Evolution of kimberlite exploration – systematic exploration using a ground geophysical toolbox for kimberlites, Slave Craton, NT, Canada
Bibliographic record
Abstract
Diamond exploration in the Slave Craton within the Northwest Territories of Canada has been ongoing since the first kimberlite discovery at Point Lake kimberlite in 1991. Thousands of sediment samples have been collected and hundreds, if not thousands, of geophysical surveys have been completed over the past three decades. The results of which have, at times, perplexed explorers, demonstrating that the search for kimberlites is complex and that no silver bullet exists for their discovery. Recently, a more systematic approach to exploration has shown that despite these challenges, there is still great potential to discover economic kimberlites in the Slave Craton. The Kennady North Project (a wholly-owned subsidiary of Mountain Province Diamonds Inc.) has established that a program that methodically incorporates drill targeting and drill hole results systematically with till sampling, airborne geophysics and a toolbox of ground-based geophysics is critical to kimberlite discovery. Applying this systematic approach has led to the discovery of the Kelvin and Faraday kimberlites, which had previously eluded explorers, at least partially due to the bias of searching for the classic “vertical carrot-style” emplacement model. The Kelvin and Faraday kimberlites instead demonstrate emplacement at inclined angles, which produce different geophysical responses, have much smaller surface expressions, yet still contain significant economic potential. A tailored ground geophysical toolbox comprising electromagnetics [horizontal loop (HLEM)], gravity, resistivity surveys [capacitively-coupled (CCR) and snowmobile-towed] and magnetics helped to guide drill targeting at the Kennady North Project. This drill targeting assisted with the identification and delineation of the Kelvin kimberlite into an 8.5 million tonne indicated resource with 13.62 million carats and the Faraday 2 and 3 kimberlites into an inferred resource of 3.94 million tonnes with 7.35 million carats (Vivian et al. 2019 ).
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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 | 0.002 | 0.003 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.005 | 0.005 |
| Science and technology studies | 0.005 | 0.006 |
| Scholarly communication | 0.004 | 0.001 |
| Open science | 0.002 | 0.004 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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".