The formation-dissolution-precipitation cycle of melanterite at the abandoned pyrite mine of Genna Luas in Sardinia, Italy: environmental implications
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Bibliographic record
Abstract
Abstract At the abandoned pyrite mine at Genna Luas (Sardinia, Italy), melanterite is the most environmentally important secondary phase associated with pyrite oxidation. A complete cycle, including formation on pyrite surface, dissolution in water, precipitation from water and subsequent alteration, can be observed. The oxidation of pyrite to melanterite is related mainly to the ‘intrinsic’ features of the Genna Luas pyrite, such as its cryptocrystalline pseudo-colloidal texture. During melanterite formation on pyrite there is transient storage of Fe 2+ , SO 4 2- and acidity. This is controlled mainly by wetting-drying seasonal cycles. Laboratory experiments have shown that the simple dissolution of melanterite is an acidity-generating process which affects the geochemistry of water and, indirectly, contributes to the supply of the Fe 3+ required for the aqueous oxidation of pyrite. According to this geochemical model, the interaction between rainwaters and ground pyritic materials accumulated in heaps generates hyperacidic saline waters (pH = 0.6; TDS = 300 g/l) with very high SO 4 2+ contents (203 g/l), Fe 2+ contents (73 g/l), Zn contents (11 g/l), and numerous potentially toxic elements. Melanterite precipitates from these waters (SI Melanterite = 0.15, calculated using PHRQPITZ software), giving rise to attractive emerald green crystal aggregates which, when exposed to air, alter to a fine white powder composed mainly of melanterite, and minor amounts of rozenite and szomolnokite.
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Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| 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) | 0.003 | 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 it