Room and Pillar Recovery
Estimate plan-area extraction for rectangular repeating cells and caller secondary pillar recovery; excludes seam losses and stability recommendations.
Description
Room-and-pillar plan extraction compares the pillar footprint with its repeating room-plus-pillar cell.
Room-and-pillar plan extraction compares the pillar footprint with its repeating room-plus-pillar cell. Secondary extraction removes a supplied fraction of what initially remains.
The tool returns primaryPlanExtractionFraction (primary plan extraction fraction); totalPlanExtractionFraction (total plan extraction fraction). Input measurements and model parameters are supplied by the caller; the tool computes the stated summary rather than acquiring those measurements.
When to use Room and Pillar Recovery
Use Room and Pillar Recovery when you already have pillarWidthM, pillarLengthM, roomWidthAcrossM, roomWidthAlongM, secondaryPillarExtractionFraction and want primaryPlanExtractionFraction, totalPlanExtractionFraction. This is useful for checking a supplied calculation, documenting a measurement convention, or comparing observations prepared on the same basis.
How to use Room and Pillar Recovery and understand its results
- Enter pillarWidthM, pillarLengthM, roomWidthAcrossM, roomWidthAlongM, secondaryPillarExtractionFraction using the field table below. Match the units, ordering and data boundaries described in the calculation.
- Run the tool after checking the stated bounds and matching paired observations or categories. A malformed request gives a tool error rather than a usable measurement.
- Read primaryPlanExtractionFraction, totalPlanExtractionFraction. Use the calculation and interpretation below to distinguish amounts, ratios, signs and decision flags where applicable.
- Review the supplied parameters and assumptions before using the result in a report or comparing it with another observation.
| Input field | Meaning | Value type and bounds | Requirement |
|---|---|---|---|
| pillarWidthM | Pillar width m | number | Required |
| pillarLengthM | Pillar length m | number | Required |
| roomWidthAcrossM | Room width across m | number | Required |
| roomWidthAlongM | Room width along m | number | Required |
| secondaryPillarExtractionFraction | Secondary pillar extraction fraction | number | Required |
Use positive pillar dimensions, nonnegative across/along room widths and secondary fraction in [0,1].
primary = 1−pillarArea/cellArea; total = 1−remainingFraction×(1−secondaryExtraction) The symbols refer to the supplied quantities or generated values described above; unit conversions and comparison boundaries follow the stated implementation.
{
"input": {
"pillarWidthM": 10,
"pillarLengthM": 20,
"roomWidthAcrossM": 5,
"roomWidthAlongM": 10,
"secondaryPillarExtractionFraction": 0.25
},
"output": {
"primaryPlanExtractionFraction": 0.5555555555555556,
"totalPlanExtractionFraction": 0.6666666666666667
}
}Limitations and assumptions
This is plan-area recovery at uniform thickness, without ground stability, barriers, irregular boundaries or extraction sequencing.
Numerical inputs must be finite. The tool checks its declared input shape and calculation constraints; those checks do not verify the quality, calibration or representativeness of the supplied observations.
Alternative or Complementary methods
Tributary Pillar Strength: Compare calibrated square-pillar empirical strength with tributary-area stress; coefficient assumes meter dimensions and stability certification is excluded. Mining Recovery Percentage: Reconcile matched ore inventory, recovered ore and separate diluent; excludes processing recovery and requires comparable dry-tonnage definitions.
Methodological background: Pillar and Roof Span Design Guidelines for Underground Stone Mines.1
References
-
Pillar and Roof Span Design Guidelines for Underground Stone Mines — NIOSH, Centers for Disease Control and Prevention
Similar or alternative tools
- Tributary Pillar Strength
Compare calibrated square-pillar empirical strength with tributary-area stress; coefficient assumes meter dimensions and stability certification is excluded.
- Mining Recovery Percentage
Reconcile matched ore inventory, recovered ore and separate diluent; excludes processing recovery and requires comparable dry-tonnage definitions.