Numerical modelling and rescaled range analysis on spontaneous combustion under surface methane drainage in a Chinese coal mine
Bibliographic record
Abstract
In China, surface boreholes have been used frequently to drain methane/gas emitting from overlying layers and longwall mining gob areas in underground gassy coal mines. In this work, a numerical modeling was established using COMSOL TM to study the influence of surface drainage borehole on coal spontaneous combustion and Rescaled Range Analysis (R/S analysis) was employed to investigate the chaos characteristic of Nitrogen (N 2 )/Oxygen (O 2 ) drained from the gob. The simulation results show that there is a circular “dissipation zone” around the drainage borehole all the time and an elliptic “spontaneous combustion zone” when the borehole locates in deep gob. It is also found that the advancement of drainage borehole has little influence on spontaneous combustion zone on the intake side of the gob but it can tremendously enlarge the width of “spontaneous combustion zone” in the middle gob and reduce the depth of self-heating zone near the return side. The R/S analysis indicates that the influence of surface borehole on spontaneous combustion can be divided into two stages: the safety drainage stage (Hurst index > 0.85) and the spontaneous combustion initiating stage (Hurst index ≤ 0.85). It can be concluded that the gas drainage from gob through surface borehole can tremendously intervene spontaneous combustion three zones in gob. In addition, the length-fixed R/S analysis on N 2 / O 2 series from surface boreholes can effectively reflect coal spontaneous combustion condition in gob.
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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 | 0.001 |
| 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) | 0.000 | 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 teacher head, 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".