Core Recovery Percentage

Compute run and length-weighted total core recovery from all recovered material; distinct from RQD intact-piece length filtering.

Description

Core recovery compares all recovered core length with drilled run length.

Core recovery compares all recovered core length with drilled run length. Pooling lengths weights runs by their length, rather than averaging run percentages equally.^[1]

The tool returns runCoreRecoveriesPercent, pooledCoreRecoveryPercent. The computation uses supplied observations and parameters rather than acquiring measurements.

When to use Core Recovery Percentage

Use this for the following task: Compute run and length-weighted total core recovery from all recovered material; distinct from RQD intact-piece length filtering. Prepare observations and calibration parameters on the same unit and reporting basis.

How to use Core Recovery Percentage and understand its results

Prepare the measured quantities and supplied model parameters. Match the units and align paired lists before calculating.
Enter runLengthsM, recoveredCoreLengthsM according to the field table, then run the tool.
Read runCoreRecoveriesPercent, pooledCoreRecoveryPercent. Use the calculation below to interpret the selected mean or the model’s signs, units and comparison flags.
Review the supplied assumptions and calibration before comparing or reporting the result.

Input field	Meaning	Value type and bounds	Requirement
runLengthsM	Run lengths m	list of number	Required
recoveredCoreLengthsM	Recovered core lengths m	list of number	Required

Provide aligned nonempty lists of positive run lengths and nonnegative recovered lengths no greater than each corresponding run.

run recovery% = 100×recovered/run; pooled% = 100×Σrecovered/Σrun

The symbols and boundary conditions refer to the supplied fields and the implementation described above.

Output field	Meaning	Value type
runCoreRecoveriesPercent	Run core recoveries percent	list of number
pooledCoreRecoveryPercent	Pooled core recovery percent	number

json

{
  "input": {
    "runLengthsM": [
      2,
      3
    ],
    "recoveredCoreLengthsM": [
      1.5,
      2.5
    ]
  },
  "output": {
    "runCoreRecoveriesPercent": [
      75,
      83.33333333333334
    ],
    "pooledCoreRecoveryPercent": 80
  }
}

Limitations and assumptions

This counts all recovered material. It does not apply rock-quality-designation intact-piece filtering or assess fracture causes and sampling quality.

Numerical inputs must be finite. Input-shape and calculation checks do not establish measurement quality or the validity of a supplied calibration.

Alternative or Complementary methods

Choose Joint Volume Jv when you need its operation: Calculate Jv as reciprocal normal spacings plus random-joint frequency; conventional Jv units are m⁻¹ despite its name, with no assumed RQD conversion. Choose Drill Bit Life for the complementary operation: Summarize completed bit lives, pooled cost/meter and caller linear-wear scenario; censored bits and nonlinear wear are excluded.

Background reference: Pillar and Roof Span Design Guidelines for Underground Stone Mines.

References

Pillar and Roof Span Design Guidelines for Underground Stone Mines — NIOSH, Centers for Disease Control and Prevention

Similar or alternative tools

Joint Volume Jv
Calculate Jv as reciprocal normal spacings plus random-joint frequency; conventional Jv units are m⁻¹ despite its name, with no assumed RQD conversion.
Drill Bit Life
Summarize completed bit lives, pooled cost/meter and caller linear-wear scenario; censored bits and nonlinear wear are excluded.