Performance of Insulation Covers to Control Acid Mine Drainage in Cold Environments
Bibliographic record
Abstract
Performance of a 1.2 m thick insulation cover constructed on the Xstrata Nickel Raglan Mine tailings storage facility was assessed in situ. The mine is located in the Northern part of the province of Quebec, Canada, in the continuous permafrost zone. The methods used in this study to quantify the performance of the insulation cover include oxygen consumption tests to assess the tailings reactivity and temperature measurements at various depths in the cover material and sulfide tailings. The oxygen consumption test consists of measuring the decrease in oxygen concentration in a sealed chamber and, using fundamental gas diffusion laws, to calculate the oxygen flux through the tailings surface, the oxygen consumption can be related to the tailings oxidation. Three stations were installed directly in the tailings without insulation cover and three under the 1.2 m insulation cover. Oxygen consumption reached a maximum value of 544 moles⋅m-2⋅year-1 for the non-covered stations during August when the tailings temperature was 12.8°C. Oxygen consumption drops with temperature and is close to zero at about -4 °C. For the covered stations, oxygen consumption is low in August and tends to increase from September to the end of October, to reach a maximum value of 444 moles⋅m-2 ⋅year-1. Tailings reactivity decreases in December when tailings temperature drops to approximately -5°C. These results show that, when the tailings are not preserved from freeze-thaw cycles, even with a granular insulation cover of 1.2 m, the sulfide contained in the tailings can oxidize. Moreover, the tailings can still oxide at subzero temperature.
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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 | 0.000 | 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".