Delineation of Regolith Zones in Nickel Laterite using Electromagnetic Imaging: Ravensthorpe, Western Australia.
Bibliographic record
Abstract
Nickel laterite is a product of intensive weathering processes of ultramafic rocks near the surface. The Ravensthorpe Nickel Operation has traditionally used boreholes spaced at 40 meters to delineate the major regolith zones of caprock, limonite, saprolite, and saprock. The high geometric complexity of the weathering profile leads to an inaccurate resource delineation by drilling alone. Loupe is a new ground system for transient or time-domain electromagnetic measurements suitable for resolving shallow electrical conductivity distribution. At Ravensthorpe, the technique was tested in 2019 to improve the spatial resolution of conductivity models and, consequently, to better distinguish different regolith zones. Appraisal of the Loupe system involved experimentation with different transmitter waveforms, assessment of diffusion depths and noise levels, and 1D inversions with and without constraining geological input. Interpretation of the inverted conductivity suggests that the Loupe data are imaging the caprock thickness and reproducing the thinner but continuous conductive zones defined by downhole logging within certain segments of the regolith profile. Below the caprock, the conductivity correlates with higher clay proportion, as defined in visual logging and reflected in higher Al content.
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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 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| 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".