Occurrence characteristics of Sr in coal from Tashan Coal Mine in Datong,Shanxi Province
Bibliographic record
Abstract
Datong Coalfield was intruded by igneous intrusions in both the Indosinian (Late Permian to the end of the Triassic) and the Yanshan (Late Jurassic to the Early Cretaceous) periods，which caused contact metamorphism of the coal seam. Previous studies have shown that Sr is significantly enriched in coal from the 5222 tunnel of the Tashan coal mine. The maximum concentration of Sr in thermally-altered and unaffected coal is 3067 μg/g and 2729 μg/g respectively, and the average concentration of Sr is 1165 μg/g, which is 10.6times of the world average level in hard coal. However, the modes of occurrence of Sr in the Tashan coal still remain unclear. Samples in the 5222 tunnel including coal and intrusive rock were systematically collected. Inductively coupled plasma mass spectrometry (ICP-MS) and X-ray fluorescence spectrometry (XRF) were applied to elucidate Sr concentration variations in the sample; correlation analysis, scanning electron microscope with energy spectrum (SEM-EDS), and sequential chemical extraction procedure (SCEP) were carried out to reveal the occurrence modes of Sr, as well as the characteristics of Sr-bearing minerals. The results demonstrated that Sr exhibits a strong correlation with P2O5 in coal; Sr mainly occurs in phosphate (apatite) and clay minerals that are intimately associated; apatite was distinguished as fluorapatite in the shape of hexagonal columns and hydroxyapatite in the shape of fine scattered particles embedded in the clay minerals.
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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 | 0.001 | 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) | 0.000 | 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".