Grinding Media Sizing

Ball mill grinding efficiency is directly influenced by the size distribution of the grinding balls in the mill. Determining the ball size (or sizes) that should be added to a plant ball mill to obtain optimal performance requires consideration of a number of factors including: circuit feed size distribution, target grind size, and ore breakage characteristics. Leveraging extensive experience, a large database of plant and pilot data, and specialized laboratory equipment and techniques, Metcom Technologies has developed a unique method for designing ball charges to best suit the characteristics of a given ore and circuit performance requirements. When applied, the economic benefits have often proven to be substantial with no capital cost!

The media size evaluation process makes use of a comprehensive database consisting of numerous tests and plant data. This is used in conjunction with your plant information to create a customized grinding media test program.

The evaluation process is typically divided into two phases.

1) Scoping Study and Customized Test Planning ($9,995)

In this initial scoping study, Metcom experts work with you to collect needed plant and process information, evaluate sample collection techniques and data quality, and interpret existing grinding circuit data, where possible, to form an initial opinion on the suitability of the grinding media size in use and the potential for improvement. Additionally, with a sample of mill feed that you provide, Metcom will run an initial, Level 1 instrumented torque mill test, at their specialized test facility, to further evaluate the potential for improvement through better media sizing.

Level 1 Scoping Study Deliverables:

  • Interpretation of the Level 1 initial torque mill test conducted on your ore.
  • Comparative database review.
  • Evaluation of existing plant data and sample quality.
  • Interpretation of existing plant information with respect to media size suitability.
  • Initial opinion on potential for performance improvement via media size changes.
  • Recommendations for next steps, which, depending on the scoping study findings, could include:
    • An immediate recommendation for media size change, if indicated.
    • Sample point and collection modifications.
    • Further plant data / sample collection (mill survey).
    • A full, Level 2 pilot test program using the Metcom torque mill

2) Pilot Scale Level 2 Torque Mill Test Program

The scoping study and initial Level 1 lab test may show the need for a Level 2 pilot test program. This phase consists of conducting tests using different media size charges in our pilot-scale instrumented torque mill. The custom test program uses samples collected from your operation and evaluates the performance of a variety of potential media size charges. The results of these tests are then interpreted and a detailed report is provided, complete with media charging practice recommendations for the plant. The cost for this test work and analysis is dependent on the number of tests required as determined in phase one.

Our media size testing facilities include a torque instrumented pilot-scale test mill, a large inventory of graded media charges for both mixed and single size charging practices, and all needed support and analysis laboratory equipment.

For questions and further details please contact us:
phone: (218) 212-4350