Permafrost Drilling-Waste Sump Integrity in the Sahtú Region, central Mackenzie Valley, NT, Canada.
Bibliographic record
Abstract
Waste-containment sites built in thaw-sensitive permafrost terrain of Northwestern Canada have shown persistent instability over the past century as their intended containment medium, permafrost, degrades under a warming climate. This thesis evaluates the integrity of five drilling-waste sumps containing contaminants in the subsurface, whether in frozen or unfrozen ground. We assess the extent to which permafrost in these drilling-sumps continues to fulfill its intended containment function. Our initial inventory of sump presence and status across the Sahtú region, NWT can be used to suggest accessible, high-priority sites for future ground-based investigations. This research contributes a foundation for sump risk assessment and emphasizes the need for expanded monitoring, collaborative management, and integration of Indigenous knowledge systems to inform future remediation and climate-resilient land-use planning in the Sahtú region. To advance our understanding of drilling-waste sump performance in discontinuous permafrost, we conducted electrical resistivity tomography (ERT) and induced polarization (IP) surveys, frost probing, shallow borehole coring, and ground temperature monitoring between 2022-2024. These methods were used to detect permafrost and/or thawed zones in sumps and map the potential mobilization of saline contaminants. Water sampling and analysis for trace metals and major ions further supported these observations. These field data were supplemented by publicly available records and regulatory reports, including those from the Mackenzie Valley Land & Water Board and the Office of the Regulator of Oil and Gas Operations. Results from five field site investigations indicate that while permafrost remains present at or near several sumps, permafrost thaw and movement of high-chargeability fluids to the surface suggest that containment integrity has been compromised in multiple sumps. Fieldwork was completed primarily by team members of the Permafrost Archives Laboratory at the University of Alberta, and in partnership with the Sahtú Renewable Resources Board through the Petroleum Histories Project. Assessments of drilling-waste sumps in boreal regions are significantly more complex and costly than in more accessible areas, largely due to the remoteness of sites, infrastructure costs, and the vulnerability of discontinuous permafrost to disturbance. This work highlights limitations in historical documentation, regulatory data gaps, and challenges with older sumps now re-vegetated and difficult to access. Sustained funding to support further site-specific studies that can guide climate-resilient remediation planning and land-use decisions can help ensure informed, coordinated approaches to managing legacy oil and gas infrastructure in the Sahtú.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| 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 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".