Graphical representation of production results versus estimates in placer mining
Bibliographic record
Abstract
Placer deposits are renowned for the difficulties inherent in the estimation of their mineral reserves. Mining and treatment often produce a recovered grade very different from that originally estimated. A measure traditionally used in the placer mining industry to report such technical performance is the ratio of recovered grade to estimated grade. The ratio, referred to as a factor, is determined and reported for a specified duration of continuous mining or for a mining block size. Over the life of mine numerous data pairs are generated for the estimated grade and the corresponding factor. The frequently inverse relationship between the two measures is expressed graphically on a scatter plot. Logarithmic scales are used for both the independent variable (estimated grade) and the dependent variable (factor). The factor may vary widely, and best-fit trend lines are derived by using either power or quadratic polynomial formulae. The relative estimated grade (each estimate divided by the average of all estimates of grade within the mined extent of a placer) may replace estimated grade as the independent variable. The graphical representation allows performance to be compared and contrasted for different mineral placers and mining methods employing diverse units of grade measurement.Model trend lines result from the direction of mining in the longitudinal and transverse dimensions of the placer. The mining site, whether in the proximal or distal zone of the placer, also influences the form of the model. Other parameters, apart from estimated grade, affect the factor. They include sample support, sample spacing and method of mining. Sampling density and the duration of the reporting period determine the degree of slope and the curvature of the trend line. An important model results from attempting to exploit marginal grade outliers. Uses of the plot include monitoring the effects of changes in operational policy, mine planning and revenue forecasting. The average, historic factor achieved in a deposit, in places used as a correction factor, is not always a reliable indicator of future performance in the same placer. Care should be applied when using such a factor to substantiate reserve estimates. The simple graphical technique continues to be employed, and its application is not limited to placers.
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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 | 0.027 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.006 | 0.004 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.003 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.043 | 0.007 |
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".