Results of the Radius Factor Stability Assessment Method for Design and Pillar Extraction at the Conqueror Mine, St Ives Gold Mine
Bibliographic record
Abstract
A reliable stability assessment for stoping is critical at the design stage of mining and the Conqueror mine at Gold Fields’ St Ives operations is no exception. The mining method at Conqueror was longhole open stoping with diminishing rib to island pillars. The Mathews Stability Graph Method (SG) was initially used to assess the Conqueror primary stopes but proved unwieldily with the onset of the extraction of the secondary stopes from rib to island pillars. The St Ives Geotechnical Department therefore had to search for an alternative stability assessment method. A Canadian stability method, Radius Factor (Milne, 1996), was investigated and subsequently trialled. Whilst Hydraulic Radius as considered in the Stability Graph method is based on boundary geometry (length x width), the Radius Factor method is based on surface geometry. Two new terms were introduced to site personnel, Radius Factor (RF) is related to the overall stability and maximum deformation of a surface and Effective Radius Factor (ERF) is related to the local stability and deformation of a point on the stope surface. The method was trialled firstly as a tool to back analyse old stoping areas. Back analysis showed the method to be effective for determining maximum stable spans. The method was then used as a design tool for determining maximum spans and pillar placement in the mine design. The Radius Factor method was continually calibrated to actual mine results over the life of the mine. This calibration enabled stope geometry and sequencing changes to incorporate best geotechnical practice into the mine extraction sequence. As a result the St Ives geotechnical and mining teams were able to safely extend two stope lengths and extract one central pillar resulting in an extra 404 kg.
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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 | 0.003 | 0.007 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
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".