A 9-year study of the degradation of a HDPE geomembrane liner used in different high pH mining applications
Bibliographic record
Abstract
The degradation of a HDPE geomembrane in heap leaching environments is evaluated using immersion tests at five temperatures. The incubation solutions had a pH of 9.5, 11.5, and 13.5, relevant to gold and silver pregnant liquor solutions. After 9.3 years, the geomembrane's mechanical properties had reached nominal failure at 95, 85, and 75 °C in all three solutions. It is shown that the pH 13.5 solution had the greatest effect on the antioxidant depletion (Stage I) and polymer degradation (Stage III), but was the least aggressive to initiate the degradation (Stage II) compared to the pH 11.5 and 9.5 solutions. Overall, the time to nominal failure (time to 50% of the initial or specified property value) in pH 13.5 was slightly shorter than the pH 9.5 and 11.5 solutions. Based purely on immsersion tests, the time to nominal failure of this specific geeomembrane at 30 o C is predicted to be 150 years in the pH 9.5 and 11.5 solutions, and 140 years in the pH 13.5 solution. Assuming a good liner design that limits the tensile strains in the GMB, nominal failure in a composite liner configuration is predicted to exceed 260 years at 30 °C and the expected value could exceed 1000 years at 10 °C. • Examines the effect of increasing the pH of heap leaching solutions from 9.5 to 13.5 on the properties of the geomembrane. • Compares the effect of the length of incubation duration on antioxidant depletion times. • Uses Arrhenius modelling to extrapolate the time to nominal failure at field temperatures. • Estimates time to nominal failure in a composite liner configuration.
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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 | 0.001 |
| 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 | 0.001 | 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 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".