Underground mining at Ekati and Diavik diamond mines
Bibliographic record
Abstract
Primary diamond deposits have been mined on an industrial scale only within the past 150 years, mainly as open pit mines. Although underground mining followed soon after open pits reached technical and/or economic limits, it only gained significant recognition in the past 20 years with the exception of Kimberley Mines. A relatively large number of underground mining methods were tested, implemented, and evolved mainly in South African mines. In the mid-1990s, Alrosa also started the development of the first underground diamond mine in Russia, Internationalnaya. Since then, underground mining has been implemented in several of their mines including Aikhal, Mir, and Udachny. China had also experimented with underground mining at Nhangma 701 Diamond Mine at the end of the nineties, but the largest development of underground diamond mining was experienced in Canada. Today, out of some 50 active diamond mines mining kimberlite or lamproite, approximately 15 are underground and another 15 have underground plans or hold the potential. Ekati Diamond Mine is the first diamond mine to be developed near Lac de Gras in the Northwest Territories of Canada. The Koala North pipe had been developed and mined as an open pit; then later as a mechanised open benching operation to test the underground mining method and to provide access to the lower parts of the Panda and Koala pipes. Both the Panda and Koala pipes were also developed and mined underground once the open pit operations were completed. Koala North, North America’s first underground diamond mining operation, was formally opened in 2002. Three principal underground mining methods: open benching, sublevel caving and incline cave mining were implemented at the Ekati mine. Diavik Diamond Mine started open pit production in 2003. By 2005, underground development had commenced with plans to mine the A154 and A418 pipes using backfill methods. As geotechnical knowledge was gained, the mining methods were re-evaluated and the sublevel retreat (SLR) method was chosen for the A154S and A418 pipes, and blasthole stoping (BHS) with cemented rockfill (CRF) was chosen for the A154N pipe. In 2012, the open pits reached their ultimate depths and Diavik became a fully underground operation. The current mine life is approximately 2025. In 2008, De Beers started underground mining on kimberlite sill at Snap Lake. However, the mine closed in 2015 and it is currently on care and maintenance. The focus of this paper is to document experiences with underground mining of kimberlite pipes at the Ekati and Diavik mines.
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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 | 0.001 | 0.001 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
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".