TL;DR
Coarsening product and a widening closed side setting mean the liners are worn out. Measure the CSS and compare against the minimum allowed setting before scheduling a liner change.
What you might see
- product size gradually coarsening
- crusher draw increasing for same feed
- close side setting drifting open
- visible throughput decrease
Likely causes
Normal abrasive wear from hard ore, reducing liner thickness over service life
Running with a closed side setting tighter than the minimum, accelerating wear
Uneven feed distribution causing one side of the liner to wear faster
Feed containing uncrushable tramp metal damaging liner surfaces
Required tools
- CSS measurement lead slugs or rubber gauge
- Crane or lifting equipment rated for liner weight
- LOTO kit
- Measuring tape
Safety first
- Never enter the crushing chamber or reach into the feed opening without full lockout of the drive and all feed conveyors.
- Liner components on a large crusher weigh multiple tonnes. Use only rated lifting equipment and follow lifting plan.
- Falling material hazard from ore lodged in the crushing zone. Clear the chamber before any entry.
Procedure
- 1
Shut down the crusher and lock out the feed conveyor and drive.
Warning: Never reach into the crushing chamber while the main shaft or bowl may move. Engage all lockouts. - 2
Measure the closed side setting (CSS) using a lead slug or rubber CSS measurement device lowered into the crushing zone at the tightest point.[1]
- 3
Compare the measured CSS against the minimum allowable CSS for the current liner profile. Minimum values are published in the crusher documentation.[1]
- 4
If CSS is at or below the minimum, the liners are at end of life and must be replaced.
- 5
Inspect the liner surface visually through the feed opening for cracks, flat spots, or through-holes.
- 6
Check the liner backing compound between the liner and head or bowl. Loose or absent backing leads to uneven contact and liner cracking.
- 7
Plan the liner change using the documented procedure. Liner weight on a large cone or gyratory can exceed several tons, requiring a crane.
Sources
Metso Outotec Metso Nordberg C / HP / GP / Symons Crusher (Jaw / Cone / Gyratory) general technical documentation, Metso Outotec
Metso Outotec crusher operation and maintenance documentation, liner wear monitoring and CSS measurement procedures (general)
More guides for Metso Outotec Metso Nordberg C / HP / GP / Symons
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A drive overload trip means the crusher was fed beyond its capacity or a tramp event occurred. Clear the chamber, check for uncrushables, and reduce feed rate before restarting.
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A lube alarm means the crusher protection has tripped for a reason. Do not override. Check oil level, filter condition, and pump pressure before restarting.
Stop fixing the same fault twice.
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