Exploration and Discovery at the Petaquilla Copper-Gold Concession, Panama
Bibliographic record
Abstract
Abstract The Petaquilla concession in central Panama hosts three major porphyry Cu-(Au-Mo) deposits, with total reserves of 1,218 million tonnes (Mt) grading 0.50 percent Cu, and 0.08 g/t Au, as well as the 570,000 oz Molejon low-sulfidation epithermal gold deposit. The main porphyry deposits on the property (Petaquilla, Botija, and Valle Grande-Vega) form east-southeast-trending elongate bodies that range from shallowly dipping and tabular (Petaquilla and Botija) to funnel-shaped (Valle Grande-Vega) in morphology. Alteration includes a central potassic facies, grading outward to silica-chlorite and variably developed propylitic facies. Phyllic alteration appears to be an overprint. At surface, quartz stockworks are associated with phyllic alteration, whereas at depth, they are associated with the potassic facies. Mineralization is pyrite-dominant at surface, but chalcopyrite-domi-nant at shallow depth. Bornite appears at deeper levels at Botija, and oxide-dominant assemblages are found in the deepest parts of that deposit. Molybdenite is common in the higher grade portions of the deposits. Highest copper and often, also gold grades are found where the phyllic and potassic facies overlap, or in propylitically altered contact metasomatic zones. At Molejon, gold mineralization occurs in multiphase, northeast-striking and shallowly north-dipping limonitic quartz-carbonate veins and vein breccias, and to a lesser extent, as disseminations in altered intrusive rock or in quartz stockworks. Geochemical exploration methods, combined with geologic observations, played a key role in the discovery of copper and gold deposits. Airborne magnetic data and radiometric data as well as ground magnetics permit discrimination between intrusive and volcanic rocks, between different suites of intrusive complexes, and between unaltered and altered rocks. Porphyry centers can be recognized in the field by the presence of strong, texturally destructive silicic-phyllic alteration with abundant pyrite, quartz-limonite, quartz-sulfide or quartz-magnetite stockworks, extensive zones of mineralized contact metasomatic rock, and multiple intrusive phases.
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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 | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| 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".