Spatial and Temporal Fluctuations of Pore‐Gas Composition in Sulfidic Mine Waste Rock
Bibliographic record
Abstract
Core Ideas Grain‐size segregation during end dumping affects the pore‐gas distribution. Seasonal variations in precipitation affect O 2 ingress and CO 2 egress. Hot spots of sulfide oxidation are controlled by physical and chemical heterogeneity. Grain‐size segregation is reflected in the spatial distribution of oxidation rates. The oxidation of sulfide minerals and pH‐neutralization reactions in unsaturated mine waste rock produce changes in the pore‐gas composition, leading to substantial deviations from atmospheric conditions. We studied the temporal and spatial changes in pore‐gas composition, temperature, and volumetric water content (VWC) in an experimental pile during a 2‐yr period. The pile was constructed by end dumping and is exposed to a marked two‐season (wet–dry) climate. The grain‐size segregation of waste rock occurring during end‐dump construction significantly affected the spatial distribution of pore‐gas composition within the pile. Results from continuous monitoring also demonstrated the role of VWC fluctuations on pore‐gas composition at the study site. Oxygen decreased during the wet season, while CO 2 concentrations showed the opposite behavior. Gaseous diffusion was inferred as an important O 2 supply mechanism for this experimental waste‐rock pile. In addition, wind‐induced gas advection and convection probably contributed to O 2 ingress into the basal regions of the pile. Intrinsic oxidation rates were estimated based on one‐dimensional reaction–diffusion modeling, showing pronounced variations between the top and bottom of the pile. These differences can be attributed to low reactivity in the basal region of the pile related to the coarse‐grained nature of the material and the omission of O 2 –supply mechanisms other than diffusion. The results demonstrate the complex interactions between physical and chemical heterogeneities in mine waste rock and contribute to an improved understanding of oxidation reactions and metal release that occur in sulfidic waste rock.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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) | 0.001 | 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 teacher head, 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".