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Physical Sciences and Mathematics Commons

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Geology

Minnesota State University, Mankato

Minnesota

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Full-Text Articles in Physical Sciences and Mathematics

Fluid Properties In The Formation Of High-Grade Iron Ore In Northern Minnesota, Elizabeth Drommerhausen Aug 2014

Fluid Properties In The Formation Of High-Grade Iron Ore In Northern Minnesota, Elizabeth Drommerhausen

Journal of Undergraduate Research at Minnesota State University, Mankato

The Mesabi Iron Range in Northern Minnesota has been a major producer of iron ore for over 100 years. Production has been from the 1.85 – billion-year –old Biwabik Iron Formation, an iron-rich sedimentary rock that is tilted gently to the south. Most of the known high-grade ore lies near the surface and has been already mined. Determining whether more high-grade ore may lie at depth could have significant economic impact on the mining industry in northern Minnesota. To evaluate the likelihood of finding more high-grade iron ore deeper underground, it is important to determine the source of the fluids …


Silica Distribution In Oxidized Biwabik Iron Formation: Ore-Waste Cutoff Prediction, Ryan Rague Aug 2014

Silica Distribution In Oxidized Biwabik Iron Formation: Ore-Waste Cutoff Prediction, Ryan Rague

Journal of Undergraduate Research at Minnesota State University, Mankato

Oxidation of iron formation in the Mesabi Iron Range, Minnesota, has negatively impacted recovery of the main ore mineral, magnetite, by two mechanisms. First, magnetite has been partially or completely oxidized to hematite (martite), which is not magnetically separable. Second, silica has been remobilized during the oxidation process, and comprises a higher percentage of the ore concentrate than is desirable due to its altered grain size, making it difficult to grind sufficiently. Fluid inclusion data showed that fault-channeled, diagenesis-stage fluids (mean T homog = 154° C; mean salinity = 9.5 wt% NaCl equivalent) were responsible for early oxidation of iron …