Stope Grade

Composite representative constant-area stope intervals with length and density×length weights; not ore/diluent mixing.

Description

Composite grade can be length-weighted or density-length-weighted.

Composite grade can be length-weighted or density-length-weighted. The latter represents mass weighting when sample cross-sectional areas are equal.

The tool returns densityLengthWeightedGrade (density length weighted grade); lengthWeightedGrade (length weighted grade). Input measurements and model parameters are supplied by the caller; the tool computes the stated summary rather than acquiring those measurements.

When to use Stope Grade

Use Stope Grade when you already have sampleLengthsM, sampleDensitiesTonnesPerM3, sampleGrades and want densityLengthWeightedGrade, lengthWeightedGrade. This is useful for checking a supplied calculation, documenting a measurement convention, or comparing observations prepared on the same basis.

How to use Stope Grade and understand its results

Enter sampleLengthsM, sampleDensitiesTonnesPerM3, sampleGrades 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 densityLengthWeightedGrade, lengthWeightedGrade. 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
sampleLengthsM	Sample lengths m	list of number	Required
sampleDensitiesTonnesPerM3	Sample densities tonnes per m3	list of number	Required
sampleGrades	Sample grades	list of number	Required

Use aligned nonempty positive lengths and densities with nonnegative grades. Also return the length-only weighted mean in the same grade unit.

grade = Σlength×density×grade/Σlength×density

The symbols refer to the supplied quantities or generated values described above; unit conversions and comparison boundaries follow the stated implementation.

json

{
  "input": {
    "sampleLengthsM": [
      1,
      2
    ],
    "sampleDensitiesTonnesPerM3": [
      2,
      3
    ],
    "sampleGrades": [
      1,
      4
    ]
  },
  "output": {
    "densityLengthWeightedGrade": 3.25,
    "lengthWeightedGrade": 3
  }
}

Limitations and assumptions

Equal represented cross-sectional area is assumed. Sampling support, geological domains and assay bias are not corrected.

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

Ore Tonnage: Sum block ore tonnage from bank volumes, densities and modeled ore fractions; no resource classification or geological continuity is inferred. Tailings Grade: Solve residual tailings mass and assay from a closed dry feed/concentrate balance; impossible negative or above-one assays return errors.

Methodological background: Material balance in mineral processing.^[1]

References

Material balance in mineral processing — NPTEL, Indian Institute of Technology Kanpur

Similar or alternative tools

Ore Tonnage
Sum block ore tonnage from bank volumes, densities and modeled ore fractions; no resource classification or geological continuity is inferred.
Tailings Grade
Solve residual tailings mass and assay from a closed dry feed/concentrate balance; impossible negative or above-one assays return errors.