Iron-ore tailings secondary resource
Iron-ore tailings are processing-derived residual feeds from iron-ore production, distinct from natural iron ore, elemental iron and individual iron minerals. This record curates a mixed goethite/hematite/quartz tailing used as a source of biologically mobilized iron in a laboratory two-stage manganese-leaching experiment. The unnamed facility and tested composition do not define all iron-ore tailings. No criticality designation is inherited from constituents.
Microbial & Biochemical Mechanisms (1)
Mixed-culture iron mobilization from tailings for downstream manganese leaching
bioleaching
Microbial
An anaerobic mixed-culture iron-tailings stage supplied Fe(II)-bearing liquor to a separate manganese-ore stage. The experiment supports iron mobilization from the mixed tailings in this culture system, consistent with the proposed reductive role of its dissolved iron. It does not quantify a particular organism or mineral phase contribution, or isolate a recovered iron product.
Experimental Context & Analytical Limits:
Living mixed metal-reducing cultures originated from a fen in Houghton County, Michigan, and previously adapted cultures inoculated the iron stage. No individual strain or causal community member is resolved here. Fermented Typha latifolia biomass plus 5 g/L sucrose supplied organic nutrient liquid. Methods 2.4 and Figure 5 describe two 250 mL Buechner flasks in series: the drawing labels 200 g iron feed and 350 g manganese ore. Methods 2.1 identifies the iron feed as tailings from an unnamed iron-ore production facility, smaller than 0.15 mm; the manganese ore came from an abandoned Keweenaw County mine and was crushed below 3 mm. After seven days of adaptation, 300 mL fresh nutrient per week was supplied in five 60 mL increments. Packed beds, fermentation locks and a submerged manganese-flask outlet were used to maintain anaerobic conditions. Experiments were run in triplicate. A numerical flask incubation temperature is not specified in these methods; Section 3.6 discusses ambient-temperature operation. Reported operating pH was 4.7 +/- 0.7 in the iron stage and 4.4 +/- 0.8 in the manganese stage. Overflow Mn was measured by colorimetric periodate oxidation and Fe(II) by 1,10-phenanthroline spectrophotometry; filtration and operational dissolved-fraction details are not supplied. These assays do not resolve the mineral phase contributing each metal.
Living mixed metal-reducing cultures originated from a fen in Houghton County, Michigan, and previously adapted cultures inoculated the iron stage. No individual strain or causal community member is resolved here. Fermented Typha latifolia biomass plus 5 g/L sucrose supplied organic nutrient liquid. Methods 2.4 and Figure 5 describe two 250 mL Buechner flasks in series: the drawing labels 200 g iron feed and 350 g manganese ore. Methods 2.1 identifies the iron feed as tailings from an unnamed iron-ore production facility, smaller than 0.15 mm; the manganese ore came from an abandoned Keweenaw County mine and was crushed below 3 mm. After seven days of adaptation, 300 mL fresh nutrient per week was supplied in five 60 mL increments. Packed beds, fermentation locks and a submerged manganese-flask outlet were used to maintain anaerobic conditions. Experiments were run in triplicate. A numerical flask incubation temperature is not specified in these methods; Section 3.6 discusses ambient-temperature operation. Reported operating pH was 4.7 +/- 0.7 in the iron stage and 4.4 +/- 0.8 in the manganese stage. Overflow Mn was measured by colorimetric periodate oxidation and Fe(II) by 1,10-phenanthroline spectrophotometry; filtration and operational dissolved-fraction details are not supplied. These assays do not resolve the mineral phase contributing each metal.
Curated Evidence Points:
Support
Source:
borkar2026
Methods 2.1 and Tables 3–4 identify the tailings and report XRD phase proportions of 19.3 wt% goethite, 5.9% hematite and 74.8% quartz. The reported 16 wt% Fe is calculated from XRD, not an independent bulk chemical assay. Figure 5 labels the flask solid as 200 g iron ore, whereas the feed section identifies iron-ore tailings; this terminology is retained without changing processing origin.
Support
Source:
borkar2026
Section 3.1 and Figure 7 report cumulative assayed iron amounts over 123 days of 4.71 g from the first stage and 0.22 g in the manganese-stage overflow. The text calls their approximately 21-fold difference a concentration comparison, but the graph and values have mass units. These cumulative amounts are not a direct phase-specific dissolution rate or a closed iron balance; precipitation after oxidation is the authors' proposed explanation for reduced downstream iron.
Partial
Source:
borkar2026
Sections 3.1–3.3 compare the two-stage experiment with single-stage biotic and abiotic experiments from earlier studies, references 7 and 13. They are historical comparisons, not matched contemporaneous two-stage controls. The paper does not provide a sterile two-stage or matched chemical-Fe(II) comparator that isolates microbial necessity or the relative acid and iron contributions. Section 3.6 explicitly allows microbial carryover into the manganese stage and states that dominant organisms and relative activities were not assessed. Thus the second stage is not established as cell-free, and no taxon-specific or mineral-specific causal claim is made.
Partial
Source:
borkar2026
Sections 2.5 and 3.4–3.6 also describe a 19 L bench-scale tank system, termed a small pilot by the authors. Table 6 calls its 20 kg iron charge iron ore, without a separate batch assay. No industrial deployment, economic viability or universal tailings treatment performance follows from either apparatus. This and the manganese-ore record describe linked stages of the same study, not independent replications.
Sources & References
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borkar2026: Borkar, Sharma, Rane, Boafo and Eisele (2026). Leaching of Manganese Using Bio-solubilized Iron Reductant to Prevent Manganese Carbonate Formation. Mining, Metallurgy & Exploration 43:2019–2030. DOI 10.1007/s42461-026-01506-2; Methods 2.1–2.6, Tables 1–7, Figures 5–13 and Results 3.1–3.6. Full 12-page primary article and figures inspected.
https://doi.org/10.1007/s42461-026-01506-2 (accessed 2026-10-11)
Curation History
| Timestamp | Curator | Action | Summary |
|---|---|---|---|
2026-10-11T11:42:56.094430+00:00 |
codex (GPT-6; codex) | CREATE | Created resource identity and narrowly scoped primary two-stage bioleaching evidence, preserving controls, analytical basis and scale limitations. |
Record source: data/records/iron-ore-tailings.yaml