Ground support challenges in arctic mining conditions
Bibliographic record
Abstract
The Meliadine and Amaruq mines, inaugurated by Agnico Eagle in 2019, are located in the Canadian Arctic, in areas of deep and continuous permafrost. Excavation of the exploration ramp at Meliadine started in 2013 and at Amaruq in 2017. These underground mines are being developed in conditions that vary from perennially frozen rock, through a transition zone where the rock temperature is below 0°C but where groundwater may be present in a liquid state depending on its salinity, to rock masses with a temperature perennially above 0°C. Brine is required as service water and for all drilling activities in permafrost but may be replaced by naturally saline groundwater below the permafrost. Ambient air conditions underground vary seasonally with depth and following ventilation patterns. As such, ground support elements and materials need to be adapted to the temperature and environmental conditions specific to each stage of mine development and operation. During the initial stages of ramp development, the freezing air and rock temperatures encountered throughout most of the year make the use of resin-grouted rebar difficult. The primary ground support within the permafrost areas therefore consists of inflatable bolts and friction bolts with mesh. As the mine progresses deeper and equipment becomes available, resin-grouted rebar and cement-grouted cable bolts are introduced. The integration and implementation of each type of ground support element require testing and the development of quality assurance and/or quality control protocols. Heating mine air in an arctic environment is costly and was a matter of debate during the project evaluation and development phase. The experience at Meliadine has shown that very cold air in the presence of groundwater can lead to the rapid formation of ice in joints, causing the premature failure of ground support elements. It is concluded that the combined presence of groundwater and freezing temperatures is problematic and that mine air heating is required in such conditions.
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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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.004 | 0.001 |
| Scholarly communication | 0.003 | 0.001 |
| Open science | 0.001 | 0.003 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.008 | 0.002 |
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".