Oxidation of mine tailings from Rankin Inlet, Nunavut, at subzero temperatures
Bibliographic record
Abstract
Acid-generating sulphidic tailings from a NiCu mine were exposed on the shores of Hudson Bay for 30 years before burial in a drained bedrock basin. To determine if encapsulation in permafrost will maintain the tailings, and their saline pore water, in a chemically inert state, a field and experimental program was employed. Three years after burial, several boreholes were drilled to collect tailings and pore-water samples and to initiate long-term thermal monitoring. Columns charged with pyrrhotite-bearing, unsaturated tailings were studied at temperatures between +30°C and 10°C. Oxygen consumption was measured directly to determine the effect of low temperatures on oxidation rate. Results of the column experiments indicate that significant oxidation of the Rankin Inlet tailings occurs at +30°C, but at lower temperatures this rate is substantially reduced. At 10°C, unfrozen water was still present in the columns, but oxygen consumption was below the detection limit. The highest measured oxygen flux correlates with a temperature increase of 1°C, consistent with exothermic sulphide oxidation reactions. Thermal modeling and direct measurements have shown that the freezing of the tailings in Rankin Inlet is progressing. The tailings are expected to be ice-bonded approximately 15 years after burial.Key words: acid mine drainage, permafrost, tailings, reclamation, sulphides, oxidation
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".