Pore-gas dynamics in overburden and reclamation soil covers
Bibliographic record
Abstract
Pore-gas dynamics in single-layered and multi-layered soil covers were characterised in a mine cover testing programme for the reclamation of lean oil sand overburden. Pore-gas concentrations of oxygen and carbon dioxide in the upper 1·5 m of soil covers and overburden did not reach the threshold that poses a risk for plant growth. Below 1·5 m in the overburden, however, oxygen dropped to 0% and carbon dioxide rose to >16%. While methane concentrations were typically <1·7%, there was a peak in methane at one sampling location to concentrations >35%. Novel subsurface flux chambers were designed and fabricated to measure directly oxygen ingress through soil covers and carbon dioxide efflux from overburden into soil covers. Oxygen fluxes peaked at 18·0 kg/(m2 a) and carbon dioxide fluxes peaked at 2·3 kg/(m2 a). Soil cover material and placement thickness affected gas flux rates. Diffusive fluxes were calculated from soil gas profiles by estimating diffusion coefficients from position-dependent soil moisture and temperature. Advective fluxes were calculated from pressure gradients and in situ air conductivity. Advection dominated over diffusion in soil covers except for one location that was either a localised zone of microbial activity (hydrocarbon degradation or methane oxidation) or the overburden was coarser textured and responded quickly to barometric pressure fluctuations.
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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".