Industrial Minerals & Powder Processing calculator
Screening Loss Calculator
Calculate the percentage of mineral feed lost as oversize rejects or undersize fines during vibrating screen, trommel, or air classifier operations. Use it to track reject rates, compare screen media options, and decide when screen replacement or classifier adjustment is justified.
What this calculator does
- Calculate the percentage of mineral feed lost as oversize rejects or undersize fines during vibrating screen, trommel, or air classifier operations.
- Use it when a process engineer or quality manager needs to quantify screening losses, track reject rates over time, or justify screen media replacement, classifier tuning, or circuit redesign.
- Shows the percentage of feed material lost during screening or classification, and whether that loss exceeds your target.
Formula used
- Screening loss rate = rejected material / total feed to screen x 100
- Gap to target = screening loss rate - maximum acceptable loss target
Inputs explained
- Rejected material (oversize + fines): Enter the combined tons of oversize rejects and undersize fines removed during screening or classification. Weigh reject streams or use belt scale data.
- Total feed to screen or classifier: Enter the total tons fed to the screening or classification step during the same period.
- Maximum acceptable loss target: Enter the maximum tolerable screening loss for this product and circuit. Typical targets: 5% to 15% depending on specification tightness and feed variability.
How to use the result
- Use to monitor screen condition, compare wire cloth versus polyurethane panels, track classifier drift, or justify circuit changes.
- Results depend on feed size distribution, moisture, screen open area, vibration amplitude and frequency, deck angle, material bed depth, blinding, and classifier air volume. Validate with physical sampling and sieve analysis.
Common questions
- What information do I need before using the Screening Loss calculator? You need the tons of rejected material (oversize plus fines), total tons fed to the screen, and your maximum acceptable loss percentage.
- What does the result mean? The result shows what percentage of feed is being lost as rejects and whether that loss rate exceeds your operational target.
- When is the result only an estimate? Always. Screening efficiency varies with moisture, feed rate, particle shape, screen condition, and equipment settings. Track over time for meaningful trends.
- What decision can I make from the result? Use it to schedule screen media replacement, adjust vibration settings, change classifier speed, rework rejects through a secondary circuit, or quantify the cost of lost product.
Last reviewed 2026-05-12.