Surficial exploration methods for detecting low sulfide high precious metal and Ni-Cu-PGE mineralization in glaciated terrain
Bibliographic record
Abstract
The increasing difficulty of finding near-surface mineral deposits in glaciated terrain requires modification of conventional exploration techniques (drift prospecting) that can assist in exploring for deposits buried under glacial sediment cover of variable thickness. To address this challenge, a humus and soil (developed in till; “C-horizon till”) sampling study was conducted in the Drury and Denison townships in the South Range of the Sudbury Igneous Complex (SIC) to develop surficial mineral exploration techniques that are suitable for low sulfide, high precious metal (LSHPM) and massive sulfide Ni-Cu-PGE mineralization. The objectives of this project were to assess the suitability of humus and till for delineating geochemical anomalies in an established mining camp (the Sudbury Mining Camp) and characterize the chemistry of chalcopyrite, pentlandite and sperrylite grains in till derived from LSHPM (the Vermilion Cu-Ni-PGE-Au deposit) and Ni-Cu-PGE (the Crean Hill deposit) mineralization. Results of this study suggest that the natural geochemical signature of humus in the Sudbury Mining Camp is strongly overprinted by anthropogenic contamination such that the geogenic signal is only apparent in humus samples collected in the vicinity of known Ni-Cu-PGE mineralization. Glacial dispersal from Ni-Cu-PGE mineralization is apparent in C-horizon till and compared to the background (up-ice) concentrations, the C-horizon till samples collected immediately down-ice of the Vermilion deposit are enriched over 20 times in Pt, Au, and Cu, and over 30 times in Ni. Pathfinder elements that show a strong, positive correlation with Ni, Cu, Au, and PGEs (Pt, Pd, Ru, Rh, and Ir), that are also derived from LSHPM and Ni-Cu-PGE mineralization are As, Bi, Co, Cr, Pb, Sb, and Te. Ore minerals that survive glacial transport and post-glacial weathering and are the best indicators of Ni-Cu-PGE-Au mineralization are chalcopyrite, sperrylite, and gold grains. Glacial modification of ore minerals is limited to physical comminution and does not affect their chemical composition. Precious metals are detected in ore minerals derived from LSHPM mineralization. These consist of Ag, Au, Ir, and Pt in chalcopyrite, Ag, Au, Pt, Pd, Rh, and Ru in pentlandite and Ag, Au, Ir, Pd, Rh, and Ru in sperrylite.
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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 | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 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".