Analytical solution for determining wall closure associated with stope excavation underneath sill mat constructed by cemented backfill
Bibliographic record
Abstract
In the underhand cut-and-fill mining method, a sill mat (i.e. an artificial horizontal pillar) constructed by cemented backfill is essential to prevent mine workers from being directly exposed under problematic rock roofs. A critical issue is to determine the minimum required strength of the sill mat to ensure a safe and cost-effective design. Until now, Mitchell's analytical solution is the only available option, considering two stiff and immobile rock walls. Unavoidable rock wall closure associated with stope excavation below the sill mat was neglected. This, along with other undefined parameters, explains why Mitchell's solution is rarely used in sill mat design. A new analytical solution for determining the minimum required strength of the sill mat accounting for wall closure is necessary. In this study, a closed-form analytical solution for estimating rock wall closure generated by stope excavation below a sill mat is developed by using Salamon's and Flamant's models. The proposed analytical solution does not contain any coefficients of correction or calibration. Despite several assumptions (or somewhat of oversimplifications) necessary to render a simple analytical solution possible, good agreements are obtained between the rock wall closures predicted by applying the proposed analytical solution and those obtained numerically with FLAC3D for many cases with arbitrarily chosen geometrical and material parameters. The proposed analytical solution is therefore validated and can be used to evaluate the rock wall closure generated by stope excavation below a sill mat.
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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 | 0.001 | 0.003 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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".