Industrial Minerals & Powder Processing worked example

Screening Loss at 8.64% maximum acceptable loss target: a worked example

This worked example runs the screening loss numbers for a tougher week than the baseline: 8.64% maximum acceptable loss target instead of the typical 12%. Calculate the percentage of mineral feed lost as oversize rejects or undersize fines during vibrating screen, trommel, or air classifier operations.

The inputs for this scenario

  • Rejected material (oversize + fines): 9 tons (held at the documented default)
  • Total feed to screen or classifier: 85 tons (held at the documented default)
  • Maximum acceptable loss target: 8.64 % (the input this scenario stresses; the baseline uses 12)

Working through the calculation

  • The calculation starts from the formula this tool documents: Screening loss rate = rejected material / total feed to screen x 100.
  • Screening loss rate works out to 10.59 % at these inputs, and this is the headline figure for the scenario.
  • Gap to loss target works out to -1.95 pp at these inputs.
  • Rejected material works out to 9 tons at these inputs.
  • Total feed tonnage works out to 85 tons at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where maximum acceptable loss target sits at 12% and the headline result is 10.59 %, this scenario lands almost exactly on the baseline at 10.59 %.
  • Use it after a screening or classifying run to judge separation efficiency and decide whether the deck needs cleaning or retensioning. A result at this level usually justifies acting on the stressed input before touching anything else, because every other figure in the table is downstream of it.

Results at a glance

  • Screening loss rate: 10.59 % (headline result)
  • Gap to loss target: -1.95 pp
  • Rejected material: 9 tons
  • Total feed tonnage: 85 tons

Run it with your numbers

  • To rerun this with your own numbers, open the live Screening Loss calculator, set maximum acceptable loss target to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.