Main Page

SAGMILLING.COM Wiki. Theory and equations for power based modelling of mineral comminution circuits.

This work is licensed under a Commons Attribution 4.0 International License.

Grinding Circuit Modelling Documentation

This documentation describes the operating and underlying mathematics of the SAGMILLING.COM grinding circuit modelling program. It is intended to be used by the model users who want to operate and understand the functioning of grinding models.

Quick start video to get familiar with the operation of the software is available from here: https://youtu.be/J5XbCEJ6-sE

Operating the Software

• General concepts
  • Detailed concepts - Aggregating sample testwork
  • Detailed concepts - Intellectual Property
• Entering test results
  • Testwork Program
  • How to declare new Sample Names
• Creating a circuit model
  • Modelling: Transfer size limits
• Creating/modifying a mill
• How to show a sub-set of results
• How to copy data out of a table and into a spreadsheet
• How to design a new circuit using grindability testing
• How to make temporary changes to models or grindability test data and without saving
• Design choices: HPGR or SAG?
• Design choices: Pebble crushing or not?
• Design implications of Transfer Size

Specific Energy Models

• Theory of power models
• All Model types: specific energy consumption models
• SAG and ball mill circuit models
  • Raw Bond/Barratt SAB & SABC model
  • Optimized Bond/Barratt Models (including phantom cyclone allowance)
    • Optimized Bond/Barratt model SABC (pebble crushing)
    • Optimized Bond/Barratt model SAB (pebble recycle)
  • Amelunxen SAG Grindability Index (SGI) SAB and SABC model (similar to SPI™)
  • Morrell Mi (SMC) SAG & ball mill model
• Single-stage SAG milling models
  • Bond/Barratt Single stage SAG milling model
  • Morrell Mi (SMC) Single stage SAG milling model
  • El Soldado (SGI) Single stage SAG milling model
• Rod mill and ball mill circuit models
  • Bond/Rowland rod mill & ball mill model
• Multi-stage crushing and ball milling models
  • Bond/Rowland multi-stage crushing and single-stage ball mill model
  • Morrell multi-stage crushing and single-stage ball mill model
  • Bond HPGR and ball mill model (using work indices) warning, experimental!
  • Morrell HPGR and ball mill model
• Monte Carlo simulations

Mill power draw models

• Measurement of power (motor input versus shell, etc.)
• Media density for rods and balls
• Model types: mill power draw
  • Austin SAG model (hybrid phenomenological and empirical model)
  • Morrell C-model for SAG & ball mills (phenomenological model with empirical fitting). Sub-divided into:
    • a simplified model with 'typical' defaults and
    • a full model with all parameters editable.
  • Loveday/Barratt SAG model (uses an internal table of empirical "Power Numbers")
  • Nordberg ball mill model (largely empirical model)
  • Nordberg rod mill model (largely empirical model)
  • Crusher model (power allowance)

Laboratory testwork

• Comminution Testwork and test types performed in a laboratory
  • Conversions between test types
  • Ball mill work index adjustment parameters, also adjustments for Morrell Mib

Laboratory tests of grindability, impact, abrasion and compression.

• wibm: Bond ball mill work index (sometimes called "BWI")
• wirm: Bond rod mill work index (sometimes called "RWI")
• wic: Bond crushing work index (low energy impact, sometimes called "LEIT", "IWI" or "CWI")
• dwt: Drop Weight tests, SMC Test ® of SMCC Pty Ltd. and JK DWT (values stored include A×b and DWI)
• sgi: SAG Grindbility Index (also SAG Power Index™ or SPI™ of SGS Mineral Services; originally called a "Starkey SAG test"^{Starkey et al, 1994})
• ai: Bond abrasion index
• ucs: Unconfined Compressive Strength, a detailed geotechnical test conducted on drill core
• pli: Point Load Index, a field-test conducted on drill core

Geological tables, used for organizing and partitioning samples, or as proxies for test results.

• litho: Lithological, alteration and sample acquisition data, including drill hole intervals

Automatically generated tables. Assembled by the program out of the tests entered into the laboratory test tables.

• Testwork summary: Summarizes all the test results entered for a project, including samples with inadequate information for modelling.

Extra table, accessible to your administrators

• Laboratory Listing: Listing of laboratories and their colour schemes for plotting results.

• Particle size does matter
• Planning a test program for a project that does not have any testing performed yet

Monte Carlo Simulations

Simulations that use a statistical range of results rather than actual test work results. In general, the users specifies test results as a mean and a standard deviation and the model generates random work index results from a suitable Gaussian distribution. Highly recommended to operate Monte Carlo simulations in a different project from normal simulations and not to mix laboratory work index results with Monte Carlo simulation inputs.

• Monte Carlo simulations
  • Bond/Barratt Monte Carlo simulations

Administrator functions

Only people with administrator privilege are able to create new projects and designate new users. Each Client organization has at least one administrator.

• General administration concepts
• About user IDs
• Add a user
• Add a project
• Assign users to a project
• Add a laboratory to the testwork drop-down menu

Benchmarking

Examples of how the SAGMILLING.COM model compare to published information for actual milling circuits.

• Category:Benchmarking
  • Specific Energy Consumption Models
  • SAG Mill Power Draw Models, use the IMPC 2016 paper
  • Ball Mill Power Draw Models

Bibliography

• Bibliography: Specific energy consumption models
• Bibliography: Mill power draw models
• Bibliography: Testwork programs

Index

Special:Categories

Software change log

• Known Bug list