Chute Liner Thickness Selection Table
There is no universal chute liner thickness table that can safely convert only tonnage or lump size into a finished plate thickness. Thickness is a system decision involving wear rate, impact, panel span, fixing, shell condition, minimum opening, mass, access and the replacement interval.
The table in this guide is a decision framework, not a prescriptive engineering chart. Use it to collect evidence and compare alternatives before the responsible engineer approves the drawing.
Confirm the current shell, supports and downstream clearances before approving any thickness change.
Thickness-selection decision table
| Input | Evidence to collect | How it affects the review |
|---|---|---|
| Wear mechanism | Sliding band, impact crater, edge lift, build-up or corrosion pattern. | Determines whether added wear allowance addresses the controlling failure. |
| Wear rate | Original and remaining thickness by location, plus hours or tonnage. | Supports an evidence-based replacement interval. |
| Impact | Lump size, drop, velocity, angle and rebound area. | May shift the decision toward toughness, support or flow control instead of thickness alone. |
| Panel support | Shell condition, unsupported span, backing and fixing layout. | A poorly supported thick panel can still crack, move or damage the shell. |
| Flow envelope | Minimum opening, joints, receiving equipment and build-up margin. | Additional thickness can narrow or redirect the material path. |
| Maintenance | Individual mass, access opening, lifting device and shutdown sequence. | Limits practical panel size and wear allowance. |
Map thickness by wear zone
Start with a numbered liner map and a repeatable measurement grid. Record original thickness, remaining thickness, date, operating hours or throughput, and the measurement method. One minimum reading does not describe whether wear is stable, moving or concentrated around a joint.
Divide the chute into primary impact, sliding path, rebound sidewall, transition and lower-wear access zones. Different thicknesses or materials may be justified, but steps between panels must be drawn relative to flow direction.
Use measured wear rate carefully
A simple planning rate can be calculated as thickness loss divided by the associated operating period or tonnage. Treat it as a historical observation, not a permanent material constant. Changes in ore source, moisture, crusher setting, throughput, belt tracking or build-up can move the stream and invalidate a straight-line forecast.
| Observation | Do not assume | Follow-up |
|---|---|---|
| Uniform loss over several surveys | Every zone wears at the same rate. | Maintain the measurement grid and compare locations. |
| One sudden low reading | The whole panel is near end of life. | Confirm surface preparation, instrument access and nearby readings. |
| Faster wear after a process change | The plate chemistry changed. | Review throughput, trajectory, lump size and operating condition. |
| Thickness remains but plate cracks | More thickness will prevent recurrence. | Investigate impact, support, constraint, fit and toughness. |
Preserve the minimum clear opening
Increasing thickness on both walls and the floor can materially reduce a chute throat. Check the as-built shell, liner stack-up, fastener heads, overlaps, expected build-up and downstream opening. The drawing should state the minimum clear section after installation, not only the nominal shell dimensions.
NIOSH’s transfer-point guidance emphasizes flow without clogging or jamming and avoiding abrupt changes in direction. It does not prescribe liner thickness, but it shows why thickness cannot be separated from the flow envelope.
Impact zone: thickness is not the only variable
A concentrated impact crater can indicate that the stream strikes a small, unsupported area. Review impact angle, support span, panel size, fixing protection and whether an approved impact plate or rock box should control the first contact. Simply adding a thicker, harder plate may increase mass without correcting the load path.
Sliding zone: plan wear allowance and joints together
Where stable sliding abrasion dominates, additional wear allowance may extend the measurement interval. However, an upstream-facing ledge at a thick-to-thin transition can create turbulence, edge impact and packing. Show overlaps, gaps and thickness changes with the flow arrow. See the panel-joint and flow-direction checklist.
Material grade changes the thickness discussion
Harder abrasion-resistant steel, a tougher lower-hardness plate, a cast alloy and a ceramic-rubber liner do not behave as identical thicknesses. Material choice changes wear allowance, impact response, forming, attachment and failure mode. Do not use a thickness table to declare different materials equivalent.
For NM-class plate, the current Chinese standard reference is GB/T 24186-2022. The material grades selection guide organizes the wider comparison.
Panel span, fixing and shell condition
Record the unsupported span, shell thickness, stiffener position, hole condition and backing. A liner is a replaceable wear component, not an automatic substitute for a damaged structural shell. The responsible engineer must approve support and fixing loads. If holes are elongated or bolts repeatedly loosen, investigate movement before increasing thickness.
Panel mass and access
Mass grows with area, thickness, density and attachments. State the calculated finished mass on the drawing and compare it with the approved lifting method and access opening. A single thick plate may have fewer joints but be impossible to handle safely. Modular panels can reduce mass and allow selective replacement, but they add joints and part numbers.
Define a replacement limit
The limit may consider minimum remaining section, fixing security, hole or recess integrity, crack evidence, shell exposure and the time required to reach the next planned shutdown. It should be a site-approved criterion, not a universal percentage copied from another chute. Record the inspection method and repeatable measurement locations.
Worked decision example without a universal answer
| Evidence | Option A | Option B | Decision question |
|---|---|---|---|
| Stable sliding wear; opening has margin | Increase wear allowance in the measured band. | Use a more abrasion-resistant compatible material at current thickness. | Which option meets life, processing and installation requirements with less system risk? |
| Local impact cracking; plate remains thick | Increase thickness. | Improve support, panelization, toughness or flow-control arrangement. | Is thickness loss or mechanical damage controlling replacement? |
| Heavy panel exceeds lifting limit | Retain one-piece geometry. | Split into approved modular panels. | Can joints be added without creating a flow-facing ledge? |
| Throat already marginal | Add thickness inward. | Review external shell change, material choice or wear-zone-only increase. | How will minimum clear opening be preserved? |
Inspection evidence before shipment
Verify plate thickness and finished geometry against the drawing, not against a marketing class. Confirm profile, bend, countersink depth, fastener length, individual mass and part marking. Where hardness is specified, record method, scale, location and acceptance range. Use the pre-shipment inspection checklist.
RFQ checklist
- liner map with flow direction and original thicknesses;
- repeatable remaining-thickness grid with dates and service exposure;
- material type, lump size, moisture, throughput and drop geometry;
- wear/failure photographs before and after cleaning;
- shell, support, fixing and opening dimensions;
- access opening, lifting limit and shutdown interval;
- approved material specification and any zone-specific alternatives;
- replacement limit, inspection evidence and part-marking requirements.
Related resources: wear mapping and replacement planning, maintenance access planning and modular chute liner panels.
Technical review and safety boundary
This framework does not calculate structural capacity or prescribe a safe thickness. Inspection and replacement must follow the site’s isolation, stored-energy, lifting and confined-space controls. Updated by the EB China engineering-content team against the cited standard and NIOSH source. The owner’s approved drawing and engineering review govern the final material, thickness and installation.