Mineralogy and Weathering of Realgar-Rich Tailings At a Former As-Sb-Cr Mine At Lojane, North Macedonia
Bibliographic record
Abstract
In the Lojane area (North Macedonia) ores of Sb (stibnite), As (realgar), and Cr (chromite) were mined and processed in a metallurgical plant until 1979. Over one million tons of flotation tailings containing As, Sb, and other hazardous substances are located in an open dump site for flotation waste created by the mine. The tailings site is completely unprotected, and its orange color reflects a very high concentration of arsenic (fine-grained realgar superficially altered to pararealgar). In order to better understand the weathering behavior of these tailings, which is necessary to evaluate the environmental risks (mainly from the mobilization of As-Sb-Cr), solid waste material was sampled and studied from the chemical and mineralogical point of view. The material was characterized by inductively coupled plasma-mass spectrometry (ICP-MS), inductively coupled plasmaoptical emission spectrometry (ICP-OES), X-ray diffraction analysis (both single crystal and powder), scanning electron microscopy (SEM) with energy-dispersive microanalysis (EDX), Raman spectroscopy, and transmission electron microscopy (TEM) with selected area electron diffraction (SAED), energy-dispersive X-ray analysis (EDX), and electron energy loss spectrometry (EELS). The studied tailings material is comprised mostly of well-crystallized realgar, gypsum, and quartz, and minor amounts of stibnite, pararealgar, chromite, and sulfur. Very minor pyrite is found within quartz aggregates. The most abundant secondary phase, which forms thin coatings around realgar and stibnite grains, is an As-Sb-Fe-Ca-(Ni)-oxide/ hydroxide in which the As:Sb ratio varies from ca. 2:1 to 1:2.2 and Fe contents are variable. Antimony-dominant variants of this oxide also form larger homogeneous grains up to 500 lm in size, characterized by broad dehydration cracks suggesting original formation as a gel. Both As-rich and -poor variants were identified as members of the rom´eite group. EELS showed that all the Fe is ferric. Further secondary phases originated from the weathering of realgar, stibnite, and other primary phases are As-bearing sulfur, scorodite (often slightly Sb-bearing, locally common), arsenolite, ‘‘limonite’’, pickeringite (Ni- and Febearing), alunogen, and annabergite. The weathering of primary sulfides in the flotation tailings at Lojane proceeded under mostly oxidizing, acidic, and temporarily wet conditions. Highly acidic conditions on the surface of the tailings dump imply dissolution of arsenolite and scorodite, thus causing contamination of the environment and high mobility of arsenic.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.005 | 0.002 |
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; both teacher heads agree on what is shown here.
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".