREX Direct 4:00pm
Reduction Process Innovative Pavement Repair with Taconite and Microwave
Michelle Godoy; Colorado School of Mines, Lakewood, CO and Technology
Emmanuel De Moor, Christopher Harris,Wolfgang Sterrer and Lawrence Zanko and Sara Post; UMD Natural Resources Research
Victor Romor; Voestalpine, Portland, TX Institute, University of Minnesota Duluth, Duluth, MN
An alternative to traditional Blast Furnace (BF) iron ore reduction is the Elec- Since the mid-2000s, the Natural Resources Research Institute at the Uni-
tric Arc Furnace (EAF) scrap re-melting. Recycled steel scrap contains im- versity of Minnesota Duluth has performed research on the integration of iron
purities such as copper which can be reduced by charging Direct Reduction ore (taconite) mining materials and mineral byproducts into pavement repair
Iron (DRI) in EAFs. Improved thermal efficiency of EAFs are claimed to be technologies, focusing on how they fit into a sustainable pavement infra-
achieved with high carbon DRI. Carbon formation in DRI and Hot Briquet- structure. Today’s presentation describes that effort and summarizes recent
ted Iron (HBI) produced in voestalpine’s MIDREX plant was investigated with and ongoing research related to: 1) a rapid-setting pavement patching mix
analysis of reaction thermodynamics and kinetics. X-ray diffraction, Moss- made with taconite tails and other mineral-based components and 2) poten-
bauer spectroscopy and Leco Carbon\Sulfur analysis were used to deter- tial microwave technology applications. Laboratory testing and the outcome
mine carbon content. of field trials conducted between 2016 and 2019 at multiple locations and in
various pavement types are highlighted.

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