Preparation and conduction of a production blast at an intersection in Kirov Mine, Apatit
Bibliographic record
Abstract
Apatit company mines apatite–nepheline ore using mainly the underground method which produces more than 70 % of the overall minerals extracted. In accord with the accepted mining technology, the operating horizons are developed from the center to the sides, with one or two cuts to get to another level. When two cuts are made on a horizon, in order to reach the required production output, two mining fronts are advanced toward each other, which results in formation of a block–pillar, and this intersection is cut at the end of the horizon development. After the analysis of the actual geotechnical, geological and geomechanical conditions, a production blast to break the intersection in Kirov Mine has been evaluated and prepared. Total volume broken by the blast is 726 thou t. Overall weight of explosive to break this intersection is 320 thou kg. Based on the geometry of the intersection and the number of blast hole rings, it has been decided to blast the holes from the sides toward the center of the intersection. As per the seismic safety standards, maximum weight of explosive per delay stage is evaluated, and blasting patterns and sequence are described. Considering particulars of the production blast in the intersection, the classical scheme of nonelectric blasting was used in combination with the electronic blast initiation system EBIS i-kon II manufactured by Orica CIS, which allowed blasting with seismically safe weight of explosive per delay stage. The production blast at the intersection used 1500 electronic detonators (total number of borehole charges was 2050). EBIS were installed in the blasthole rings, but their simultaneous blasting endangered the seismic safety. In blasting per rows with seismically unsafe weight of explosive per delay stage, the rings of holes were blasted uniformly, with a delay of 3–5 ms between the holes. The control and execution blocks had modem communication. Blasting was executed from the surface by means of telephone circuit. Orica CIS personnel controlled actuation of each delay stage using a special program. Seismic eff ect of the blast on buildings and structures was estimated using Instantel equipment (Canada) including 8-channel seismic measuring devices Minimate Plus. Actual PPV at all measurement points were below the maximum allowable values. The production blasting with the electronic initiation systems has yielded higher quality fragmentation of ore with the ensured seismic safety of the surface buildings and structures.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 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".