Bond Ball Mill Work Index

Apply a supplied Bond ball-mill laboratory correlation to closing screen and grams/revolution; constant must match test protocol and tonne convention.

Description

A Bond ball-mill laboratory correlation uses grindability in grams per revolution and a closing screen size.

A Bond ball-mill laboratory correlation uses grindability in grams per revolution and a closing screen size. Its empirical coefficient and exponents depend on the chosen test and units.^[1]

The tool returns ballMillWorkIndexKwhPerTonne. The computation uses supplied observations and parameters rather than acquiring measurements.

When to use Bond Ball Mill Work Index

Use this for the following task: Apply a supplied Bond ball-mill laboratory correlation to closing screen and grams/revolution; constant must match test protocol and tonne convention. Prepare observations and calibration parameters on the same unit and reporting basis.

How to use Bond Ball Mill Work Index and understand its results

Prepare the measured quantities and supplied model parameters. Match the units and align paired lists before calculating.
Enter closingScreenMicrometers, gramsPerRevolution, feedP80Micrometers, productP80Micrometers, empiricalConstant, screenExponent, grindabilityExponent according to the field table, then run the tool.
Read ballMillWorkIndexKwhPerTonne. 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
closingScreenMicrometers	Closing screen micrometers	number	Required
gramsPerRevolution	Grams per revolution	number	Required
feedP80Micrometers	Feed p80 micrometers	number	Required
productP80Micrometers	Product p80 micrometers	number	Required
empiricalConstant	Empirical constant	number	Required
screenExponent	Screen exponent	number	Required
grindabilityExponent	Grindability exponent	number	Required

Supply positive screen size, grindability, empirical constant and exponents. Feed and product P80 sizes are positive micrometres with product smaller than feed.

work index = empiricalConstant/(screenSize^screenExponent×gramsPerRevolution^grindabilityExponent×(10/√productP80−10/√feedP80))

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

Output field	Meaning	Value type
ballMillWorkIndexKwhPerTonne	Ball mill work index kwh per tonne	number

json

{
  "input": {
    "closingScreenMicrometers": 100,
    "gramsPerRevolution": 2,
    "feedP80Micrometers": 10000,
    "productP80Micrometers": 100,
    "empiricalConstant": 44.5,
    "screenExponent": 0.23,
    "grindabilityExponent": 0.82
  },
  "output": {
    "ballMillWorkIndexKwhPerTonne": 9.711200149476227
  }
}

Limitations and assumptions

The caller must supply compatible test results and coefficient conventions. The tool does not run the laboratory procedure, select corrections or validate sample representativeness.

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 Bond Work Index when you need its operation: Infer Bond work index from measured net specific energy and feed/product P80; distinct from the laboratory ball-mill test correlation. Choose Comminution Energy for the complementary operation: Predict corrected Bond net energy and power for supplied throughput; no-load mill power and hardware sizing are excluded.

Background reference: Determining the Bond Efficiency of Industrial Grinding Circuits.

References

Determining the Bond Efficiency of Industrial Grinding Circuits — Global Mining Guidelines Group

Similar or alternative tools

Bond Work Index
Infer Bond work index from measured net specific energy and feed/product P80; distinct from the laboratory ball-mill test correlation.
Comminution Energy
Predict corrected Bond net energy and power for supplied throughput; no-load mill power and hardware sizing are excluded.